[PATCH 30/30] sched_ext: Add selftests
View on Lore: https://lore.kernel.org/all/20240618212056.2833381-31-tj@kernel.org
Commit Message
From: David Vernet <dvernet@meta.com>
Add basic selftests.
Signed-off-by: David Vernet <dvernet@meta.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
tools/testing/selftests/sched_ext/.gitignore | 6 +
tools/testing/selftests/sched_ext/Makefile | 218 ++++++++++++++++++
tools/testing/selftests/sched_ext/config | 9 +
.../selftests/sched_ext/create_dsq.bpf.c | 58 +++++
.../testing/selftests/sched_ext/create_dsq.c | 57 +++++
.../sched_ext/ddsp_bogus_dsq_fail.bpf.c | 42 ++++
.../selftests/sched_ext/ddsp_bogus_dsq_fail.c | 57 +++++
.../sched_ext/ddsp_vtimelocal_fail.bpf.c | 39 ++++
.../sched_ext/ddsp_vtimelocal_fail.c | 56 +++++
.../selftests/sched_ext/dsp_local_on.bpf.c | 65 ++++++
.../selftests/sched_ext/dsp_local_on.c | 58 +++++
.../sched_ext/enq_last_no_enq_fails.bpf.c | 21 ++
.../sched_ext/enq_last_no_enq_fails.c | 60 +++++
.../sched_ext/enq_select_cpu_fails.bpf.c | 43 ++++
.../sched_ext/enq_select_cpu_fails.c | 61 +++++
tools/testing/selftests/sched_ext/exit.bpf.c | 84 +++++++
tools/testing/selftests/sched_ext/exit.c | 55 +++++
tools/testing/selftests/sched_ext/exit_test.h | 20 ++
.../testing/selftests/sched_ext/hotplug.bpf.c | 61 +++++
tools/testing/selftests/sched_ext/hotplug.c | 168 ++++++++++++++
.../selftests/sched_ext/hotplug_test.h | 15 ++
.../sched_ext/init_enable_count.bpf.c | 53 +++++
.../selftests/sched_ext/init_enable_count.c | 166 +++++++++++++
.../testing/selftests/sched_ext/maximal.bpf.c | 132 +++++++++++
tools/testing/selftests/sched_ext/maximal.c | 51 ++++
.../selftests/sched_ext/maybe_null.bpf.c | 36 +++
.../testing/selftests/sched_ext/maybe_null.c | 49 ++++
.../sched_ext/maybe_null_fail_dsp.bpf.c | 25 ++
.../sched_ext/maybe_null_fail_yld.bpf.c | 28 +++
.../testing/selftests/sched_ext/minimal.bpf.c | 21 ++
tools/testing/selftests/sched_ext/minimal.c | 58 +++++
.../selftests/sched_ext/prog_run.bpf.c | 32 +++
tools/testing/selftests/sched_ext/prog_run.c | 78 +++++++
.../testing/selftests/sched_ext/reload_loop.c | 75 ++++++
tools/testing/selftests/sched_ext/runner.c | 201 ++++++++++++++++
tools/testing/selftests/sched_ext/scx_test.h | 131 +++++++++++
.../selftests/sched_ext/select_cpu_dfl.bpf.c | 40 ++++
.../selftests/sched_ext/select_cpu_dfl.c | 72 ++++++
.../sched_ext/select_cpu_dfl_nodispatch.bpf.c | 89 +++++++
.../sched_ext/select_cpu_dfl_nodispatch.c | 72 ++++++
.../sched_ext/select_cpu_dispatch.bpf.c | 41 ++++
.../selftests/sched_ext/select_cpu_dispatch.c | 70 ++++++
.../select_cpu_dispatch_bad_dsq.bpf.c | 37 +++
.../sched_ext/select_cpu_dispatch_bad_dsq.c | 56 +++++
.../select_cpu_dispatch_dbl_dsp.bpf.c | 38 +++
.../sched_ext/select_cpu_dispatch_dbl_dsp.c | 56 +++++
.../sched_ext/select_cpu_vtime.bpf.c | 92 ++++++++
.../selftests/sched_ext/select_cpu_vtime.c | 59 +++++
.../selftests/sched_ext/test_example.c | 49 ++++
tools/testing/selftests/sched_ext/util.c | 71 ++++++
tools/testing/selftests/sched_ext/util.h | 13 ++
51 files changed, 3244 insertions(+)
create mode 100644 tools/testing/selftests/sched_ext/.gitignore
create mode 100644 tools/testing/selftests/sched_ext/Makefile
create mode 100644 tools/testing/selftests/sched_ext/config
create mode 100644 tools/testing/selftests/sched_ext/create_dsq.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/create_dsq.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
create mode 100644 tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/dsp_local_on.c
create mode 100644 tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
create mode 100644 tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
create mode 100644 tools/testing/selftests/sched_ext/exit.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/exit.c
create mode 100644 tools/testing/selftests/sched_ext/exit_test.h
create mode 100644 tools/testing/selftests/sched_ext/hotplug.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/hotplug.c
create mode 100644 tools/testing/selftests/sched_ext/hotplug_test.h
create mode 100644 tools/testing/selftests/sched_ext/init_enable_count.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/init_enable_count.c
create mode 100644 tools/testing/selftests/sched_ext/maximal.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maximal.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/minimal.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/minimal.c
create mode 100644 tools/testing/selftests/sched_ext/prog_run.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/prog_run.c
create mode 100644 tools/testing/selftests/sched_ext/reload_loop.c
create mode 100644 tools/testing/selftests/sched_ext/runner.c
create mode 100644 tools/testing/selftests/sched_ext/scx_test.h
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_vtime.c
create mode 100644 tools/testing/selftests/sched_ext/test_example.c
create mode 100644 tools/testing/selftests/sched_ext/util.c
create mode 100644 tools/testing/selftests/sched_ext/util.h
diff --git a/tools/testing/selftests/sched_ext/.gitignore b/tools/testing/selftests/sched_ext/.gitignore
new file mode 100644
index 000000000000..ae5491a114c0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/.gitignore
@@ -0,0 +1,6 @@
+*
+!*.c
+!*.h
+!Makefile
+!.gitignore
+!config
diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile
new file mode 100644
index 000000000000..0754a2c110a1
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/Makefile
@@ -0,0 +1,218 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
+include ../../../build/Build.include
+include ../../../scripts/Makefile.arch
+include ../../../scripts/Makefile.include
+include ../lib.mk
+
+ifneq ($(LLVM),)
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+CC := $(LLVM_PREFIX)clang$(LLVM_SUFFIX) $(CLANG_FLAGS) -fintegrated-as
+else
+CC := gcc
+endif # LLVM
+
+ifneq ($(CROSS_COMPILE),)
+$(error CROSS_COMPILE not supported for scx selftests)
+endif # CROSS_COMPILE
+
+CURDIR := $(abspath .)
+REPOROOT := $(abspath ../../../..)
+TOOLSDIR := $(REPOROOT)/tools
+LIBDIR := $(TOOLSDIR)/lib
+BPFDIR := $(LIBDIR)/bpf
+TOOLSINCDIR := $(TOOLSDIR)/include
+BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool
+APIDIR := $(TOOLSINCDIR)/uapi
+GENDIR := $(REPOROOT)/include/generated
+GENHDR := $(GENDIR)/autoconf.h
+SCXTOOLSDIR := $(TOOLSDIR)/sched_ext
+SCXTOOLSINCDIR := $(TOOLSDIR)/sched_ext/include
+
+OUTPUT_DIR := $(CURDIR)/build
+OBJ_DIR := $(OUTPUT_DIR)/obj
+INCLUDE_DIR := $(OUTPUT_DIR)/include
+BPFOBJ_DIR := $(OBJ_DIR)/libbpf
+SCXOBJ_DIR := $(OBJ_DIR)/sched_ext
+BPFOBJ := $(BPFOBJ_DIR)/libbpf.a
+LIBBPF_OUTPUT := $(OBJ_DIR)/libbpf/libbpf.a
+DEFAULT_BPFTOOL := $(OUTPUT_DIR)/sbin/bpftool
+HOST_BUILD_DIR := $(OBJ_DIR)
+HOST_OUTPUT_DIR := $(OUTPUT_DIR)
+
+VMLINUX_BTF_PATHS ?= ../../../../vmlinux \
+ /sys/kernel/btf/vmlinux \
+ /boot/vmlinux-$(shell uname -r)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+ifeq ($(VMLINUX_BTF),)
+$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
+endif
+
+BPFTOOL ?= $(DEFAULT_BPFTOOL)
+
+ifneq ($(wildcard $(GENHDR)),)
+ GENFLAGS := -DHAVE_GENHDR
+endif
+
+CFLAGS += -g -O2 -rdynamic -pthread -Wall -Werror $(GENFLAGS) \
+ -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \
+ -I$(TOOLSINCDIR) -I$(APIDIR) -I$(CURDIR)/include -I$(SCXTOOLSINCDIR)
+
+# Silence some warnings when compiled with clang
+ifneq ($(LLVM),)
+CFLAGS += -Wno-unused-command-line-argument
+endif
+
+LDFLAGS = -lelf -lz -lpthread -lzstd
+
+IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
+ grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
+
+# Get Clang's default includes on this system, as opposed to those seen by
+# '-target bpf'. This fixes "missing" files on some architectures/distros,
+# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
+#
+# Use '-idirafter': Don't interfere with include mechanics except where the
+# build would have failed anyways.
+define get_sys_includes
+$(shell $(1) -v -E - </dev/null 2>&1 \
+ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
+$(shell $(1) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}')
+endef
+
+BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) \
+ $(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian) \
+ -I$(CURDIR)/include -I$(CURDIR)/include/bpf-compat \
+ -I$(INCLUDE_DIR) -I$(APIDIR) -I$(SCXTOOLSINCDIR) \
+ -I$(REPOROOT)/include \
+ $(call get_sys_includes,$(CLANG)) \
+ -Wall -Wno-compare-distinct-pointer-types \
+ -Wno-incompatible-function-pointer-types \
+ -O2 -mcpu=v3
+
+# sort removes libbpf duplicates when not cross-building
+MAKE_DIRS := $(sort $(OBJ_DIR)/libbpf $(OBJ_DIR)/libbpf \
+ $(OBJ_DIR)/bpftool $(OBJ_DIR)/resolve_btfids \
+ $(INCLUDE_DIR) $(SCXOBJ_DIR))
+
+$(MAKE_DIRS):
+ $(call msg,MKDIR,,$@)
+ $(Q)mkdir -p $@
+
+$(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
+ $(APIDIR)/linux/bpf.h \
+ | $(OBJ_DIR)/libbpf
+ $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
+ EXTRA_CFLAGS='-g -O0 -fPIC' \
+ DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
+
+$(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
+ $(LIBBPF_OUTPUT) | $(OBJ_DIR)/bpftool
+ $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
+ ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
+ EXTRA_CFLAGS='-g -O0' \
+ OUTPUT=$(OBJ_DIR)/bpftool/ \
+ LIBBPF_OUTPUT=$(OBJ_DIR)/libbpf/ \
+ LIBBPF_DESTDIR=$(OUTPUT_DIR)/ \
+ prefix= DESTDIR=$(OUTPUT_DIR)/ install-bin
+
+$(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
+ifeq ($(VMLINUX_H),)
+ $(call msg,GEN,,$@)
+ $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+else
+ $(call msg,CP,,$@)
+ $(Q)cp "$(VMLINUX_H)" $@
+endif
+
+$(SCXOBJ_DIR)/%.bpf.o: %.bpf.c $(INCLUDE_DIR)/vmlinux.h | $(BPFOBJ) $(SCXOBJ_DIR)
+ $(call msg,CLNG-BPF,,$(notdir $@))
+ $(Q)$(CLANG) $(BPF_CFLAGS) -target bpf -c $< -o $@
+
+$(INCLUDE_DIR)/%.bpf.skel.h: $(SCXOBJ_DIR)/%.bpf.o $(INCLUDE_DIR)/vmlinux.h $(BPFTOOL) | $(INCLUDE_DIR)
+ $(eval sched=$(notdir $@))
+ $(call msg,GEN-SKEL,,$(sched))
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked1.o) $<
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked2.o) $(<:.o=.linked1.o)
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked3.o) $(<:.o=.linked2.o)
+ $(Q)diff $(<:.o=.linked2.o) $(<:.o=.linked3.o)
+ $(Q)$(BPFTOOL) gen skeleton $(<:.o=.linked3.o) name $(subst .bpf.skel.h,,$(sched)) > $@
+ $(Q)$(BPFTOOL) gen subskeleton $(<:.o=.linked3.o) name $(subst .bpf.skel.h,,$(sched)) > $(@:.skel.h=.subskel.h)
+
+################
+# C schedulers #
+################
+
+override define CLEAN
+ rm -rf $(OUTPUT_DIR)
+ rm -f *.o *.bpf.o *.bpf.skel.h *.bpf.subskel.h
+ rm -f $(TEST_GEN_PROGS)
+ rm -f runner
+endef
+
+# Every testcase takes all of the BPF progs are dependencies by default. This
+# allows testcases to load any BPF scheduler, which is useful for testcases
+# that don't need their own prog to run their test.
+all_test_bpfprogs := $(foreach prog,$(wildcard *.bpf.c),$(INCLUDE_DIR)/$(patsubst %.c,%.skel.h,$(prog)))
+
+auto-test-targets := \
+ create_dsq \
+ enq_last_no_enq_fails \
+ enq_select_cpu_fails \
+ ddsp_bogus_dsq_fail \
+ ddsp_vtimelocal_fail \
+ dsp_local_on \
+ exit \
+ hotplug \
+ init_enable_count \
+ maximal \
+ maybe_null \
+ minimal \
+ prog_run \
+ reload_loop \
+ select_cpu_dfl \
+ select_cpu_dfl_nodispatch \
+ select_cpu_dispatch \
+ select_cpu_dispatch_bad_dsq \
+ select_cpu_dispatch_dbl_dsp \
+ select_cpu_vtime \
+ test_example \
+
+testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets)))
+
+$(SCXOBJ_DIR)/runner.o: runner.c | $(SCXOBJ_DIR)
+ $(CC) $(CFLAGS) -c $< -o $@
+
+# Create all of the test targets object files, whose testcase objects will be
+# registered into the runner in ELF constructors.
+#
+# Note that we must do double expansion here in order to support conditionally
+# compiling BPF object files only if one is present, as the wildcard Make
+# function doesn't support using implicit rules otherwise.
+$(testcase-targets): $(SCXOBJ_DIR)/%.o: %.c $(SCXOBJ_DIR)/runner.o $(all_test_bpfprogs) | $(SCXOBJ_DIR)
+ $(eval test=$(patsubst %.o,%.c,$(notdir $@)))
+ $(CC) $(CFLAGS) -c $< -o $@ $(SCXOBJ_DIR)/runner.o
+
+$(SCXOBJ_DIR)/util.o: util.c | $(SCXOBJ_DIR)
+ $(CC) $(CFLAGS) -c $< -o $@
+
+runner: $(SCXOBJ_DIR)/runner.o $(SCXOBJ_DIR)/util.o $(BPFOBJ) $(testcase-targets)
+ @echo "$(testcase-targets)"
+ $(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+TEST_GEN_PROGS := runner
+
+all: runner
+
+.PHONY: all clean help
+
+.DEFAULT_GOAL := all
+
+.DELETE_ON_ERROR:
+
+.SECONDARY:
diff --git a/tools/testing/selftests/sched_ext/config b/tools/testing/selftests/sched_ext/config
new file mode 100644
index 000000000000..0de9b4ee249d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/config
@@ -0,0 +1,9 @@
+CONFIG_SCHED_DEBUG=y
+CONFIG_SCHED_CLASS_EXT=y
+CONFIG_CGROUPS=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_EXT_GROUP_SCHED=y
+CONFIG_BPF=y
+CONFIG_BPF_SYSCALL=y
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_INFO_BTF=y
diff --git a/tools/testing/selftests/sched_ext/create_dsq.bpf.c b/tools/testing/selftests/sched_ext/create_dsq.bpf.c
new file mode 100644
index 000000000000..23f79ed343f0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/create_dsq.bpf.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Create and destroy DSQs in a loop.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+void BPF_STRUCT_OPS(create_dsq_exit_task, struct task_struct *p,
+ struct scx_exit_task_args *args)
+{
+ scx_bpf_destroy_dsq(p->pid);
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(create_dsq_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ s32 err;
+
+ err = scx_bpf_create_dsq(p->pid, -1);
+ if (err)
+ scx_bpf_error("Failed to create DSQ for %s[%d]",
+ p->comm, p->pid);
+
+ return err;
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(create_dsq_init)
+{
+ u32 i;
+ s32 err;
+
+ bpf_for(i, 0, 1024) {
+ err = scx_bpf_create_dsq(i, -1);
+ if (err) {
+ scx_bpf_error("Failed to create DSQ %d", i);
+ return 0;
+ }
+ }
+
+ bpf_for(i, 0, 1024) {
+ scx_bpf_destroy_dsq(i);
+ }
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops create_dsq_ops = {
+ .init_task = create_dsq_init_task,
+ .exit_task = create_dsq_exit_task,
+ .init = create_dsq_init,
+ .name = "create_dsq",
+};
diff --git a/tools/testing/selftests/sched_ext/create_dsq.c b/tools/testing/selftests/sched_ext/create_dsq.c
new file mode 100644
index 000000000000..fa946d9146d4
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/create_dsq.c
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "create_dsq.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct create_dsq *skel;
+
+ skel = create_dsq__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct create_dsq *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.create_dsq_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct create_dsq *skel = ctx;
+
+ create_dsq__destroy(skel);
+}
+
+struct scx_test create_dsq = {
+ .name = "create_dsq",
+ .description = "Create and destroy a dsq in a loop",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&create_dsq)
diff --git a/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
new file mode 100644
index 000000000000..e97ad41d354a
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+
+ if (cpu >= 0) {
+ /*
+ * If we dispatch to a bogus DSQ that will fall back to the
+ * builtin global DSQ, we fail gracefully.
+ */
+ scx_bpf_dispatch_vtime(p, 0xcafef00d, SCX_SLICE_DFL,
+ p->scx.dsq_vtime, 0);
+ return cpu;
+ }
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops ddsp_bogus_dsq_fail_ops = {
+ .select_cpu = ddsp_bogus_dsq_fail_select_cpu,
+ .exit = ddsp_bogus_dsq_fail_exit,
+ .name = "ddsp_bogus_dsq_fail",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
new file mode 100644
index 000000000000..e65d22f23f3b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "ddsp_bogus_dsq_fail.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel;
+
+ skel = ddsp_bogus_dsq_fail__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.ddsp_bogus_dsq_fail_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel = ctx;
+
+ ddsp_bogus_dsq_fail__destroy(skel);
+}
+
+struct scx_test ddsp_bogus_dsq_fail = {
+ .name = "ddsp_bogus_dsq_fail",
+ .description = "Verify we gracefully fail, and fall back to using a "
+ "built-in DSQ, if we do a direct dispatch to an invalid"
+ " DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&ddsp_bogus_dsq_fail)
diff --git a/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
new file mode 100644
index 000000000000..dde7e7dafbfb
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(ddsp_vtimelocal_fail_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+
+ if (cpu >= 0) {
+ /* Shouldn't be allowed to vtime dispatch to a builtin DSQ. */
+ scx_bpf_dispatch_vtime(p, SCX_DSQ_LOCAL, SCX_SLICE_DFL,
+ p->scx.dsq_vtime, 0);
+ return cpu;
+ }
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(ddsp_vtimelocal_fail_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops ddsp_vtimelocal_fail_ops = {
+ .select_cpu = ddsp_vtimelocal_fail_select_cpu,
+ .exit = ddsp_vtimelocal_fail_exit,
+ .name = "ddsp_vtimelocal_fail",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
new file mode 100644
index 000000000000..abafee587cd6
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <unistd.h>
+#include "ddsp_vtimelocal_fail.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct ddsp_vtimelocal_fail *skel;
+
+ skel = ddsp_vtimelocal_fail__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct ddsp_vtimelocal_fail *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.ddsp_vtimelocal_fail_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct ddsp_vtimelocal_fail *skel = ctx;
+
+ ddsp_vtimelocal_fail__destroy(skel);
+}
+
+struct scx_test ddsp_vtimelocal_fail = {
+ .name = "ddsp_vtimelocal_fail",
+ .description = "Verify we gracefully fail, and fall back to using a "
+ "built-in DSQ, if we do a direct vtime dispatch to a "
+ "built-in DSQ from DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&ddsp_vtimelocal_fail)
diff --git a/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c b/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
new file mode 100644
index 000000000000..efb4672decb4
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+const volatile s32 nr_cpus;
+
+UEI_DEFINE(uei);
+
+struct {
+ __uint(type, BPF_MAP_TYPE_QUEUE);
+ __uint(max_entries, 8192);
+ __type(value, s32);
+} queue SEC(".maps");
+
+s32 BPF_STRUCT_OPS(dsp_local_on_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ s32 pid = p->pid;
+
+ if (bpf_map_push_elem(&queue, &pid, 0))
+ scx_bpf_error("Failed to enqueue %s[%d]", p->comm, p->pid);
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_dispatch, s32 cpu, struct task_struct *prev)
+{
+ s32 pid, target;
+ struct task_struct *p;
+
+ if (bpf_map_pop_elem(&queue, &pid))
+ return;
+
+ p = bpf_task_from_pid(pid);
+ if (!p)
+ return;
+
+ target = bpf_get_prandom_u32() % nr_cpus;
+
+ scx_bpf_dispatch(p, SCX_DSQ_LOCAL_ON | target, SCX_SLICE_DFL, 0);
+ bpf_task_release(p);
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops dsp_local_on_ops = {
+ .select_cpu = dsp_local_on_select_cpu,
+ .enqueue = dsp_local_on_enqueue,
+ .dispatch = dsp_local_on_dispatch,
+ .exit = dsp_local_on_exit,
+ .name = "dsp_local_on",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/dsp_local_on.c b/tools/testing/selftests/sched_ext/dsp_local_on.c
new file mode 100644
index 000000000000..472851b56854
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/dsp_local_on.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <unistd.h>
+#include "dsp_local_on.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct dsp_local_on *skel;
+
+ skel = dsp_local_on__open();
+ SCX_FAIL_IF(!skel, "Failed to open");
+
+ skel->rodata->nr_cpus = libbpf_num_possible_cpus();
+ SCX_FAIL_IF(dsp_local_on__load(skel), "Failed to load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct dsp_local_on *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.dsp_local_on_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ /* Just sleeping is fine, plenty of scheduling events happening */
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct dsp_local_on *skel = ctx;
+
+ dsp_local_on__destroy(skel);
+}
+
+struct scx_test dsp_local_on = {
+ .name = "dsp_local_on",
+ .description = "Verify we can directly dispatch tasks to a local DSQs "
+ "from osp.dispatch()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&dsp_local_on)
diff --git a/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
new file mode 100644
index 000000000000..b0b99531d5d5
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+SEC(".struct_ops.link")
+struct sched_ext_ops enq_last_no_enq_fails_ops = {
+ .name = "enq_last_no_enq_fails",
+ /* Need to define ops.enqueue() with SCX_OPS_ENQ_LAST */
+ .flags = SCX_OPS_ENQ_LAST,
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
new file mode 100644
index 000000000000..2a3eda5e2c0b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "enq_last_no_enq_fails.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct enq_last_no_enq_fails *skel;
+
+ skel = enq_last_no_enq_fails__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct enq_last_no_enq_fails *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.enq_last_no_enq_fails_ops);
+ if (link) {
+ SCX_ERR("Incorrectly succeeded in to attaching scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct enq_last_no_enq_fails *skel = ctx;
+
+ enq_last_no_enq_fails__destroy(skel);
+}
+
+struct scx_test enq_last_no_enq_fails = {
+ .name = "enq_last_no_enq_fails",
+ .description = "Verify we fail to load a scheduler if we specify "
+ "the SCX_OPS_ENQ_LAST flag without defining "
+ "ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&enq_last_no_enq_fails)
diff --git a/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
new file mode 100644
index 000000000000..b3dfc1033cd6
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+/* Manually specify the signature until the kfunc is added to the scx repo. */
+s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
+ bool *found) __ksym;
+
+s32 BPF_STRUCT_OPS(enq_select_cpu_fails_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(enq_select_cpu_fails_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ /*
+ * Need to initialize the variable or the verifier will fail to load.
+ * Improving these semantics is actively being worked on.
+ */
+ bool found = false;
+
+ /* Can only call from ops.select_cpu() */
+ scx_bpf_select_cpu_dfl(p, 0, 0, &found);
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops enq_select_cpu_fails_ops = {
+ .select_cpu = enq_select_cpu_fails_select_cpu,
+ .enqueue = enq_select_cpu_fails_enqueue,
+ .name = "enq_select_cpu_fails",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
new file mode 100644
index 000000000000..dd1350e5f002
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "enq_select_cpu_fails.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct enq_select_cpu_fails *skel;
+
+ skel = enq_select_cpu_fails__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct enq_select_cpu_fails *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.enq_select_cpu_fails_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ sleep(1);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct enq_select_cpu_fails *skel = ctx;
+
+ enq_select_cpu_fails__destroy(skel);
+}
+
+struct scx_test enq_select_cpu_fails = {
+ .name = "enq_select_cpu_fails",
+ .description = "Verify we fail to call scx_bpf_select_cpu_dfl() "
+ "from ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&enq_select_cpu_fails)
diff --git a/tools/testing/selftests/sched_ext/exit.bpf.c b/tools/testing/selftests/sched_ext/exit.bpf.c
new file mode 100644
index 000000000000..ae12ddaac921
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit.bpf.c
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+#include "exit_test.h"
+
+const volatile int exit_point;
+UEI_DEFINE(uei);
+
+#define EXIT_CLEANLY() scx_bpf_exit(exit_point, "%d", exit_point)
+
+s32 BPF_STRUCT_OPS(exit_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ bool found;
+
+ if (exit_point == EXIT_SELECT_CPU)
+ EXIT_CLEANLY();
+
+ return scx_bpf_select_cpu_dfl(p, prev_cpu, wake_flags, &found);
+}
+
+void BPF_STRUCT_OPS(exit_enqueue, struct task_struct *p, u64 enq_flags)
+{
+ if (exit_point == EXIT_ENQUEUE)
+ EXIT_CLEANLY();
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+void BPF_STRUCT_OPS(exit_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (exit_point == EXIT_DISPATCH)
+ EXIT_CLEANLY();
+
+ scx_bpf_consume(SCX_DSQ_GLOBAL);
+}
+
+void BPF_STRUCT_OPS(exit_enable, struct task_struct *p)
+{
+ if (exit_point == EXIT_ENABLE)
+ EXIT_CLEANLY();
+}
+
+s32 BPF_STRUCT_OPS(exit_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ if (exit_point == EXIT_INIT_TASK)
+ EXIT_CLEANLY();
+
+ return 0;
+}
+
+void BPF_STRUCT_OPS(exit_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(exit_init)
+{
+ if (exit_point == EXIT_INIT)
+ EXIT_CLEANLY();
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops exit_ops = {
+ .select_cpu = exit_select_cpu,
+ .enqueue = exit_enqueue,
+ .dispatch = exit_dispatch,
+ .init_task = exit_init_task,
+ .enable = exit_enable,
+ .exit = exit_exit,
+ .init = exit_init,
+ .name = "exit",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/exit.c b/tools/testing/selftests/sched_ext/exit.c
new file mode 100644
index 000000000000..31bcd06e21cd
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit.c
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "exit.bpf.skel.h"
+#include "scx_test.h"
+
+#include "exit_test.h"
+
+static enum scx_test_status run(void *ctx)
+{
+ enum exit_test_case tc;
+
+ for (tc = 0; tc < NUM_EXITS; tc++) {
+ struct exit *skel;
+ struct bpf_link *link;
+ char buf[16];
+
+ skel = exit__open();
+ skel->rodata->exit_point = tc;
+ exit__load(skel);
+ link = bpf_map__attach_struct_ops(skel->maps.exit_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ exit__destroy(skel);
+ return SCX_TEST_FAIL;
+ }
+
+ /* Assumes uei.kind is written last */
+ while (skel->data->uei.kind == EXIT_KIND(SCX_EXIT_NONE))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG_BPF));
+ SCX_EQ(skel->data->uei.exit_code, tc);
+ sprintf(buf, "%d", tc);
+ SCX_ASSERT(!strcmp(skel->data->uei.msg, buf));
+ bpf_link__destroy(link);
+ exit__destroy(skel);
+ }
+
+ return SCX_TEST_PASS;
+}
+
+struct scx_test exit_test = {
+ .name = "exit",
+ .description = "Verify we can cleanly exit a scheduler in multiple places",
+ .run = run,
+};
+REGISTER_SCX_TEST(&exit_test)
diff --git a/tools/testing/selftests/sched_ext/exit_test.h b/tools/testing/selftests/sched_ext/exit_test.h
new file mode 100644
index 000000000000..94f0268b9cb8
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit_test.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __EXIT_TEST_H__
+#define __EXIT_TEST_H__
+
+enum exit_test_case {
+ EXIT_SELECT_CPU,
+ EXIT_ENQUEUE,
+ EXIT_DISPATCH,
+ EXIT_ENABLE,
+ EXIT_INIT_TASK,
+ EXIT_INIT,
+ NUM_EXITS,
+};
+
+#endif // # __EXIT_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/hotplug.bpf.c b/tools/testing/selftests/sched_ext/hotplug.bpf.c
new file mode 100644
index 000000000000..8f2601db39f3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug.bpf.c
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+#include "hotplug_test.h"
+
+UEI_DEFINE(uei);
+
+void BPF_STRUCT_OPS(hotplug_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+static void exit_from_hotplug(s32 cpu, bool onlining)
+{
+ /*
+ * Ignored, just used to verify that we can invoke blocking kfuncs
+ * from the hotplug path.
+ */
+ scx_bpf_create_dsq(0, -1);
+
+ s64 code = SCX_ECODE_ACT_RESTART | HOTPLUG_EXIT_RSN;
+
+ if (onlining)
+ code |= HOTPLUG_ONLINING;
+
+ scx_bpf_exit(code, "hotplug event detected (%d going %s)", cpu,
+ onlining ? "online" : "offline");
+}
+
+void BPF_STRUCT_OPS_SLEEPABLE(hotplug_cpu_online, s32 cpu)
+{
+ exit_from_hotplug(cpu, true);
+}
+
+void BPF_STRUCT_OPS_SLEEPABLE(hotplug_cpu_offline, s32 cpu)
+{
+ exit_from_hotplug(cpu, false);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops hotplug_cb_ops = {
+ .cpu_online = hotplug_cpu_online,
+ .cpu_offline = hotplug_cpu_offline,
+ .exit = hotplug_exit,
+ .name = "hotplug_cbs",
+ .timeout_ms = 1000U,
+};
+
+SEC(".struct_ops.link")
+struct sched_ext_ops hotplug_nocb_ops = {
+ .exit = hotplug_exit,
+ .name = "hotplug_nocbs",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/hotplug.c b/tools/testing/selftests/sched_ext/hotplug.c
new file mode 100644
index 000000000000..87bf220b1bce
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug.c
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sched.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "hotplug_test.h"
+#include "hotplug.bpf.skel.h"
+#include "scx_test.h"
+#include "util.h"
+
+const char *online_path = "/sys/devices/system/cpu/cpu1/online";
+
+static bool is_cpu_online(void)
+{
+ return file_read_long(online_path) > 0;
+}
+
+static void toggle_online_status(bool online)
+{
+ long val = online ? 1 : 0;
+ int ret;
+
+ ret = file_write_long(online_path, val);
+ if (ret != 0)
+ fprintf(stderr, "Failed to bring CPU %s (%s)",
+ online ? "online" : "offline", strerror(errno));
+}
+
+static enum scx_test_status setup(void **ctx)
+{
+ if (!is_cpu_online())
+ return SCX_TEST_SKIP;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status test_hotplug(bool onlining, bool cbs_defined)
+{
+ struct hotplug *skel;
+ struct bpf_link *link;
+ long kind, code;
+
+ SCX_ASSERT(is_cpu_online());
+
+ skel = hotplug__open_and_load();
+ SCX_ASSERT(skel);
+
+ /* Testing the offline -> online path, so go offline before starting */
+ if (onlining)
+ toggle_online_status(0);
+
+ if (cbs_defined) {
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_BPF);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) | HOTPLUG_EXIT_RSN;
+ if (onlining)
+ code |= HOTPLUG_ONLINING;
+ } else {
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
+ SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
+ }
+
+ if (cbs_defined)
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_cb_ops);
+ else
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
+
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ hotplug__destroy(skel);
+ return SCX_TEST_FAIL;
+ }
+
+ toggle_online_status(onlining ? 1 : 0);
+
+ while (!UEI_EXITED(skel, uei))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, kind);
+ SCX_EQ(UEI_REPORT(skel, uei), code);
+
+ if (!onlining)
+ toggle_online_status(1);
+
+ bpf_link__destroy(link);
+ hotplug__destroy(skel);
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status test_hotplug_attach(void)
+{
+ struct hotplug *skel;
+ struct bpf_link *link;
+ enum scx_test_status status = SCX_TEST_PASS;
+ long kind, code;
+
+ SCX_ASSERT(is_cpu_online());
+ SCX_ASSERT(scx_hotplug_seq() > 0);
+
+ skel = SCX_OPS_OPEN(hotplug_nocb_ops, hotplug);
+ SCX_ASSERT(skel);
+
+ SCX_OPS_LOAD(skel, hotplug_nocb_ops, hotplug, uei);
+
+ /*
+ * Take the CPU offline to increment the global hotplug seq, which
+ * should cause attach to fail due to us setting the hotplug seq above
+ */
+ toggle_online_status(0);
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
+
+ toggle_online_status(1);
+
+ SCX_ASSERT(link);
+ while (!UEI_EXITED(skel, uei))
+ sched_yield();
+
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
+ SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
+ SCX_EQ(skel->data->uei.kind, kind);
+ SCX_EQ(UEI_REPORT(skel, uei), code);
+
+ bpf_link__destroy(link);
+ hotplug__destroy(skel);
+
+ return status;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+
+#define HP_TEST(__onlining, __cbs_defined) ({ \
+ if (test_hotplug(__onlining, __cbs_defined) != SCX_TEST_PASS) \
+ return SCX_TEST_FAIL; \
+})
+
+ HP_TEST(true, true);
+ HP_TEST(false, true);
+ HP_TEST(true, false);
+ HP_TEST(false, false);
+
+#undef HP_TEST
+
+ return test_hotplug_attach();
+}
+
+static void cleanup(void *ctx)
+{
+ toggle_online_status(1);
+}
+
+struct scx_test hotplug_test = {
+ .name = "hotplug",
+ .description = "Verify hotplug behavior",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&hotplug_test)
diff --git a/tools/testing/selftests/sched_ext/hotplug_test.h b/tools/testing/selftests/sched_ext/hotplug_test.h
new file mode 100644
index 000000000000..73d236f90787
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug_test.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __HOTPLUG_TEST_H__
+#define __HOTPLUG_TEST_H__
+
+enum hotplug_test_flags {
+ HOTPLUG_EXIT_RSN = 1LLU << 0,
+ HOTPLUG_ONLINING = 1LLU << 1,
+};
+
+#endif // # __HOTPLUG_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/init_enable_count.bpf.c b/tools/testing/selftests/sched_ext/init_enable_count.bpf.c
new file mode 100644
index 000000000000..47ea89a626c3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/init_enable_count.bpf.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that verifies that we do proper counting of init, enable, etc
+ * callbacks.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 init_task_cnt, exit_task_cnt, enable_cnt, disable_cnt;
+u64 init_fork_cnt, init_transition_cnt;
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(cnt_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ __sync_fetch_and_add(&init_task_cnt, 1);
+
+ if (args->fork)
+ __sync_fetch_and_add(&init_fork_cnt, 1);
+ else
+ __sync_fetch_and_add(&init_transition_cnt, 1);
+
+ return 0;
+}
+
+void BPF_STRUCT_OPS(cnt_exit_task, struct task_struct *p)
+{
+ __sync_fetch_and_add(&exit_task_cnt, 1);
+}
+
+void BPF_STRUCT_OPS(cnt_enable, struct task_struct *p)
+{
+ __sync_fetch_and_add(&enable_cnt, 1);
+}
+
+void BPF_STRUCT_OPS(cnt_disable, struct task_struct *p)
+{
+ __sync_fetch_and_add(&disable_cnt, 1);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops init_enable_count_ops = {
+ .init_task = cnt_init_task,
+ .exit_task = cnt_exit_task,
+ .enable = cnt_enable,
+ .disable = cnt_disable,
+ .name = "init_enable_count",
+};
diff --git a/tools/testing/selftests/sched_ext/init_enable_count.c b/tools/testing/selftests/sched_ext/init_enable_count.c
new file mode 100644
index 000000000000..97d45f1e5597
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/init_enable_count.c
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <sched.h>
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include "scx_test.h"
+#include "init_enable_count.bpf.skel.h"
+
+#define SCHED_EXT 7
+
+static struct init_enable_count *
+open_load_prog(bool global)
+{
+ struct init_enable_count *skel;
+
+ skel = init_enable_count__open();
+ SCX_BUG_ON(!skel, "Failed to open skel");
+
+ if (!global)
+ skel->struct_ops.init_enable_count_ops->flags |= SCX_OPS_SWITCH_PARTIAL;
+
+ SCX_BUG_ON(init_enable_count__load(skel), "Failed to load skel");
+
+ return skel;
+}
+
+static enum scx_test_status run_test(bool global)
+{
+ struct init_enable_count *skel;
+ struct bpf_link *link;
+ const u32 num_children = 5, num_pre_forks = 1024;
+ int ret, i, status;
+ struct sched_param param = {};
+ pid_t pids[num_pre_forks];
+
+ skel = open_load_prog(global);
+
+ /*
+ * Fork a bunch of children before we attach the scheduler so that we
+ * ensure (at least in practical terms) that there are more tasks that
+ * transition from SCHED_OTHER -> SCHED_EXT than there are tasks that
+ * take the fork() path either below or in other processes.
+ */
+ for (i = 0; i < num_pre_forks; i++) {
+ pids[i] = fork();
+ SCX_FAIL_IF(pids[i] < 0, "Failed to fork child");
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ link = bpf_map__attach_struct_ops(skel->maps.init_enable_count_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ for (i = 0; i < num_pre_forks; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for pre-forked child\n");
+
+ SCX_FAIL_IF(status != 0, "Pre-forked child %d exited with status %d\n", i,
+ status);
+ }
+
+ bpf_link__destroy(link);
+ SCX_GE(skel->bss->init_task_cnt, num_pre_forks);
+ SCX_GE(skel->bss->exit_task_cnt, num_pre_forks);
+
+ link = bpf_map__attach_struct_ops(skel->maps.init_enable_count_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ /* SCHED_EXT children */
+ for (i = 0; i < num_children; i++) {
+ pids[i] = fork();
+ SCX_FAIL_IF(pids[i] < 0, "Failed to fork child");
+
+ if (pids[i] == 0) {
+ ret = sched_setscheduler(0, SCHED_EXT, ¶m);
+ SCX_BUG_ON(ret, "Failed to set sched to sched_ext");
+
+ /*
+ * Reset to SCHED_OTHER for half of them. Counts for
+ * everything should still be the same regardless, as
+ * ops.disable() is invoked even if a task is still on
+ * SCHED_EXT before it exits.
+ */
+ if (i % 2 == 0) {
+ ret = sched_setscheduler(0, SCHED_OTHER, ¶m);
+ SCX_BUG_ON(ret, "Failed to reset sched to normal");
+ }
+ exit(0);
+ }
+ }
+ for (i = 0; i < num_children; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for SCX child\n");
+
+ SCX_FAIL_IF(status != 0, "SCX child %d exited with status %d\n", i,
+ status);
+ }
+
+ /* SCHED_OTHER children */
+ for (i = 0; i < num_children; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0)
+ exit(0);
+ }
+
+ for (i = 0; i < num_children; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for normal child\n");
+
+ SCX_FAIL_IF(status != 0, "Normal child %d exited with status %d\n", i,
+ status);
+ }
+
+ bpf_link__destroy(link);
+
+ SCX_GE(skel->bss->init_task_cnt, 2 * num_children);
+ SCX_GE(skel->bss->exit_task_cnt, 2 * num_children);
+
+ if (global) {
+ SCX_GE(skel->bss->enable_cnt, 2 * num_children);
+ SCX_GE(skel->bss->disable_cnt, 2 * num_children);
+ } else {
+ SCX_EQ(skel->bss->enable_cnt, num_children);
+ SCX_EQ(skel->bss->disable_cnt, num_children);
+ }
+ /*
+ * We forked a ton of tasks before we attached the scheduler above, so
+ * this should be fine. Technically it could be flaky if a ton of forks
+ * are happening at the same time in other processes, but that should
+ * be exceedingly unlikely.
+ */
+ SCX_GT(skel->bss->init_transition_cnt, skel->bss->init_fork_cnt);
+ SCX_GE(skel->bss->init_fork_cnt, 2 * num_children);
+
+ init_enable_count__destroy(skel);
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ enum scx_test_status status;
+
+ status = run_test(true);
+ if (status != SCX_TEST_PASS)
+ return status;
+
+ return run_test(false);
+}
+
+struct scx_test init_enable_count = {
+ .name = "init_enable_count",
+ .description = "Verify we do the correct amount of counting of init, "
+ "enable, etc callbacks.",
+ .run = run,
+};
+REGISTER_SCX_TEST(&init_enable_count)
diff --git a/tools/testing/selftests/sched_ext/maximal.bpf.c b/tools/testing/selftests/sched_ext/maximal.bpf.c
new file mode 100644
index 000000000000..44612fdaf399
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maximal.bpf.c
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler with every callback defined.
+ *
+ * This scheduler defines every callback.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+s32 BPF_STRUCT_OPS(maximal_select_cpu, struct task_struct *p, s32 prev_cpu,
+ u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(maximal_enqueue, struct task_struct *p, u64 enq_flags)
+{
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+void BPF_STRUCT_OPS(maximal_dequeue, struct task_struct *p, u64 deq_flags)
+{}
+
+void BPF_STRUCT_OPS(maximal_dispatch, s32 cpu, struct task_struct *prev)
+{
+ scx_bpf_consume(SCX_DSQ_GLOBAL);
+}
+
+void BPF_STRUCT_OPS(maximal_runnable, struct task_struct *p, u64 enq_flags)
+{}
+
+void BPF_STRUCT_OPS(maximal_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maximal_stopping, struct task_struct *p, bool runnable)
+{}
+
+void BPF_STRUCT_OPS(maximal_quiescent, struct task_struct *p, u64 deq_flags)
+{}
+
+bool BPF_STRUCT_OPS(maximal_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ return false;
+}
+
+bool BPF_STRUCT_OPS(maximal_core_sched_before, struct task_struct *a,
+ struct task_struct *b)
+{
+ return false;
+}
+
+void BPF_STRUCT_OPS(maximal_set_weight, struct task_struct *p, u32 weight)
+{}
+
+void BPF_STRUCT_OPS(maximal_set_cpumask, struct task_struct *p,
+ const struct cpumask *cpumask)
+{}
+
+void BPF_STRUCT_OPS(maximal_update_idle, s32 cpu, bool idle)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_acquire, s32 cpu,
+ struct scx_cpu_acquire_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_release, s32 cpu,
+ struct scx_cpu_release_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_online, s32 cpu)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_offline, s32 cpu)
+{}
+
+s32 BPF_STRUCT_OPS(maximal_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_enable, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maximal_exit_task, struct task_struct *p,
+ struct scx_exit_task_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_disable, struct task_struct *p)
+{}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(maximal_init)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_exit, struct scx_exit_info *info)
+{}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maximal_ops = {
+ .select_cpu = maximal_select_cpu,
+ .enqueue = maximal_enqueue,
+ .dequeue = maximal_dequeue,
+ .dispatch = maximal_dispatch,
+ .runnable = maximal_runnable,
+ .running = maximal_running,
+ .stopping = maximal_stopping,
+ .quiescent = maximal_quiescent,
+ .yield = maximal_yield,
+ .core_sched_before = maximal_core_sched_before,
+ .set_weight = maximal_set_weight,
+ .set_cpumask = maximal_set_cpumask,
+ .update_idle = maximal_update_idle,
+ .cpu_acquire = maximal_cpu_acquire,
+ .cpu_release = maximal_cpu_release,
+ .cpu_online = maximal_cpu_online,
+ .cpu_offline = maximal_cpu_offline,
+ .init_task = maximal_init_task,
+ .enable = maximal_enable,
+ .exit_task = maximal_exit_task,
+ .disable = maximal_disable,
+ .init = maximal_init,
+ .exit = maximal_exit,
+ .name = "maximal",
+};
diff --git a/tools/testing/selftests/sched_ext/maximal.c b/tools/testing/selftests/sched_ext/maximal.c
new file mode 100644
index 000000000000..f38fc973c380
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maximal.c
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maximal.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct maximal *skel;
+
+ skel = maximal__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct maximal *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.maximal_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct maximal *skel = ctx;
+
+ maximal__destroy(skel);
+}
+
+struct scx_test maximal = {
+ .name = "maximal",
+ .description = "Verify we can load a scheduler with every callback defined",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&maximal)
diff --git a/tools/testing/selftests/sched_ext/maybe_null.bpf.c b/tools/testing/selftests/sched_ext/maybe_null.bpf.c
new file mode 100644
index 000000000000..27d0f386acfb
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.bpf.c
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maybe_null_success_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (p != NULL)
+ vtime_test = p->scx.dsq_vtime;
+}
+
+bool BPF_STRUCT_OPS(maybe_null_success_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ if (to)
+ bpf_printk("Yielding to %s[%d]", to->comm, to->pid);
+
+ return false;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_success = {
+ .dispatch = maybe_null_success_dispatch,
+ .yield = maybe_null_success_yield,
+ .enable = maybe_null_running,
+ .name = "minimal",
+};
diff --git a/tools/testing/selftests/sched_ext/maybe_null.c b/tools/testing/selftests/sched_ext/maybe_null.c
new file mode 100644
index 000000000000..31cfafb0cf65
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.c
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maybe_null.bpf.skel.h"
+#include "maybe_null_fail_dsp.bpf.skel.h"
+#include "maybe_null_fail_yld.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status run(void *ctx)
+{
+ struct maybe_null *skel;
+ struct maybe_null_fail_dsp *fail_dsp;
+ struct maybe_null_fail_yld *fail_yld;
+
+ skel = maybe_null__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load maybe_null skel");
+ return SCX_TEST_FAIL;
+ }
+ maybe_null__destroy(skel);
+
+ fail_dsp = maybe_null_fail_dsp__open_and_load();
+ if (fail_dsp) {
+ maybe_null_fail_dsp__destroy(fail_dsp);
+ SCX_ERR("Should failed to open and load maybe_null_fail_dsp skel");
+ return SCX_TEST_FAIL;
+ }
+
+ fail_yld = maybe_null_fail_yld__open_and_load();
+ if (fail_yld) {
+ maybe_null_fail_yld__destroy(fail_yld);
+ SCX_ERR("Should failed to open and load maybe_null_fail_yld skel");
+ return SCX_TEST_FAIL;
+ }
+
+ return SCX_TEST_PASS;
+}
+
+struct scx_test maybe_null = {
+ .name = "maybe_null",
+ .description = "Verify if PTR_MAYBE_NULL work for .dispatch",
+ .run = run,
+};
+REGISTER_SCX_TEST(&maybe_null)
diff --git a/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c b/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
new file mode 100644
index 000000000000..c0641050271d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maybe_null_fail_dispatch, s32 cpu, struct task_struct *p)
+{
+ vtime_test = p->scx.dsq_vtime;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_fail = {
+ .dispatch = maybe_null_fail_dispatch,
+ .enable = maybe_null_running,
+ .name = "maybe_null_fail_dispatch",
+};
diff --git a/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c b/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
new file mode 100644
index 000000000000..3c1740028e3b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+bool BPF_STRUCT_OPS(maybe_null_fail_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ bpf_printk("Yielding to %s[%d]", to->comm, to->pid);
+
+ return false;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_fail = {
+ .yield = maybe_null_fail_yield,
+ .enable = maybe_null_running,
+ .name = "maybe_null_fail_yield",
+};
diff --git a/tools/testing/selftests/sched_ext/minimal.bpf.c b/tools/testing/selftests/sched_ext/minimal.bpf.c
new file mode 100644
index 000000000000..6a7eccef0104
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/minimal.bpf.c
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A completely minimal scheduler.
+ *
+ * This scheduler defines the absolute minimal set of struct sched_ext_ops
+ * fields: its name. It should _not_ fail to be loaded, and can be used to
+ * exercise the default scheduling paths in ext.c.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+SEC(".struct_ops.link")
+struct sched_ext_ops minimal_ops = {
+ .name = "minimal",
+};
diff --git a/tools/testing/selftests/sched_ext/minimal.c b/tools/testing/selftests/sched_ext/minimal.c
new file mode 100644
index 000000000000..6c5db8ebbf8a
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/minimal.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "minimal.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct minimal *skel;
+
+ skel = minimal__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct minimal *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.minimal_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct minimal *skel = ctx;
+
+ minimal__destroy(skel);
+}
+
+struct scx_test minimal = {
+ .name = "minimal",
+ .description = "Verify we can load a fully minimal scheduler",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&minimal)
diff --git a/tools/testing/selftests/sched_ext/prog_run.bpf.c b/tools/testing/selftests/sched_ext/prog_run.bpf.c
new file mode 100644
index 000000000000..fd2c8f12af16
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/prog_run.bpf.c
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates that we can invoke sched_ext kfuncs in
+ * BPF_PROG_TYPE_SYSCALL programs.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+UEI_DEFINE(uei);
+
+char _license[] SEC("license") = "GPL";
+
+SEC("syscall")
+int BPF_PROG(prog_run_syscall)
+{
+ scx_bpf_exit(0xdeadbeef, "Exited from PROG_RUN");
+ return 0;
+}
+
+void BPF_STRUCT_OPS(prog_run_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops prog_run_ops = {
+ .exit = prog_run_exit,
+ .name = "prog_run",
+};
diff --git a/tools/testing/selftests/sched_ext/prog_run.c b/tools/testing/selftests/sched_ext/prog_run.c
new file mode 100644
index 000000000000..3cd57ef8daaa
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/prog_run.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "prog_run.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct prog_run *skel;
+
+ skel = prog_run__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct prog_run *skel = ctx;
+ struct bpf_link *link;
+ int prog_fd, err = 0;
+
+ prog_fd = bpf_program__fd(skel->progs.prog_run_syscall);
+ if (prog_fd < 0) {
+ SCX_ERR("Failed to get BPF_PROG_RUN prog");
+ return SCX_TEST_FAIL;
+ }
+
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+ link = bpf_map__attach_struct_ops(skel->maps.prog_run_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ close(prog_fd);
+ return SCX_TEST_FAIL;
+ }
+
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ SCX_EQ(err, 0);
+
+ /* Assumes uei.kind is written last */
+ while (skel->data->uei.kind == EXIT_KIND(SCX_EXIT_NONE))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG_BPF));
+ SCX_EQ(skel->data->uei.exit_code, 0xdeadbeef);
+ close(prog_fd);
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct prog_run *skel = ctx;
+
+ prog_run__destroy(skel);
+}
+
+struct scx_test prog_run = {
+ .name = "prog_run",
+ .description = "Verify we can call into a scheduler with BPF_PROG_RUN, and invoke kfuncs",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&prog_run)
diff --git a/tools/testing/selftests/sched_ext/reload_loop.c b/tools/testing/selftests/sched_ext/reload_loop.c
new file mode 100644
index 000000000000..5cfba2d6e056
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/reload_loop.c
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <pthread.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maximal.bpf.skel.h"
+#include "scx_test.h"
+
+static struct maximal *skel;
+static pthread_t threads[2];
+
+bool force_exit = false;
+
+static enum scx_test_status setup(void **ctx)
+{
+ skel = maximal__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+
+ return SCX_TEST_PASS;
+}
+
+static void *do_reload_loop(void *arg)
+{
+ u32 i;
+
+ for (i = 0; i < 1024 && !force_exit; i++) {
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.maximal_ops);
+ if (link)
+ bpf_link__destroy(link);
+ }
+
+ return NULL;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ int err;
+ void *ret;
+
+ err = pthread_create(&threads[0], NULL, do_reload_loop, NULL);
+ SCX_FAIL_IF(err, "Failed to create thread 0");
+
+ err = pthread_create(&threads[1], NULL, do_reload_loop, NULL);
+ SCX_FAIL_IF(err, "Failed to create thread 1");
+
+ SCX_FAIL_IF(pthread_join(threads[0], &ret), "thread 0 failed");
+ SCX_FAIL_IF(pthread_join(threads[1], &ret), "thread 1 failed");
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ force_exit = true;
+ maximal__destroy(skel);
+}
+
+struct scx_test reload_loop = {
+ .name = "reload_loop",
+ .description = "Stress test loading and unloading schedulers repeatedly in a tight loop",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&reload_loop)
diff --git a/tools/testing/selftests/sched_ext/runner.c b/tools/testing/selftests/sched_ext/runner.c
new file mode 100644
index 000000000000..eab48c7ff309
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/runner.c
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <libgen.h>
+#include <bpf/bpf.h>
+#include "scx_test.h"
+
+const char help_fmt[] =
+"The runner for sched_ext tests.\n"
+"\n"
+"The runner is statically linked against all testcases, and runs them all serially.\n"
+"It's required for the testcases to be serial, as only a single host-wide sched_ext\n"
+"scheduler may be loaded at any given time."
+"\n"
+"Usage: %s [-t TEST] [-h]\n"
+"\n"
+" -t TEST Only run tests whose name includes this string\n"
+" -s Include print output for skipped tests\n"
+" -q Don't print the test descriptions during run\n"
+" -h Display this help and exit\n";
+
+static volatile int exit_req;
+static bool quiet, print_skipped;
+
+#define MAX_SCX_TESTS 2048
+
+static struct scx_test __scx_tests[MAX_SCX_TESTS];
+static unsigned __scx_num_tests = 0;
+
+static void sigint_handler(int simple)
+{
+ exit_req = 1;
+}
+
+static void print_test_preamble(const struct scx_test *test, bool quiet)
+{
+ printf("===== START =====\n");
+ printf("TEST: %s\n", test->name);
+ if (!quiet)
+ printf("DESCRIPTION: %s\n", test->description);
+ printf("OUTPUT:\n");
+}
+
+static const char *status_to_result(enum scx_test_status status)
+{
+ switch (status) {
+ case SCX_TEST_PASS:
+ case SCX_TEST_SKIP:
+ return "ok";
+ case SCX_TEST_FAIL:
+ return "not ok";
+ default:
+ return "<UNKNOWN>";
+ }
+}
+
+static void print_test_result(const struct scx_test *test,
+ enum scx_test_status status,
+ unsigned int testnum)
+{
+ const char *result = status_to_result(status);
+ const char *directive = status == SCX_TEST_SKIP ? "SKIP " : "";
+
+ printf("%s %u %s # %s\n", result, testnum, test->name, directive);
+ printf("===== END =====\n");
+}
+
+static bool should_skip_test(const struct scx_test *test, const char * filter)
+{
+ return !strstr(test->name, filter);
+}
+
+static enum scx_test_status run_test(const struct scx_test *test)
+{
+ enum scx_test_status status;
+ void *context = NULL;
+
+ if (test->setup) {
+ status = test->setup(&context);
+ if (status != SCX_TEST_PASS)
+ return status;
+ }
+
+ status = test->run(context);
+
+ if (test->cleanup)
+ test->cleanup(context);
+
+ return status;
+}
+
+static bool test_valid(const struct scx_test *test)
+{
+ if (!test) {
+ fprintf(stderr, "NULL test detected\n");
+ return false;
+ }
+
+ if (!test->name) {
+ fprintf(stderr,
+ "Test with no name found. Must specify test name.\n");
+ return false;
+ }
+
+ if (!test->description) {
+ fprintf(stderr, "Test %s requires description.\n", test->name);
+ return false;
+ }
+
+ if (!test->run) {
+ fprintf(stderr, "Test %s has no run() callback\n", test->name);
+ return false;
+ }
+
+ return true;
+}
+
+int main(int argc, char **argv)
+{
+ const char *filter = NULL;
+ unsigned testnum = 0, i;
+ unsigned passed = 0, skipped = 0, failed = 0;
+ int opt;
+
+ signal(SIGINT, sigint_handler);
+ signal(SIGTERM, sigint_handler);
+
+ libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+
+ while ((opt = getopt(argc, argv, "qst:h")) != -1) {
+ switch (opt) {
+ case 'q':
+ quiet = true;
+ break;
+ case 's':
+ print_skipped = true;
+ break;
+ case 't':
+ filter = optarg;
+ break;
+ default:
+ fprintf(stderr, help_fmt, basename(argv[0]));
+ return opt != 'h';
+ }
+ }
+
+ for (i = 0; i < __scx_num_tests; i++) {
+ enum scx_test_status status;
+ struct scx_test *test = &__scx_tests[i];
+
+ if (filter && should_skip_test(test, filter)) {
+ /*
+ * Printing the skipped tests and their preambles can
+ * add a lot of noise to the runner output. Printing
+ * this is only really useful for CI, so let's skip it
+ * by default.
+ */
+ if (print_skipped) {
+ print_test_preamble(test, quiet);
+ print_test_result(test, SCX_TEST_SKIP, ++testnum);
+ }
+ continue;
+ }
+
+ print_test_preamble(test, quiet);
+ status = run_test(test);
+ print_test_result(test, status, ++testnum);
+ switch (status) {
+ case SCX_TEST_PASS:
+ passed++;
+ break;
+ case SCX_TEST_SKIP:
+ skipped++;
+ break;
+ case SCX_TEST_FAIL:
+ failed++;
+ break;
+ }
+ }
+ printf("\n\n=============================\n\n");
+ printf("RESULTS:\n\n");
+ printf("PASSED: %u\n", passed);
+ printf("SKIPPED: %u\n", skipped);
+ printf("FAILED: %u\n", failed);
+
+ return 0;
+}
+
+void scx_test_register(struct scx_test *test)
+{
+ SCX_BUG_ON(!test_valid(test), "Invalid test found");
+ SCX_BUG_ON(__scx_num_tests >= MAX_SCX_TESTS, "Maximum tests exceeded");
+
+ __scx_tests[__scx_num_tests++] = *test;
+}
diff --git a/tools/testing/selftests/sched_ext/scx_test.h b/tools/testing/selftests/sched_ext/scx_test.h
new file mode 100644
index 000000000000..90b8d6915bb7
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/scx_test.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __SCX_TEST_H__
+#define __SCX_TEST_H__
+
+#include <errno.h>
+#include <scx/common.h>
+#include <scx/compat.h>
+
+enum scx_test_status {
+ SCX_TEST_PASS = 0,
+ SCX_TEST_SKIP,
+ SCX_TEST_FAIL,
+};
+
+#define EXIT_KIND(__ent) __COMPAT_ENUM_OR_ZERO("scx_exit_kind", #__ent)
+
+struct scx_test {
+ /**
+ * name - The name of the testcase.
+ */
+ const char *name;
+
+ /**
+ * description - A description of your testcase: what it tests and is
+ * meant to validate.
+ */
+ const char *description;
+
+ /*
+ * setup - Setup the test.
+ * @ctx: A pointer to a context object that will be passed to run and
+ * cleanup.
+ *
+ * An optional callback that allows a testcase to perform setup for its
+ * run. A test may return SCX_TEST_SKIP to skip the run.
+ */
+ enum scx_test_status (*setup)(void **ctx);
+
+ /*
+ * run - Run the test.
+ * @ctx: Context set in the setup() callback. If @ctx was not set in
+ * setup(), it is NULL.
+ *
+ * The main test. Callers should return one of:
+ *
+ * - SCX_TEST_PASS: Test passed
+ * - SCX_TEST_SKIP: Test should be skipped
+ * - SCX_TEST_FAIL: Test failed
+ *
+ * This callback must be defined.
+ */
+ enum scx_test_status (*run)(void *ctx);
+
+ /*
+ * cleanup - Perform cleanup following the test
+ * @ctx: Context set in the setup() callback. If @ctx was not set in
+ * setup(), it is NULL.
+ *
+ * An optional callback that allows a test to perform cleanup after
+ * being run. This callback is run even if the run() callback returns
+ * SCX_TEST_SKIP or SCX_TEST_FAIL. It is not run if setup() returns
+ * SCX_TEST_SKIP or SCX_TEST_FAIL.
+ */
+ void (*cleanup)(void *ctx);
+};
+
+void scx_test_register(struct scx_test *test);
+
+#define REGISTER_SCX_TEST(__test) \
+ __attribute__((constructor)) \
+ static void ___scxregister##__LINE__(void) \
+ { \
+ scx_test_register(__test); \
+ }
+
+#define SCX_ERR(__fmt, ...) \
+ do { \
+ fprintf(stderr, "ERR: %s:%d\n", __FILE__, __LINE__); \
+ fprintf(stderr, __fmt"\n", ##__VA_ARGS__); \
+ } while (0)
+
+#define SCX_FAIL(__fmt, ...) \
+ do { \
+ SCX_ERR(__fmt, ##__VA_ARGS__); \
+ return SCX_TEST_FAIL; \
+ } while (0)
+
+#define SCX_FAIL_IF(__cond, __fmt, ...) \
+ do { \
+ if (__cond) \
+ SCX_FAIL(__fmt, ##__VA_ARGS__); \
+ } while (0)
+
+#define SCX_GT(_x, _y) SCX_FAIL_IF((_x) <= (_y), "Expected %s > %s (%lu > %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_GE(_x, _y) SCX_FAIL_IF((_x) < (_y), "Expected %s >= %s (%lu >= %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_LT(_x, _y) SCX_FAIL_IF((_x) >= (_y), "Expected %s < %s (%lu < %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_LE(_x, _y) SCX_FAIL_IF((_x) > (_y), "Expected %s <= %s (%lu <= %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_EQ(_x, _y) SCX_FAIL_IF((_x) != (_y), "Expected %s == %s (%lu == %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_ASSERT(_x) SCX_FAIL_IF(!(_x), "Expected %s to be true (%lu)", \
+ #_x, (u64)(_x))
+
+#define SCX_ECODE_VAL(__ecode) ({ \
+ u64 __val = 0; \
+ bool __found = false; \
+ \
+ __found = __COMPAT_read_enum("scx_exit_code", #__ecode, &__val); \
+ SCX_ASSERT(__found); \
+ (s64)__val; \
+})
+
+#define SCX_KIND_VAL(__kind) ({ \
+ u64 __val = 0; \
+ bool __found = false; \
+ \
+ __found = __COMPAT_read_enum("scx_exit_kind", #__kind, &__val); \
+ SCX_ASSERT(__found); \
+ __val; \
+})
+
+#endif // # __SCX_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
new file mode 100644
index 000000000000..2ed2991afafe
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+bool saw_local = false;
+
+static bool task_is_test(const struct task_struct *p)
+{
+ return !bpf_strncmp(p->comm, 9, "select_cpu");
+}
+
+void BPF_STRUCT_OPS(select_cpu_dfl_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ const struct cpumask *idle_mask = scx_bpf_get_idle_cpumask();
+
+ if (task_is_test(p) &&
+ bpf_cpumask_test_cpu(scx_bpf_task_cpu(p), idle_mask)) {
+ saw_local = true;
+ }
+ scx_bpf_put_idle_cpumask(idle_mask);
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dfl_ops = {
+ .enqueue = select_cpu_dfl_enqueue,
+ .name = "select_cpu_dfl",
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl.c b/tools/testing/selftests/sched_ext/select_cpu_dfl.c
new file mode 100644
index 000000000000..a53a40c2d2f0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl.c
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dfl.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dfl *skel;
+
+ skel = select_cpu_dfl__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dfl *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dfl_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ SCX_ASSERT(!skel->bss->saw_local);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dfl *skel = ctx;
+
+ select_cpu_dfl__destroy(skel);
+}
+
+struct scx_test select_cpu_dfl = {
+ .name = "select_cpu_dfl",
+ .description = "Verify the default ops.select_cpu() dispatches tasks "
+ "when idles cores are found, and skips ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dfl)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
new file mode 100644
index 000000000000..4bb5abb2d369
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation, and with the SCX_OPS_ENQ_DFL_NO_DISPATCH ops flag
+ * specified.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+bool saw_local = false;
+
+/* Per-task scheduling context */
+struct task_ctx {
+ bool force_local; /* CPU changed by ops.select_cpu() */
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
+ __uint(map_flags, BPF_F_NO_PREALLOC);
+ __type(key, int);
+ __type(value, struct task_ctx);
+} task_ctx_stor SEC(".maps");
+
+/* Manually specify the signature until the kfunc is added to the scx repo. */
+s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
+ bool *found) __ksym;
+
+s32 BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ struct task_ctx *tctx;
+ s32 cpu;
+
+ tctx = bpf_task_storage_get(&task_ctx_stor, p, 0, 0);
+ if (!tctx) {
+ scx_bpf_error("task_ctx lookup failed");
+ return -ESRCH;
+ }
+
+ cpu = scx_bpf_select_cpu_dfl(p, prev_cpu, wake_flags,
+ &tctx->force_local);
+
+ return cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ u64 dsq_id = SCX_DSQ_GLOBAL;
+ struct task_ctx *tctx;
+
+ tctx = bpf_task_storage_get(&task_ctx_stor, p, 0, 0);
+ if (!tctx) {
+ scx_bpf_error("task_ctx lookup failed");
+ return;
+ }
+
+ if (tctx->force_local) {
+ dsq_id = SCX_DSQ_LOCAL;
+ tctx->force_local = false;
+ saw_local = true;
+ }
+
+ scx_bpf_dispatch(p, dsq_id, SCX_SLICE_DFL, enq_flags);
+}
+
+s32 BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_init_task,
+ struct task_struct *p, struct scx_init_task_args *args)
+{
+ if (bpf_task_storage_get(&task_ctx_stor, p, 0,
+ BPF_LOCAL_STORAGE_GET_F_CREATE))
+ return 0;
+ else
+ return -ENOMEM;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dfl_nodispatch_ops = {
+ .select_cpu = select_cpu_dfl_nodispatch_select_cpu,
+ .enqueue = select_cpu_dfl_nodispatch_enqueue,
+ .init_task = select_cpu_dfl_nodispatch_init_task,
+ .name = "select_cpu_dfl_nodispatch",
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
new file mode 100644
index 000000000000..1d85bf4bf3a3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dfl_nodispatch.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel;
+
+ skel = select_cpu_dfl_nodispatch__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dfl_nodispatch_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ SCX_ASSERT(skel->bss->saw_local);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel = ctx;
+
+ select_cpu_dfl_nodispatch__destroy(skel);
+}
+
+struct scx_test select_cpu_dfl_nodispatch = {
+ .name = "select_cpu_dfl_nodispatch",
+ .description = "Verify behavior of scx_bpf_select_cpu_dfl() in "
+ "ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dfl_nodispatch)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
new file mode 100644
index 000000000000..f0b96a4a04b2
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ u64 dsq_id = SCX_DSQ_LOCAL;
+ s32 cpu = prev_cpu;
+
+ if (scx_bpf_test_and_clear_cpu_idle(cpu))
+ goto dispatch;
+
+ cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+ if (cpu >= 0)
+ goto dispatch;
+
+ dsq_id = SCX_DSQ_GLOBAL;
+ cpu = prev_cpu;
+
+dispatch:
+ scx_bpf_dispatch(p, dsq_id, SCX_SLICE_DFL, 0);
+ return cpu;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_ops = {
+ .select_cpu = select_cpu_dispatch_select_cpu,
+ .name = "select_cpu_dispatch",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch.c
new file mode 100644
index 000000000000..0309ca8785b3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch.c
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch *skel;
+
+ skel = select_cpu_dispatch__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch *skel = ctx;
+
+ select_cpu_dispatch__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch = {
+ .name = "select_cpu_dispatch",
+ .description = "Test direct dispatching to built-in DSQs from "
+ "ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
new file mode 100644
index 000000000000..7b42ddce0f56
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_bad_dsq_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ /* Dispatching to a random DSQ should fail. */
+ scx_bpf_dispatch(p, 0xcafef00d, SCX_SLICE_DFL, 0);
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dispatch_bad_dsq_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_bad_dsq_ops = {
+ .select_cpu = select_cpu_dispatch_bad_dsq_select_cpu,
+ .exit = select_cpu_dispatch_bad_dsq_exit,
+ .name = "select_cpu_dispatch_bad_dsq",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
new file mode 100644
index 000000000000..47eb6ed7627d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch_bad_dsq.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel;
+
+ skel = select_cpu_dispatch_bad_dsq__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_bad_dsq_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel = ctx;
+
+ select_cpu_dispatch_bad_dsq__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch_bad_dsq = {
+ .name = "select_cpu_dispatch_bad_dsq",
+ .description = "Verify graceful failure if we direct-dispatch to a "
+ "bogus DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch_bad_dsq)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
new file mode 100644
index 000000000000..653e3dc0b4dc
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_dbl_dsp_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ /* Dispatching twice in a row is disallowed. */
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, 0);
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, 0);
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dispatch_dbl_dsp_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_dbl_dsp_ops = {
+ .select_cpu = select_cpu_dispatch_dbl_dsp_select_cpu,
+ .exit = select_cpu_dispatch_dbl_dsp_exit,
+ .name = "select_cpu_dispatch_dbl_dsp",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
new file mode 100644
index 000000000000..48ff028a3c46
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch_dbl_dsp.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel;
+
+ skel = select_cpu_dispatch_dbl_dsp__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_dbl_dsp_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel = ctx;
+
+ select_cpu_dispatch_dbl_dsp__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch_dbl_dsp = {
+ .name = "select_cpu_dispatch_dbl_dsp",
+ .description = "Verify graceful failure if we dispatch twice to a "
+ "DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch_dbl_dsp)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
new file mode 100644
index 000000000000..7f3ebf4fc2ea
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates that enqueue flags are properly stored and
+ * applied at dispatch time when a task is directly dispatched from
+ * ops.select_cpu(). We validate this by using scx_bpf_dispatch_vtime(), and
+ * making the test a very basic vtime scheduler.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+volatile bool consumed;
+
+static u64 vtime_now;
+
+#define VTIME_DSQ 0
+
+static inline bool vtime_before(u64 a, u64 b)
+{
+ return (s64)(a - b) < 0;
+}
+
+static inline u64 task_vtime(const struct task_struct *p)
+{
+ u64 vtime = p->scx.dsq_vtime;
+
+ if (vtime_before(vtime, vtime_now - SCX_SLICE_DFL))
+ return vtime_now - SCX_SLICE_DFL;
+ else
+ return vtime;
+}
+
+s32 BPF_STRUCT_OPS(select_cpu_vtime_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu;
+
+ cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+ if (cpu >= 0)
+ goto ddsp;
+
+ cpu = prev_cpu;
+ scx_bpf_test_and_clear_cpu_idle(cpu);
+ddsp:
+ scx_bpf_dispatch_vtime(p, VTIME_DSQ, SCX_SLICE_DFL, task_vtime(p), 0);
+ return cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (scx_bpf_consume(VTIME_DSQ))
+ consumed = true;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_running, struct task_struct *p)
+{
+ if (vtime_before(vtime_now, p->scx.dsq_vtime))
+ vtime_now = p->scx.dsq_vtime;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_stopping, struct task_struct *p,
+ bool runnable)
+{
+ p->scx.dsq_vtime += (SCX_SLICE_DFL - p->scx.slice) * 100 / p->scx.weight;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_enable, struct task_struct *p)
+{
+ p->scx.dsq_vtime = vtime_now;
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(select_cpu_vtime_init)
+{
+ return scx_bpf_create_dsq(VTIME_DSQ, -1);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_vtime_ops = {
+ .select_cpu = select_cpu_vtime_select_cpu,
+ .dispatch = select_cpu_vtime_dispatch,
+ .running = select_cpu_vtime_running,
+ .stopping = select_cpu_vtime_stopping,
+ .enable = select_cpu_vtime_enable,
+ .init = select_cpu_vtime_init,
+ .name = "select_cpu_vtime",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_vtime.c b/tools/testing/selftests/sched_ext/select_cpu_vtime.c
new file mode 100644
index 000000000000..b4629c2364f5
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_vtime.c
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_vtime.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_vtime *skel;
+
+ skel = select_cpu_vtime__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_vtime *skel = ctx;
+ struct bpf_link *link;
+
+ SCX_ASSERT(!skel->bss->consumed);
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_vtime_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_ASSERT(skel->bss->consumed);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_vtime *skel = ctx;
+
+ select_cpu_vtime__destroy(skel);
+}
+
+struct scx_test select_cpu_vtime = {
+ .name = "select_cpu_vtime",
+ .description = "Test doing direct vtime-dispatching from "
+ "ops.select_cpu(), to a non-built-in DSQ",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_vtime)
diff --git a/tools/testing/selftests/sched_ext/test_example.c b/tools/testing/selftests/sched_ext/test_example.c
new file mode 100644
index 000000000000..ce36cdf03cdc
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/test_example.c
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include "scx_test.h"
+
+static bool setup_called = false;
+static bool run_called = false;
+static bool cleanup_called = false;
+
+static int context = 10;
+
+static enum scx_test_status setup(void **ctx)
+{
+ setup_called = true;
+ *ctx = &context;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ int *arg = ctx;
+
+ SCX_ASSERT(setup_called);
+ SCX_ASSERT(!run_called && !cleanup_called);
+ SCX_EQ(*arg, context);
+
+ run_called = true;
+ return SCX_TEST_PASS;
+}
+
+static void cleanup (void *ctx)
+{
+ SCX_BUG_ON(!run_called || cleanup_called, "Wrong callbacks invoked");
+}
+
+struct scx_test example = {
+ .name = "example",
+ .description = "Validate the basic function of the test suite itself",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&example)
diff --git a/tools/testing/selftests/sched_ext/util.c b/tools/testing/selftests/sched_ext/util.c
new file mode 100644
index 000000000000..e47769c91918
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/util.c
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Returns read len on success, or -errno on failure. */
+static ssize_t read_text(const char *path, char *buf, size_t max_len)
+{
+ ssize_t len;
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -errno;
+
+ len = read(fd, buf, max_len - 1);
+
+ if (len >= 0)
+ buf[len] = 0;
+
+ close(fd);
+ return len < 0 ? -errno : len;
+}
+
+/* Returns written len on success, or -errno on failure. */
+static ssize_t write_text(const char *path, char *buf, ssize_t len)
+{
+ int fd;
+ ssize_t written;
+
+ fd = open(path, O_WRONLY | O_APPEND);
+ if (fd < 0)
+ return -errno;
+
+ written = write(fd, buf, len);
+ close(fd);
+ return written < 0 ? -errno : written;
+}
+
+long file_read_long(const char *path)
+{
+ char buf[128];
+
+
+ if (read_text(path, buf, sizeof(buf)) <= 0)
+ return -1;
+
+ return atol(buf);
+}
+
+int file_write_long(const char *path, long val)
+{
+ char buf[64];
+ int ret;
+
+ ret = sprintf(buf, "%lu", val);
+ if (ret < 0)
+ return ret;
+
+ if (write_text(path, buf, sizeof(buf)) <= 0)
+ return -1;
+
+ return 0;
+}
diff --git a/tools/testing/selftests/sched_ext/util.h b/tools/testing/selftests/sched_ext/util.h
new file mode 100644
index 000000000000..bc13dfec1267
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/util.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <void@manifault.com>
+ */
+
+#ifndef __SCX_TEST_UTIL_H__
+#define __SCX_TEST_UTIL_H__
+
+long file_read_long(const char *path);
+int file_write_long(const char *path, long val);
+
+#endif // __SCX_TEST_H__
--
2.45.2
Diff
---
tools/testing/selftests/sched_ext/.gitignore | 6 +
tools/testing/selftests/sched_ext/Makefile | 218 ++++++++++++++++++
tools/testing/selftests/sched_ext/config | 9 +
.../selftests/sched_ext/create_dsq.bpf.c | 58 +++++
.../testing/selftests/sched_ext/create_dsq.c | 57 +++++
.../sched_ext/ddsp_bogus_dsq_fail.bpf.c | 42 ++++
.../selftests/sched_ext/ddsp_bogus_dsq_fail.c | 57 +++++
.../sched_ext/ddsp_vtimelocal_fail.bpf.c | 39 ++++
.../sched_ext/ddsp_vtimelocal_fail.c | 56 +++++
.../selftests/sched_ext/dsp_local_on.bpf.c | 65 ++++++
.../selftests/sched_ext/dsp_local_on.c | 58 +++++
.../sched_ext/enq_last_no_enq_fails.bpf.c | 21 ++
.../sched_ext/enq_last_no_enq_fails.c | 60 +++++
.../sched_ext/enq_select_cpu_fails.bpf.c | 43 ++++
.../sched_ext/enq_select_cpu_fails.c | 61 +++++
tools/testing/selftests/sched_ext/exit.bpf.c | 84 +++++++
tools/testing/selftests/sched_ext/exit.c | 55 +++++
tools/testing/selftests/sched_ext/exit_test.h | 20 ++
.../testing/selftests/sched_ext/hotplug.bpf.c | 61 +++++
tools/testing/selftests/sched_ext/hotplug.c | 168 ++++++++++++++
.../selftests/sched_ext/hotplug_test.h | 15 ++
.../sched_ext/init_enable_count.bpf.c | 53 +++++
.../selftests/sched_ext/init_enable_count.c | 166 +++++++++++++
.../testing/selftests/sched_ext/maximal.bpf.c | 132 +++++++++++
tools/testing/selftests/sched_ext/maximal.c | 51 ++++
.../selftests/sched_ext/maybe_null.bpf.c | 36 +++
.../testing/selftests/sched_ext/maybe_null.c | 49 ++++
.../sched_ext/maybe_null_fail_dsp.bpf.c | 25 ++
.../sched_ext/maybe_null_fail_yld.bpf.c | 28 +++
.../testing/selftests/sched_ext/minimal.bpf.c | 21 ++
tools/testing/selftests/sched_ext/minimal.c | 58 +++++
.../selftests/sched_ext/prog_run.bpf.c | 32 +++
tools/testing/selftests/sched_ext/prog_run.c | 78 +++++++
.../testing/selftests/sched_ext/reload_loop.c | 75 ++++++
tools/testing/selftests/sched_ext/runner.c | 201 ++++++++++++++++
tools/testing/selftests/sched_ext/scx_test.h | 131 +++++++++++
.../selftests/sched_ext/select_cpu_dfl.bpf.c | 40 ++++
.../selftests/sched_ext/select_cpu_dfl.c | 72 ++++++
.../sched_ext/select_cpu_dfl_nodispatch.bpf.c | 89 +++++++
.../sched_ext/select_cpu_dfl_nodispatch.c | 72 ++++++
.../sched_ext/select_cpu_dispatch.bpf.c | 41 ++++
.../selftests/sched_ext/select_cpu_dispatch.c | 70 ++++++
.../select_cpu_dispatch_bad_dsq.bpf.c | 37 +++
.../sched_ext/select_cpu_dispatch_bad_dsq.c | 56 +++++
.../select_cpu_dispatch_dbl_dsp.bpf.c | 38 +++
.../sched_ext/select_cpu_dispatch_dbl_dsp.c | 56 +++++
.../sched_ext/select_cpu_vtime.bpf.c | 92 ++++++++
.../selftests/sched_ext/select_cpu_vtime.c | 59 +++++
.../selftests/sched_ext/test_example.c | 49 ++++
tools/testing/selftests/sched_ext/util.c | 71 ++++++
tools/testing/selftests/sched_ext/util.h | 13 ++
51 files changed, 3244 insertions(+)
create mode 100644 tools/testing/selftests/sched_ext/.gitignore
create mode 100644 tools/testing/selftests/sched_ext/Makefile
create mode 100644 tools/testing/selftests/sched_ext/config
create mode 100644 tools/testing/selftests/sched_ext/create_dsq.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/create_dsq.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
create mode 100644 tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/dsp_local_on.c
create mode 100644 tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
create mode 100644 tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
create mode 100644 tools/testing/selftests/sched_ext/exit.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/exit.c
create mode 100644 tools/testing/selftests/sched_ext/exit_test.h
create mode 100644 tools/testing/selftests/sched_ext/hotplug.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/hotplug.c
create mode 100644 tools/testing/selftests/sched_ext/hotplug_test.h
create mode 100644 tools/testing/selftests/sched_ext/init_enable_count.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/init_enable_count.c
create mode 100644 tools/testing/selftests/sched_ext/maximal.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maximal.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/minimal.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/minimal.c
create mode 100644 tools/testing/selftests/sched_ext/prog_run.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/prog_run.c
create mode 100644 tools/testing/selftests/sched_ext/reload_loop.c
create mode 100644 tools/testing/selftests/sched_ext/runner.c
create mode 100644 tools/testing/selftests/sched_ext/scx_test.h
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
create mode 100644 tools/testing/selftests/sched_ext/select_cpu_vtime.c
create mode 100644 tools/testing/selftests/sched_ext/test_example.c
create mode 100644 tools/testing/selftests/sched_ext/util.c
create mode 100644 tools/testing/selftests/sched_ext/util.h
diff --git a/tools/testing/selftests/sched_ext/.gitignore b/tools/testing/selftests/sched_ext/.gitignore
new file mode 100644
index 000000000000..ae5491a114c0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/.gitignore
@@ -0,0 +1,6 @@
+*
+!*.c
+!*.h
+!Makefile
+!.gitignore
+!config
diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile
new file mode 100644
index 000000000000..0754a2c110a1
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/Makefile
@@ -0,0 +1,218 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
+include ../../../build/Build.include
+include ../../../scripts/Makefile.arch
+include ../../../scripts/Makefile.include
+include ../lib.mk
+
+ifneq ($(LLVM),)
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+CC := $(LLVM_PREFIX)clang$(LLVM_SUFFIX) $(CLANG_FLAGS) -fintegrated-as
+else
+CC := gcc
+endif # LLVM
+
+ifneq ($(CROSS_COMPILE),)
+$(error CROSS_COMPILE not supported for scx selftests)
+endif # CROSS_COMPILE
+
+CURDIR := $(abspath .)
+REPOROOT := $(abspath ../../../..)
+TOOLSDIR := $(REPOROOT)/tools
+LIBDIR := $(TOOLSDIR)/lib
+BPFDIR := $(LIBDIR)/bpf
+TOOLSINCDIR := $(TOOLSDIR)/include
+BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool
+APIDIR := $(TOOLSINCDIR)/uapi
+GENDIR := $(REPOROOT)/include/generated
+GENHDR := $(GENDIR)/autoconf.h
+SCXTOOLSDIR := $(TOOLSDIR)/sched_ext
+SCXTOOLSINCDIR := $(TOOLSDIR)/sched_ext/include
+
+OUTPUT_DIR := $(CURDIR)/build
+OBJ_DIR := $(OUTPUT_DIR)/obj
+INCLUDE_DIR := $(OUTPUT_DIR)/include
+BPFOBJ_DIR := $(OBJ_DIR)/libbpf
+SCXOBJ_DIR := $(OBJ_DIR)/sched_ext
+BPFOBJ := $(BPFOBJ_DIR)/libbpf.a
+LIBBPF_OUTPUT := $(OBJ_DIR)/libbpf/libbpf.a
+DEFAULT_BPFTOOL := $(OUTPUT_DIR)/sbin/bpftool
+HOST_BUILD_DIR := $(OBJ_DIR)
+HOST_OUTPUT_DIR := $(OUTPUT_DIR)
+
+VMLINUX_BTF_PATHS ?= ../../../../vmlinux \
+ /sys/kernel/btf/vmlinux \
+ /boot/vmlinux-$(shell uname -r)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+ifeq ($(VMLINUX_BTF),)
+$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
+endif
+
+BPFTOOL ?= $(DEFAULT_BPFTOOL)
+
+ifneq ($(wildcard $(GENHDR)),)
+ GENFLAGS := -DHAVE_GENHDR
+endif
+
+CFLAGS += -g -O2 -rdynamic -pthread -Wall -Werror $(GENFLAGS) \
+ -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \
+ -I$(TOOLSINCDIR) -I$(APIDIR) -I$(CURDIR)/include -I$(SCXTOOLSINCDIR)
+
+# Silence some warnings when compiled with clang
+ifneq ($(LLVM),)
+CFLAGS += -Wno-unused-command-line-argument
+endif
+
+LDFLAGS = -lelf -lz -lpthread -lzstd
+
+IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
+ grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
+
+# Get Clang's default includes on this system, as opposed to those seen by
+# '-target bpf'. This fixes "missing" files on some architectures/distros,
+# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
+#
+# Use '-idirafter': Don't interfere with include mechanics except where the
+# build would have failed anyways.
+define get_sys_includes
+$(shell $(1) -v -E - </dev/null 2>&1 \
+ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
+$(shell $(1) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}')
+endef
+
+BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) \
+ $(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian) \
+ -I$(CURDIR)/include -I$(CURDIR)/include/bpf-compat \
+ -I$(INCLUDE_DIR) -I$(APIDIR) -I$(SCXTOOLSINCDIR) \
+ -I$(REPOROOT)/include \
+ $(call get_sys_includes,$(CLANG)) \
+ -Wall -Wno-compare-distinct-pointer-types \
+ -Wno-incompatible-function-pointer-types \
+ -O2 -mcpu=v3
+
+# sort removes libbpf duplicates when not cross-building
+MAKE_DIRS := $(sort $(OBJ_DIR)/libbpf $(OBJ_DIR)/libbpf \
+ $(OBJ_DIR)/bpftool $(OBJ_DIR)/resolve_btfids \
+ $(INCLUDE_DIR) $(SCXOBJ_DIR))
+
+$(MAKE_DIRS):
+ $(call msg,MKDIR,,$@)
+ $(Q)mkdir -p $@
+
+$(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
+ $(APIDIR)/linux/bpf.h \
+ | $(OBJ_DIR)/libbpf
+ $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
+ EXTRA_CFLAGS='-g -O0 -fPIC' \
+ DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
+
+$(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
+ $(LIBBPF_OUTPUT) | $(OBJ_DIR)/bpftool
+ $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
+ ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
+ EXTRA_CFLAGS='-g -O0' \
+ OUTPUT=$(OBJ_DIR)/bpftool/ \
+ LIBBPF_OUTPUT=$(OBJ_DIR)/libbpf/ \
+ LIBBPF_DESTDIR=$(OUTPUT_DIR)/ \
+ prefix= DESTDIR=$(OUTPUT_DIR)/ install-bin
+
+$(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
+ifeq ($(VMLINUX_H),)
+ $(call msg,GEN,,$@)
+ $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+else
+ $(call msg,CP,,$@)
+ $(Q)cp "$(VMLINUX_H)" $@
+endif
+
+$(SCXOBJ_DIR)/%.bpf.o: %.bpf.c $(INCLUDE_DIR)/vmlinux.h | $(BPFOBJ) $(SCXOBJ_DIR)
+ $(call msg,CLNG-BPF,,$(notdir $@))
+ $(Q)$(CLANG) $(BPF_CFLAGS) -target bpf -c $< -o $@
+
+$(INCLUDE_DIR)/%.bpf.skel.h: $(SCXOBJ_DIR)/%.bpf.o $(INCLUDE_DIR)/vmlinux.h $(BPFTOOL) | $(INCLUDE_DIR)
+ $(eval sched=$(notdir $@))
+ $(call msg,GEN-SKEL,,$(sched))
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked1.o) $<
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked2.o) $(<:.o=.linked1.o)
+ $(Q)$(BPFTOOL) gen object $(<:.o=.linked3.o) $(<:.o=.linked2.o)
+ $(Q)diff $(<:.o=.linked2.o) $(<:.o=.linked3.o)
+ $(Q)$(BPFTOOL) gen skeleton $(<:.o=.linked3.o) name $(subst .bpf.skel.h,,$(sched)) > $@
+ $(Q)$(BPFTOOL) gen subskeleton $(<:.o=.linked3.o) name $(subst .bpf.skel.h,,$(sched)) > $(@:.skel.h=.subskel.h)
+
+################
+# C schedulers #
+################
+
+override define CLEAN
+ rm -rf $(OUTPUT_DIR)
+ rm -f *.o *.bpf.o *.bpf.skel.h *.bpf.subskel.h
+ rm -f $(TEST_GEN_PROGS)
+ rm -f runner
+endef
+
+# Every testcase takes all of the BPF progs are dependencies by default. This
+# allows testcases to load any BPF scheduler, which is useful for testcases
+# that don't need their own prog to run their test.
+all_test_bpfprogs := $(foreach prog,$(wildcard *.bpf.c),$(INCLUDE_DIR)/$(patsubst %.c,%.skel.h,$(prog)))
+
+auto-test-targets := \
+ create_dsq \
+ enq_last_no_enq_fails \
+ enq_select_cpu_fails \
+ ddsp_bogus_dsq_fail \
+ ddsp_vtimelocal_fail \
+ dsp_local_on \
+ exit \
+ hotplug \
+ init_enable_count \
+ maximal \
+ maybe_null \
+ minimal \
+ prog_run \
+ reload_loop \
+ select_cpu_dfl \
+ select_cpu_dfl_nodispatch \
+ select_cpu_dispatch \
+ select_cpu_dispatch_bad_dsq \
+ select_cpu_dispatch_dbl_dsp \
+ select_cpu_vtime \
+ test_example \
+
+testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets)))
+
+$(SCXOBJ_DIR)/runner.o: runner.c | $(SCXOBJ_DIR)
+ $(CC) $(CFLAGS) -c $< -o $@
+
+# Create all of the test targets object files, whose testcase objects will be
+# registered into the runner in ELF constructors.
+#
+# Note that we must do double expansion here in order to support conditionally
+# compiling BPF object files only if one is present, as the wildcard Make
+# function doesn't support using implicit rules otherwise.
+$(testcase-targets): $(SCXOBJ_DIR)/%.o: %.c $(SCXOBJ_DIR)/runner.o $(all_test_bpfprogs) | $(SCXOBJ_DIR)
+ $(eval test=$(patsubst %.o,%.c,$(notdir $@)))
+ $(CC) $(CFLAGS) -c $< -o $@ $(SCXOBJ_DIR)/runner.o
+
+$(SCXOBJ_DIR)/util.o: util.c | $(SCXOBJ_DIR)
+ $(CC) $(CFLAGS) -c $< -o $@
+
+runner: $(SCXOBJ_DIR)/runner.o $(SCXOBJ_DIR)/util.o $(BPFOBJ) $(testcase-targets)
+ @echo "$(testcase-targets)"
+ $(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+TEST_GEN_PROGS := runner
+
+all: runner
+
+.PHONY: all clean help
+
+.DEFAULT_GOAL := all
+
+.DELETE_ON_ERROR:
+
+.SECONDARY:
diff --git a/tools/testing/selftests/sched_ext/config b/tools/testing/selftests/sched_ext/config
new file mode 100644
index 000000000000..0de9b4ee249d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/config
@@ -0,0 +1,9 @@
+CONFIG_SCHED_DEBUG=y
+CONFIG_SCHED_CLASS_EXT=y
+CONFIG_CGROUPS=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_EXT_GROUP_SCHED=y
+CONFIG_BPF=y
+CONFIG_BPF_SYSCALL=y
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_INFO_BTF=y
diff --git a/tools/testing/selftests/sched_ext/create_dsq.bpf.c b/tools/testing/selftests/sched_ext/create_dsq.bpf.c
new file mode 100644
index 000000000000..23f79ed343f0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/create_dsq.bpf.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Create and destroy DSQs in a loop.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+void BPF_STRUCT_OPS(create_dsq_exit_task, struct task_struct *p,
+ struct scx_exit_task_args *args)
+{
+ scx_bpf_destroy_dsq(p->pid);
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(create_dsq_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ s32 err;
+
+ err = scx_bpf_create_dsq(p->pid, -1);
+ if (err)
+ scx_bpf_error("Failed to create DSQ for %s[%d]",
+ p->comm, p->pid);
+
+ return err;
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(create_dsq_init)
+{
+ u32 i;
+ s32 err;
+
+ bpf_for(i, 0, 1024) {
+ err = scx_bpf_create_dsq(i, -1);
+ if (err) {
+ scx_bpf_error("Failed to create DSQ %d", i);
+ return 0;
+ }
+ }
+
+ bpf_for(i, 0, 1024) {
+ scx_bpf_destroy_dsq(i);
+ }
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops create_dsq_ops = {
+ .init_task = create_dsq_init_task,
+ .exit_task = create_dsq_exit_task,
+ .init = create_dsq_init,
+ .name = "create_dsq",
+};
diff --git a/tools/testing/selftests/sched_ext/create_dsq.c b/tools/testing/selftests/sched_ext/create_dsq.c
new file mode 100644
index 000000000000..fa946d9146d4
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/create_dsq.c
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "create_dsq.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct create_dsq *skel;
+
+ skel = create_dsq__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct create_dsq *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.create_dsq_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct create_dsq *skel = ctx;
+
+ create_dsq__destroy(skel);
+}
+
+struct scx_test create_dsq = {
+ .name = "create_dsq",
+ .description = "Create and destroy a dsq in a loop",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&create_dsq)
diff --git a/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
new file mode 100644
index 000000000000..e97ad41d354a
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+
+ if (cpu >= 0) {
+ /*
+ * If we dispatch to a bogus DSQ that will fall back to the
+ * builtin global DSQ, we fail gracefully.
+ */
+ scx_bpf_dispatch_vtime(p, 0xcafef00d, SCX_SLICE_DFL,
+ p->scx.dsq_vtime, 0);
+ return cpu;
+ }
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops ddsp_bogus_dsq_fail_ops = {
+ .select_cpu = ddsp_bogus_dsq_fail_select_cpu,
+ .exit = ddsp_bogus_dsq_fail_exit,
+ .name = "ddsp_bogus_dsq_fail",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
new file mode 100644
index 000000000000..e65d22f23f3b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.c
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "ddsp_bogus_dsq_fail.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel;
+
+ skel = ddsp_bogus_dsq_fail__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.ddsp_bogus_dsq_fail_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct ddsp_bogus_dsq_fail *skel = ctx;
+
+ ddsp_bogus_dsq_fail__destroy(skel);
+}
+
+struct scx_test ddsp_bogus_dsq_fail = {
+ .name = "ddsp_bogus_dsq_fail",
+ .description = "Verify we gracefully fail, and fall back to using a "
+ "built-in DSQ, if we do a direct dispatch to an invalid"
+ " DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&ddsp_bogus_dsq_fail)
diff --git a/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
new file mode 100644
index 000000000000..dde7e7dafbfb
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.bpf.c
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(ddsp_vtimelocal_fail_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+
+ if (cpu >= 0) {
+ /* Shouldn't be allowed to vtime dispatch to a builtin DSQ. */
+ scx_bpf_dispatch_vtime(p, SCX_DSQ_LOCAL, SCX_SLICE_DFL,
+ p->scx.dsq_vtime, 0);
+ return cpu;
+ }
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(ddsp_vtimelocal_fail_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops ddsp_vtimelocal_fail_ops = {
+ .select_cpu = ddsp_vtimelocal_fail_select_cpu,
+ .exit = ddsp_vtimelocal_fail_exit,
+ .name = "ddsp_vtimelocal_fail",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
new file mode 100644
index 000000000000..abafee587cd6
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/ddsp_vtimelocal_fail.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <unistd.h>
+#include "ddsp_vtimelocal_fail.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct ddsp_vtimelocal_fail *skel;
+
+ skel = ddsp_vtimelocal_fail__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct ddsp_vtimelocal_fail *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.ddsp_vtimelocal_fail_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct ddsp_vtimelocal_fail *skel = ctx;
+
+ ddsp_vtimelocal_fail__destroy(skel);
+}
+
+struct scx_test ddsp_vtimelocal_fail = {
+ .name = "ddsp_vtimelocal_fail",
+ .description = "Verify we gracefully fail, and fall back to using a "
+ "built-in DSQ, if we do a direct vtime dispatch to a "
+ "built-in DSQ from DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&ddsp_vtimelocal_fail)
diff --git a/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c b/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
new file mode 100644
index 000000000000..efb4672decb4
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/dsp_local_on.bpf.c
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+const volatile s32 nr_cpus;
+
+UEI_DEFINE(uei);
+
+struct {
+ __uint(type, BPF_MAP_TYPE_QUEUE);
+ __uint(max_entries, 8192);
+ __type(value, s32);
+} queue SEC(".maps");
+
+s32 BPF_STRUCT_OPS(dsp_local_on_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ s32 pid = p->pid;
+
+ if (bpf_map_push_elem(&queue, &pid, 0))
+ scx_bpf_error("Failed to enqueue %s[%d]", p->comm, p->pid);
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_dispatch, s32 cpu, struct task_struct *prev)
+{
+ s32 pid, target;
+ struct task_struct *p;
+
+ if (bpf_map_pop_elem(&queue, &pid))
+ return;
+
+ p = bpf_task_from_pid(pid);
+ if (!p)
+ return;
+
+ target = bpf_get_prandom_u32() % nr_cpus;
+
+ scx_bpf_dispatch(p, SCX_DSQ_LOCAL_ON | target, SCX_SLICE_DFL, 0);
+ bpf_task_release(p);
+}
+
+void BPF_STRUCT_OPS(dsp_local_on_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops dsp_local_on_ops = {
+ .select_cpu = dsp_local_on_select_cpu,
+ .enqueue = dsp_local_on_enqueue,
+ .dispatch = dsp_local_on_dispatch,
+ .exit = dsp_local_on_exit,
+ .name = "dsp_local_on",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/dsp_local_on.c b/tools/testing/selftests/sched_ext/dsp_local_on.c
new file mode 100644
index 000000000000..472851b56854
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/dsp_local_on.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <unistd.h>
+#include "dsp_local_on.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct dsp_local_on *skel;
+
+ skel = dsp_local_on__open();
+ SCX_FAIL_IF(!skel, "Failed to open");
+
+ skel->rodata->nr_cpus = libbpf_num_possible_cpus();
+ SCX_FAIL_IF(dsp_local_on__load(skel), "Failed to load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct dsp_local_on *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.dsp_local_on_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ /* Just sleeping is fine, plenty of scheduling events happening */
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct dsp_local_on *skel = ctx;
+
+ dsp_local_on__destroy(skel);
+}
+
+struct scx_test dsp_local_on = {
+ .name = "dsp_local_on",
+ .description = "Verify we can directly dispatch tasks to a local DSQs "
+ "from osp.dispatch()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&dsp_local_on)
diff --git a/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
new file mode 100644
index 000000000000..b0b99531d5d5
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.bpf.c
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+SEC(".struct_ops.link")
+struct sched_ext_ops enq_last_no_enq_fails_ops = {
+ .name = "enq_last_no_enq_fails",
+ /* Need to define ops.enqueue() with SCX_OPS_ENQ_LAST */
+ .flags = SCX_OPS_ENQ_LAST,
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
new file mode 100644
index 000000000000..2a3eda5e2c0b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_last_no_enq_fails.c
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "enq_last_no_enq_fails.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct enq_last_no_enq_fails *skel;
+
+ skel = enq_last_no_enq_fails__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct enq_last_no_enq_fails *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.enq_last_no_enq_fails_ops);
+ if (link) {
+ SCX_ERR("Incorrectly succeeded in to attaching scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct enq_last_no_enq_fails *skel = ctx;
+
+ enq_last_no_enq_fails__destroy(skel);
+}
+
+struct scx_test enq_last_no_enq_fails = {
+ .name = "enq_last_no_enq_fails",
+ .description = "Verify we fail to load a scheduler if we specify "
+ "the SCX_OPS_ENQ_LAST flag without defining "
+ "ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&enq_last_no_enq_fails)
diff --git a/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
new file mode 100644
index 000000000000..b3dfc1033cd6
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.bpf.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+/* Manually specify the signature until the kfunc is added to the scx repo. */
+s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
+ bool *found) __ksym;
+
+s32 BPF_STRUCT_OPS(enq_select_cpu_fails_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(enq_select_cpu_fails_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ /*
+ * Need to initialize the variable or the verifier will fail to load.
+ * Improving these semantics is actively being worked on.
+ */
+ bool found = false;
+
+ /* Can only call from ops.select_cpu() */
+ scx_bpf_select_cpu_dfl(p, 0, 0, &found);
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops enq_select_cpu_fails_ops = {
+ .select_cpu = enq_select_cpu_fails_select_cpu,
+ .enqueue = enq_select_cpu_fails_enqueue,
+ .name = "enq_select_cpu_fails",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
new file mode 100644
index 000000000000..dd1350e5f002
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/enq_select_cpu_fails.c
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "enq_select_cpu_fails.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct enq_select_cpu_fails *skel;
+
+ skel = enq_select_cpu_fails__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct enq_select_cpu_fails *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.enq_select_cpu_fails_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ sleep(1);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct enq_select_cpu_fails *skel = ctx;
+
+ enq_select_cpu_fails__destroy(skel);
+}
+
+struct scx_test enq_select_cpu_fails = {
+ .name = "enq_select_cpu_fails",
+ .description = "Verify we fail to call scx_bpf_select_cpu_dfl() "
+ "from ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&enq_select_cpu_fails)
diff --git a/tools/testing/selftests/sched_ext/exit.bpf.c b/tools/testing/selftests/sched_ext/exit.bpf.c
new file mode 100644
index 000000000000..ae12ddaac921
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit.bpf.c
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+#include "exit_test.h"
+
+const volatile int exit_point;
+UEI_DEFINE(uei);
+
+#define EXIT_CLEANLY() scx_bpf_exit(exit_point, "%d", exit_point)
+
+s32 BPF_STRUCT_OPS(exit_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ bool found;
+
+ if (exit_point == EXIT_SELECT_CPU)
+ EXIT_CLEANLY();
+
+ return scx_bpf_select_cpu_dfl(p, prev_cpu, wake_flags, &found);
+}
+
+void BPF_STRUCT_OPS(exit_enqueue, struct task_struct *p, u64 enq_flags)
+{
+ if (exit_point == EXIT_ENQUEUE)
+ EXIT_CLEANLY();
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+void BPF_STRUCT_OPS(exit_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (exit_point == EXIT_DISPATCH)
+ EXIT_CLEANLY();
+
+ scx_bpf_consume(SCX_DSQ_GLOBAL);
+}
+
+void BPF_STRUCT_OPS(exit_enable, struct task_struct *p)
+{
+ if (exit_point == EXIT_ENABLE)
+ EXIT_CLEANLY();
+}
+
+s32 BPF_STRUCT_OPS(exit_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ if (exit_point == EXIT_INIT_TASK)
+ EXIT_CLEANLY();
+
+ return 0;
+}
+
+void BPF_STRUCT_OPS(exit_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(exit_init)
+{
+ if (exit_point == EXIT_INIT)
+ EXIT_CLEANLY();
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops exit_ops = {
+ .select_cpu = exit_select_cpu,
+ .enqueue = exit_enqueue,
+ .dispatch = exit_dispatch,
+ .init_task = exit_init_task,
+ .enable = exit_enable,
+ .exit = exit_exit,
+ .init = exit_init,
+ .name = "exit",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/exit.c b/tools/testing/selftests/sched_ext/exit.c
new file mode 100644
index 000000000000..31bcd06e21cd
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit.c
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "exit.bpf.skel.h"
+#include "scx_test.h"
+
+#include "exit_test.h"
+
+static enum scx_test_status run(void *ctx)
+{
+ enum exit_test_case tc;
+
+ for (tc = 0; tc < NUM_EXITS; tc++) {
+ struct exit *skel;
+ struct bpf_link *link;
+ char buf[16];
+
+ skel = exit__open();
+ skel->rodata->exit_point = tc;
+ exit__load(skel);
+ link = bpf_map__attach_struct_ops(skel->maps.exit_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ exit__destroy(skel);
+ return SCX_TEST_FAIL;
+ }
+
+ /* Assumes uei.kind is written last */
+ while (skel->data->uei.kind == EXIT_KIND(SCX_EXIT_NONE))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG_BPF));
+ SCX_EQ(skel->data->uei.exit_code, tc);
+ sprintf(buf, "%d", tc);
+ SCX_ASSERT(!strcmp(skel->data->uei.msg, buf));
+ bpf_link__destroy(link);
+ exit__destroy(skel);
+ }
+
+ return SCX_TEST_PASS;
+}
+
+struct scx_test exit_test = {
+ .name = "exit",
+ .description = "Verify we can cleanly exit a scheduler in multiple places",
+ .run = run,
+};
+REGISTER_SCX_TEST(&exit_test)
diff --git a/tools/testing/selftests/sched_ext/exit_test.h b/tools/testing/selftests/sched_ext/exit_test.h
new file mode 100644
index 000000000000..94f0268b9cb8
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/exit_test.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __EXIT_TEST_H__
+#define __EXIT_TEST_H__
+
+enum exit_test_case {
+ EXIT_SELECT_CPU,
+ EXIT_ENQUEUE,
+ EXIT_DISPATCH,
+ EXIT_ENABLE,
+ EXIT_INIT_TASK,
+ EXIT_INIT,
+ NUM_EXITS,
+};
+
+#endif // # __EXIT_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/hotplug.bpf.c b/tools/testing/selftests/sched_ext/hotplug.bpf.c
new file mode 100644
index 000000000000..8f2601db39f3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug.bpf.c
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+#include "hotplug_test.h"
+
+UEI_DEFINE(uei);
+
+void BPF_STRUCT_OPS(hotplug_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+static void exit_from_hotplug(s32 cpu, bool onlining)
+{
+ /*
+ * Ignored, just used to verify that we can invoke blocking kfuncs
+ * from the hotplug path.
+ */
+ scx_bpf_create_dsq(0, -1);
+
+ s64 code = SCX_ECODE_ACT_RESTART | HOTPLUG_EXIT_RSN;
+
+ if (onlining)
+ code |= HOTPLUG_ONLINING;
+
+ scx_bpf_exit(code, "hotplug event detected (%d going %s)", cpu,
+ onlining ? "online" : "offline");
+}
+
+void BPF_STRUCT_OPS_SLEEPABLE(hotplug_cpu_online, s32 cpu)
+{
+ exit_from_hotplug(cpu, true);
+}
+
+void BPF_STRUCT_OPS_SLEEPABLE(hotplug_cpu_offline, s32 cpu)
+{
+ exit_from_hotplug(cpu, false);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops hotplug_cb_ops = {
+ .cpu_online = hotplug_cpu_online,
+ .cpu_offline = hotplug_cpu_offline,
+ .exit = hotplug_exit,
+ .name = "hotplug_cbs",
+ .timeout_ms = 1000U,
+};
+
+SEC(".struct_ops.link")
+struct sched_ext_ops hotplug_nocb_ops = {
+ .exit = hotplug_exit,
+ .name = "hotplug_nocbs",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/hotplug.c b/tools/testing/selftests/sched_ext/hotplug.c
new file mode 100644
index 000000000000..87bf220b1bce
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug.c
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sched.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "hotplug_test.h"
+#include "hotplug.bpf.skel.h"
+#include "scx_test.h"
+#include "util.h"
+
+const char *online_path = "/sys/devices/system/cpu/cpu1/online";
+
+static bool is_cpu_online(void)
+{
+ return file_read_long(online_path) > 0;
+}
+
+static void toggle_online_status(bool online)
+{
+ long val = online ? 1 : 0;
+ int ret;
+
+ ret = file_write_long(online_path, val);
+ if (ret != 0)
+ fprintf(stderr, "Failed to bring CPU %s (%s)",
+ online ? "online" : "offline", strerror(errno));
+}
+
+static enum scx_test_status setup(void **ctx)
+{
+ if (!is_cpu_online())
+ return SCX_TEST_SKIP;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status test_hotplug(bool onlining, bool cbs_defined)
+{
+ struct hotplug *skel;
+ struct bpf_link *link;
+ long kind, code;
+
+ SCX_ASSERT(is_cpu_online());
+
+ skel = hotplug__open_and_load();
+ SCX_ASSERT(skel);
+
+ /* Testing the offline -> online path, so go offline before starting */
+ if (onlining)
+ toggle_online_status(0);
+
+ if (cbs_defined) {
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_BPF);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) | HOTPLUG_EXIT_RSN;
+ if (onlining)
+ code |= HOTPLUG_ONLINING;
+ } else {
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
+ SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
+ }
+
+ if (cbs_defined)
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_cb_ops);
+ else
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
+
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ hotplug__destroy(skel);
+ return SCX_TEST_FAIL;
+ }
+
+ toggle_online_status(onlining ? 1 : 0);
+
+ while (!UEI_EXITED(skel, uei))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, kind);
+ SCX_EQ(UEI_REPORT(skel, uei), code);
+
+ if (!onlining)
+ toggle_online_status(1);
+
+ bpf_link__destroy(link);
+ hotplug__destroy(skel);
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status test_hotplug_attach(void)
+{
+ struct hotplug *skel;
+ struct bpf_link *link;
+ enum scx_test_status status = SCX_TEST_PASS;
+ long kind, code;
+
+ SCX_ASSERT(is_cpu_online());
+ SCX_ASSERT(scx_hotplug_seq() > 0);
+
+ skel = SCX_OPS_OPEN(hotplug_nocb_ops, hotplug);
+ SCX_ASSERT(skel);
+
+ SCX_OPS_LOAD(skel, hotplug_nocb_ops, hotplug, uei);
+
+ /*
+ * Take the CPU offline to increment the global hotplug seq, which
+ * should cause attach to fail due to us setting the hotplug seq above
+ */
+ toggle_online_status(0);
+ link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
+
+ toggle_online_status(1);
+
+ SCX_ASSERT(link);
+ while (!UEI_EXITED(skel, uei))
+ sched_yield();
+
+ kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
+ code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
+ SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
+ SCX_EQ(skel->data->uei.kind, kind);
+ SCX_EQ(UEI_REPORT(skel, uei), code);
+
+ bpf_link__destroy(link);
+ hotplug__destroy(skel);
+
+ return status;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+
+#define HP_TEST(__onlining, __cbs_defined) ({ \
+ if (test_hotplug(__onlining, __cbs_defined) != SCX_TEST_PASS) \
+ return SCX_TEST_FAIL; \
+})
+
+ HP_TEST(true, true);
+ HP_TEST(false, true);
+ HP_TEST(true, false);
+ HP_TEST(false, false);
+
+#undef HP_TEST
+
+ return test_hotplug_attach();
+}
+
+static void cleanup(void *ctx)
+{
+ toggle_online_status(1);
+}
+
+struct scx_test hotplug_test = {
+ .name = "hotplug",
+ .description = "Verify hotplug behavior",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&hotplug_test)
diff --git a/tools/testing/selftests/sched_ext/hotplug_test.h b/tools/testing/selftests/sched_ext/hotplug_test.h
new file mode 100644
index 000000000000..73d236f90787
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug_test.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __HOTPLUG_TEST_H__
+#define __HOTPLUG_TEST_H__
+
+enum hotplug_test_flags {
+ HOTPLUG_EXIT_RSN = 1LLU << 0,
+ HOTPLUG_ONLINING = 1LLU << 1,
+};
+
+#endif // # __HOTPLUG_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/init_enable_count.bpf.c b/tools/testing/selftests/sched_ext/init_enable_count.bpf.c
new file mode 100644
index 000000000000..47ea89a626c3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/init_enable_count.bpf.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that verifies that we do proper counting of init, enable, etc
+ * callbacks.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 init_task_cnt, exit_task_cnt, enable_cnt, disable_cnt;
+u64 init_fork_cnt, init_transition_cnt;
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(cnt_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ __sync_fetch_and_add(&init_task_cnt, 1);
+
+ if (args->fork)
+ __sync_fetch_and_add(&init_fork_cnt, 1);
+ else
+ __sync_fetch_and_add(&init_transition_cnt, 1);
+
+ return 0;
+}
+
+void BPF_STRUCT_OPS(cnt_exit_task, struct task_struct *p)
+{
+ __sync_fetch_and_add(&exit_task_cnt, 1);
+}
+
+void BPF_STRUCT_OPS(cnt_enable, struct task_struct *p)
+{
+ __sync_fetch_and_add(&enable_cnt, 1);
+}
+
+void BPF_STRUCT_OPS(cnt_disable, struct task_struct *p)
+{
+ __sync_fetch_and_add(&disable_cnt, 1);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops init_enable_count_ops = {
+ .init_task = cnt_init_task,
+ .exit_task = cnt_exit_task,
+ .enable = cnt_enable,
+ .disable = cnt_disable,
+ .name = "init_enable_count",
+};
diff --git a/tools/testing/selftests/sched_ext/init_enable_count.c b/tools/testing/selftests/sched_ext/init_enable_count.c
new file mode 100644
index 000000000000..97d45f1e5597
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/init_enable_count.c
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <sched.h>
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include "scx_test.h"
+#include "init_enable_count.bpf.skel.h"
+
+#define SCHED_EXT 7
+
+static struct init_enable_count *
+open_load_prog(bool global)
+{
+ struct init_enable_count *skel;
+
+ skel = init_enable_count__open();
+ SCX_BUG_ON(!skel, "Failed to open skel");
+
+ if (!global)
+ skel->struct_ops.init_enable_count_ops->flags |= SCX_OPS_SWITCH_PARTIAL;
+
+ SCX_BUG_ON(init_enable_count__load(skel), "Failed to load skel");
+
+ return skel;
+}
+
+static enum scx_test_status run_test(bool global)
+{
+ struct init_enable_count *skel;
+ struct bpf_link *link;
+ const u32 num_children = 5, num_pre_forks = 1024;
+ int ret, i, status;
+ struct sched_param param = {};
+ pid_t pids[num_pre_forks];
+
+ skel = open_load_prog(global);
+
+ /*
+ * Fork a bunch of children before we attach the scheduler so that we
+ * ensure (at least in practical terms) that there are more tasks that
+ * transition from SCHED_OTHER -> SCHED_EXT than there are tasks that
+ * take the fork() path either below or in other processes.
+ */
+ for (i = 0; i < num_pre_forks; i++) {
+ pids[i] = fork();
+ SCX_FAIL_IF(pids[i] < 0, "Failed to fork child");
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ link = bpf_map__attach_struct_ops(skel->maps.init_enable_count_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ for (i = 0; i < num_pre_forks; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for pre-forked child\n");
+
+ SCX_FAIL_IF(status != 0, "Pre-forked child %d exited with status %d\n", i,
+ status);
+ }
+
+ bpf_link__destroy(link);
+ SCX_GE(skel->bss->init_task_cnt, num_pre_forks);
+ SCX_GE(skel->bss->exit_task_cnt, num_pre_forks);
+
+ link = bpf_map__attach_struct_ops(skel->maps.init_enable_count_ops);
+ SCX_FAIL_IF(!link, "Failed to attach struct_ops");
+
+ /* SCHED_EXT children */
+ for (i = 0; i < num_children; i++) {
+ pids[i] = fork();
+ SCX_FAIL_IF(pids[i] < 0, "Failed to fork child");
+
+ if (pids[i] == 0) {
+ ret = sched_setscheduler(0, SCHED_EXT, ¶m);
+ SCX_BUG_ON(ret, "Failed to set sched to sched_ext");
+
+ /*
+ * Reset to SCHED_OTHER for half of them. Counts for
+ * everything should still be the same regardless, as
+ * ops.disable() is invoked even if a task is still on
+ * SCHED_EXT before it exits.
+ */
+ if (i % 2 == 0) {
+ ret = sched_setscheduler(0, SCHED_OTHER, ¶m);
+ SCX_BUG_ON(ret, "Failed to reset sched to normal");
+ }
+ exit(0);
+ }
+ }
+ for (i = 0; i < num_children; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for sched_ext child\n");
+
+ SCX_FAIL_IF(status != 0, "sched_ext child %d exited with status %d\n", i,
+ status);
+ }
+
+ /* SCHED_OTHER children */
+ for (i = 0; i < num_children; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0)
+ exit(0);
+ }
+
+ for (i = 0; i < num_children; i++) {
+ SCX_FAIL_IF(waitpid(pids[i], &status, 0) != pids[i],
+ "Failed to wait for normal child\n");
+
+ SCX_FAIL_IF(status != 0, "Normal child %d exited with status %d\n", i,
+ status);
+ }
+
+ bpf_link__destroy(link);
+
+ SCX_GE(skel->bss->init_task_cnt, 2 * num_children);
+ SCX_GE(skel->bss->exit_task_cnt, 2 * num_children);
+
+ if (global) {
+ SCX_GE(skel->bss->enable_cnt, 2 * num_children);
+ SCX_GE(skel->bss->disable_cnt, 2 * num_children);
+ } else {
+ SCX_EQ(skel->bss->enable_cnt, num_children);
+ SCX_EQ(skel->bss->disable_cnt, num_children);
+ }
+ /*
+ * We forked a ton of tasks before we attached the scheduler above, so
+ * this should be fine. Technically it could be flaky if a ton of forks
+ * are happening at the same time in other processes, but that should
+ * be exceedingly unlikely.
+ */
+ SCX_GT(skel->bss->init_transition_cnt, skel->bss->init_fork_cnt);
+ SCX_GE(skel->bss->init_fork_cnt, 2 * num_children);
+
+ init_enable_count__destroy(skel);
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ enum scx_test_status status;
+
+ status = run_test(true);
+ if (status != SCX_TEST_PASS)
+ return status;
+
+ return run_test(false);
+}
+
+struct scx_test init_enable_count = {
+ .name = "init_enable_count",
+ .description = "Verify we do the correct amount of counting of init, "
+ "enable, etc callbacks.",
+ .run = run,
+};
+REGISTER_SCX_TEST(&init_enable_count)
diff --git a/tools/testing/selftests/sched_ext/maximal.bpf.c b/tools/testing/selftests/sched_ext/maximal.bpf.c
new file mode 100644
index 000000000000..44612fdaf399
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maximal.bpf.c
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler with every callback defined.
+ *
+ * This scheduler defines every callback.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+s32 BPF_STRUCT_OPS(maximal_select_cpu, struct task_struct *p, s32 prev_cpu,
+ u64 wake_flags)
+{
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(maximal_enqueue, struct task_struct *p, u64 enq_flags)
+{
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+void BPF_STRUCT_OPS(maximal_dequeue, struct task_struct *p, u64 deq_flags)
+{}
+
+void BPF_STRUCT_OPS(maximal_dispatch, s32 cpu, struct task_struct *prev)
+{
+ scx_bpf_consume(SCX_DSQ_GLOBAL);
+}
+
+void BPF_STRUCT_OPS(maximal_runnable, struct task_struct *p, u64 enq_flags)
+{}
+
+void BPF_STRUCT_OPS(maximal_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maximal_stopping, struct task_struct *p, bool runnable)
+{}
+
+void BPF_STRUCT_OPS(maximal_quiescent, struct task_struct *p, u64 deq_flags)
+{}
+
+bool BPF_STRUCT_OPS(maximal_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ return false;
+}
+
+bool BPF_STRUCT_OPS(maximal_core_sched_before, struct task_struct *a,
+ struct task_struct *b)
+{
+ return false;
+}
+
+void BPF_STRUCT_OPS(maximal_set_weight, struct task_struct *p, u32 weight)
+{}
+
+void BPF_STRUCT_OPS(maximal_set_cpumask, struct task_struct *p,
+ const struct cpumask *cpumask)
+{}
+
+void BPF_STRUCT_OPS(maximal_update_idle, s32 cpu, bool idle)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_acquire, s32 cpu,
+ struct scx_cpu_acquire_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_release, s32 cpu,
+ struct scx_cpu_release_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_online, s32 cpu)
+{}
+
+void BPF_STRUCT_OPS(maximal_cpu_offline, s32 cpu)
+{}
+
+s32 BPF_STRUCT_OPS(maximal_init_task, struct task_struct *p,
+ struct scx_init_task_args *args)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_enable, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maximal_exit_task, struct task_struct *p,
+ struct scx_exit_task_args *args)
+{}
+
+void BPF_STRUCT_OPS(maximal_disable, struct task_struct *p)
+{}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(maximal_init)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_exit, struct scx_exit_info *info)
+{}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maximal_ops = {
+ .select_cpu = maximal_select_cpu,
+ .enqueue = maximal_enqueue,
+ .dequeue = maximal_dequeue,
+ .dispatch = maximal_dispatch,
+ .runnable = maximal_runnable,
+ .running = maximal_running,
+ .stopping = maximal_stopping,
+ .quiescent = maximal_quiescent,
+ .yield = maximal_yield,
+ .core_sched_before = maximal_core_sched_before,
+ .set_weight = maximal_set_weight,
+ .set_cpumask = maximal_set_cpumask,
+ .update_idle = maximal_update_idle,
+ .cpu_acquire = maximal_cpu_acquire,
+ .cpu_release = maximal_cpu_release,
+ .cpu_online = maximal_cpu_online,
+ .cpu_offline = maximal_cpu_offline,
+ .init_task = maximal_init_task,
+ .enable = maximal_enable,
+ .exit_task = maximal_exit_task,
+ .disable = maximal_disable,
+ .init = maximal_init,
+ .exit = maximal_exit,
+ .name = "maximal",
+};
diff --git a/tools/testing/selftests/sched_ext/maximal.c b/tools/testing/selftests/sched_ext/maximal.c
new file mode 100644
index 000000000000..f38fc973c380
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maximal.c
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maximal.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct maximal *skel;
+
+ skel = maximal__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct maximal *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.maximal_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct maximal *skel = ctx;
+
+ maximal__destroy(skel);
+}
+
+struct scx_test maximal = {
+ .name = "maximal",
+ .description = "Verify we can load a scheduler with every callback defined",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&maximal)
diff --git a/tools/testing/selftests/sched_ext/maybe_null.bpf.c b/tools/testing/selftests/sched_ext/maybe_null.bpf.c
new file mode 100644
index 000000000000..27d0f386acfb
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.bpf.c
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maybe_null_success_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (p != NULL)
+ vtime_test = p->scx.dsq_vtime;
+}
+
+bool BPF_STRUCT_OPS(maybe_null_success_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ if (to)
+ bpf_printk("Yielding to %s[%d]", to->comm, to->pid);
+
+ return false;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_success = {
+ .dispatch = maybe_null_success_dispatch,
+ .yield = maybe_null_success_yield,
+ .enable = maybe_null_running,
+ .name = "minimal",
+};
diff --git a/tools/testing/selftests/sched_ext/maybe_null.c b/tools/testing/selftests/sched_ext/maybe_null.c
new file mode 100644
index 000000000000..31cfafb0cf65
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.c
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maybe_null.bpf.skel.h"
+#include "maybe_null_fail_dsp.bpf.skel.h"
+#include "maybe_null_fail_yld.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status run(void *ctx)
+{
+ struct maybe_null *skel;
+ struct maybe_null_fail_dsp *fail_dsp;
+ struct maybe_null_fail_yld *fail_yld;
+
+ skel = maybe_null__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load maybe_null skel");
+ return SCX_TEST_FAIL;
+ }
+ maybe_null__destroy(skel);
+
+ fail_dsp = maybe_null_fail_dsp__open_and_load();
+ if (fail_dsp) {
+ maybe_null_fail_dsp__destroy(fail_dsp);
+ SCX_ERR("Should failed to open and load maybe_null_fail_dsp skel");
+ return SCX_TEST_FAIL;
+ }
+
+ fail_yld = maybe_null_fail_yld__open_and_load();
+ if (fail_yld) {
+ maybe_null_fail_yld__destroy(fail_yld);
+ SCX_ERR("Should failed to open and load maybe_null_fail_yld skel");
+ return SCX_TEST_FAIL;
+ }
+
+ return SCX_TEST_PASS;
+}
+
+struct scx_test maybe_null = {
+ .name = "maybe_null",
+ .description = "Verify if PTR_MAYBE_NULL work for .dispatch",
+ .run = run,
+};
+REGISTER_SCX_TEST(&maybe_null)
diff --git a/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c b/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
new file mode 100644
index 000000000000..c0641050271d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null_fail_dsp.bpf.c
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+void BPF_STRUCT_OPS(maybe_null_fail_dispatch, s32 cpu, struct task_struct *p)
+{
+ vtime_test = p->scx.dsq_vtime;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_fail = {
+ .dispatch = maybe_null_fail_dispatch,
+ .enable = maybe_null_running,
+ .name = "maybe_null_fail_dispatch",
+};
diff --git a/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c b/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
new file mode 100644
index 000000000000..3c1740028e3b
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null_fail_yld.bpf.c
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+u64 vtime_test;
+
+void BPF_STRUCT_OPS(maybe_null_running, struct task_struct *p)
+{}
+
+bool BPF_STRUCT_OPS(maybe_null_fail_yield, struct task_struct *from,
+ struct task_struct *to)
+{
+ bpf_printk("Yielding to %s[%d]", to->comm, to->pid);
+
+ return false;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_fail = {
+ .yield = maybe_null_fail_yield,
+ .enable = maybe_null_running,
+ .name = "maybe_null_fail_yield",
+};
diff --git a/tools/testing/selftests/sched_ext/minimal.bpf.c b/tools/testing/selftests/sched_ext/minimal.bpf.c
new file mode 100644
index 000000000000..6a7eccef0104
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/minimal.bpf.c
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A completely minimal scheduler.
+ *
+ * This scheduler defines the absolute minimal set of struct sched_ext_ops
+ * fields: its name. It should _not_ fail to be loaded, and can be used to
+ * exercise the default scheduling paths in ext.c.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+SEC(".struct_ops.link")
+struct sched_ext_ops minimal_ops = {
+ .name = "minimal",
+};
diff --git a/tools/testing/selftests/sched_ext/minimal.c b/tools/testing/selftests/sched_ext/minimal.c
new file mode 100644
index 000000000000..6c5db8ebbf8a
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/minimal.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "minimal.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct minimal *skel;
+
+ skel = minimal__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct minimal *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.minimal_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ return SCX_TEST_FAIL;
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct minimal *skel = ctx;
+
+ minimal__destroy(skel);
+}
+
+struct scx_test minimal = {
+ .name = "minimal",
+ .description = "Verify we can load a fully minimal scheduler",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&minimal)
diff --git a/tools/testing/selftests/sched_ext/prog_run.bpf.c b/tools/testing/selftests/sched_ext/prog_run.bpf.c
new file mode 100644
index 000000000000..fd2c8f12af16
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/prog_run.bpf.c
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates that we can invoke sched_ext kfuncs in
+ * BPF_PROG_TYPE_SYSCALL programs.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+
+#include <scx/common.bpf.h>
+
+UEI_DEFINE(uei);
+
+char _license[] SEC("license") = "GPL";
+
+SEC("syscall")
+int BPF_PROG(prog_run_syscall)
+{
+ scx_bpf_exit(0xdeadbeef, "Exited from PROG_RUN");
+ return 0;
+}
+
+void BPF_STRUCT_OPS(prog_run_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops prog_run_ops = {
+ .exit = prog_run_exit,
+ .name = "prog_run",
+};
diff --git a/tools/testing/selftests/sched_ext/prog_run.c b/tools/testing/selftests/sched_ext/prog_run.c
new file mode 100644
index 000000000000..3cd57ef8daaa
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/prog_run.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <sched.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "prog_run.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct prog_run *skel;
+
+ skel = prog_run__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct prog_run *skel = ctx;
+ struct bpf_link *link;
+ int prog_fd, err = 0;
+
+ prog_fd = bpf_program__fd(skel->progs.prog_run_syscall);
+ if (prog_fd < 0) {
+ SCX_ERR("Failed to get BPF_PROG_RUN prog");
+ return SCX_TEST_FAIL;
+ }
+
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+ link = bpf_map__attach_struct_ops(skel->maps.prog_run_ops);
+ if (!link) {
+ SCX_ERR("Failed to attach scheduler");
+ close(prog_fd);
+ return SCX_TEST_FAIL;
+ }
+
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ SCX_EQ(err, 0);
+
+ /* Assumes uei.kind is written last */
+ while (skel->data->uei.kind == EXIT_KIND(SCX_EXIT_NONE))
+ sched_yield();
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG_BPF));
+ SCX_EQ(skel->data->uei.exit_code, 0xdeadbeef);
+ close(prog_fd);
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct prog_run *skel = ctx;
+
+ prog_run__destroy(skel);
+}
+
+struct scx_test prog_run = {
+ .name = "prog_run",
+ .description = "Verify we can call into a scheduler with BPF_PROG_RUN, and invoke kfuncs",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&prog_run)
diff --git a/tools/testing/selftests/sched_ext/reload_loop.c b/tools/testing/selftests/sched_ext/reload_loop.c
new file mode 100644
index 000000000000..5cfba2d6e056
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/reload_loop.c
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <pthread.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "maximal.bpf.skel.h"
+#include "scx_test.h"
+
+static struct maximal *skel;
+static pthread_t threads[2];
+
+bool force_exit = false;
+
+static enum scx_test_status setup(void **ctx)
+{
+ skel = maximal__open_and_load();
+ if (!skel) {
+ SCX_ERR("Failed to open and load skel");
+ return SCX_TEST_FAIL;
+ }
+
+ return SCX_TEST_PASS;
+}
+
+static void *do_reload_loop(void *arg)
+{
+ u32 i;
+
+ for (i = 0; i < 1024 && !force_exit; i++) {
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.maximal_ops);
+ if (link)
+ bpf_link__destroy(link);
+ }
+
+ return NULL;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ int err;
+ void *ret;
+
+ err = pthread_create(&threads[0], NULL, do_reload_loop, NULL);
+ SCX_FAIL_IF(err, "Failed to create thread 0");
+
+ err = pthread_create(&threads[1], NULL, do_reload_loop, NULL);
+ SCX_FAIL_IF(err, "Failed to create thread 1");
+
+ SCX_FAIL_IF(pthread_join(threads[0], &ret), "thread 0 failed");
+ SCX_FAIL_IF(pthread_join(threads[1], &ret), "thread 1 failed");
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ force_exit = true;
+ maximal__destroy(skel);
+}
+
+struct scx_test reload_loop = {
+ .name = "reload_loop",
+ .description = "Stress test loading and unloading schedulers repeatedly in a tight loop",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&reload_loop)
diff --git a/tools/testing/selftests/sched_ext/runner.c b/tools/testing/selftests/sched_ext/runner.c
new file mode 100644
index 000000000000..eab48c7ff309
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/runner.c
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <libgen.h>
+#include <bpf/bpf.h>
+#include "scx_test.h"
+
+const char help_fmt[] =
+"The runner for sched_ext tests.\n"
+"\n"
+"The runner is statically linked against all testcases, and runs them all serially.\n"
+"It's required for the testcases to be serial, as only a single host-wide sched_ext\n"
+"scheduler may be loaded at any given time."
+"\n"
+"Usage: %s [-t TEST] [-h]\n"
+"\n"
+" -t TEST Only run tests whose name includes this string\n"
+" -s Include print output for skipped tests\n"
+" -q Don't print the test descriptions during run\n"
+" -h Display this help and exit\n";
+
+static volatile int exit_req;
+static bool quiet, print_skipped;
+
+#define MAX_SCX_TESTS 2048
+
+static struct scx_test __scx_tests[MAX_SCX_TESTS];
+static unsigned __scx_num_tests = 0;
+
+static void sigint_handler(int simple)
+{
+ exit_req = 1;
+}
+
+static void print_test_preamble(const struct scx_test *test, bool quiet)
+{
+ printf("===== START =====\n");
+ printf("TEST: %s\n", test->name);
+ if (!quiet)
+ printf("DESCRIPTION: %s\n", test->description);
+ printf("OUTPUT:\n");
+}
+
+static const char *status_to_result(enum scx_test_status status)
+{
+ switch (status) {
+ case SCX_TEST_PASS:
+ case SCX_TEST_SKIP:
+ return "ok";
+ case SCX_TEST_FAIL:
+ return "not ok";
+ default:
+ return "<UNKNOWN>";
+ }
+}
+
+static void print_test_result(const struct scx_test *test,
+ enum scx_test_status status,
+ unsigned int testnum)
+{
+ const char *result = status_to_result(status);
+ const char *directive = status == SCX_TEST_SKIP ? "SKIP " : "";
+
+ printf("%s %u %s # %s\n", result, testnum, test->name, directive);
+ printf("===== END =====\n");
+}
+
+static bool should_skip_test(const struct scx_test *test, const char * filter)
+{
+ return !strstr(test->name, filter);
+}
+
+static enum scx_test_status run_test(const struct scx_test *test)
+{
+ enum scx_test_status status;
+ void *context = NULL;
+
+ if (test->setup) {
+ status = test->setup(&context);
+ if (status != SCX_TEST_PASS)
+ return status;
+ }
+
+ status = test->run(context);
+
+ if (test->cleanup)
+ test->cleanup(context);
+
+ return status;
+}
+
+static bool test_valid(const struct scx_test *test)
+{
+ if (!test) {
+ fprintf(stderr, "NULL test detected\n");
+ return false;
+ }
+
+ if (!test->name) {
+ fprintf(stderr,
+ "Test with no name found. Must specify test name.\n");
+ return false;
+ }
+
+ if (!test->description) {
+ fprintf(stderr, "Test %s requires description.\n", test->name);
+ return false;
+ }
+
+ if (!test->run) {
+ fprintf(stderr, "Test %s has no run() callback\n", test->name);
+ return false;
+ }
+
+ return true;
+}
+
+int main(int argc, char **argv)
+{
+ const char *filter = NULL;
+ unsigned testnum = 0, i;
+ unsigned passed = 0, skipped = 0, failed = 0;
+ int opt;
+
+ signal(SIGINT, sigint_handler);
+ signal(SIGTERM, sigint_handler);
+
+ libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+
+ while ((opt = getopt(argc, argv, "qst:h")) != -1) {
+ switch (opt) {
+ case 'q':
+ quiet = true;
+ break;
+ case 's':
+ print_skipped = true;
+ break;
+ case 't':
+ filter = optarg;
+ break;
+ default:
+ fprintf(stderr, help_fmt, basename(argv[0]));
+ return opt != 'h';
+ }
+ }
+
+ for (i = 0; i < __scx_num_tests; i++) {
+ enum scx_test_status status;
+ struct scx_test *test = &__scx_tests[i];
+
+ if (filter && should_skip_test(test, filter)) {
+ /*
+ * Printing the skipped tests and their preambles can
+ * add a lot of noise to the runner output. Printing
+ * this is only really useful for CI, so let's skip it
+ * by default.
+ */
+ if (print_skipped) {
+ print_test_preamble(test, quiet);
+ print_test_result(test, SCX_TEST_SKIP, ++testnum);
+ }
+ continue;
+ }
+
+ print_test_preamble(test, quiet);
+ status = run_test(test);
+ print_test_result(test, status, ++testnum);
+ switch (status) {
+ case SCX_TEST_PASS:
+ passed++;
+ break;
+ case SCX_TEST_SKIP:
+ skipped++;
+ break;
+ case SCX_TEST_FAIL:
+ failed++;
+ break;
+ }
+ }
+ printf("\n\n=============================\n\n");
+ printf("RESULTS:\n\n");
+ printf("PASSED: %u\n", passed);
+ printf("SKIPPED: %u\n", skipped);
+ printf("FAILED: %u\n", failed);
+
+ return 0;
+}
+
+void scx_test_register(struct scx_test *test)
+{
+ SCX_BUG_ON(!test_valid(test), "Invalid test found");
+ SCX_BUG_ON(__scx_num_tests >= MAX_SCX_TESTS, "Maximum tests exceeded");
+
+ __scx_tests[__scx_num_tests++] = *test;
+}
diff --git a/tools/testing/selftests/sched_ext/scx_test.h b/tools/testing/selftests/sched_ext/scx_test.h
new file mode 100644
index 000000000000..90b8d6915bb7
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/scx_test.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ */
+
+#ifndef __SCX_TEST_H__
+#define __SCX_TEST_H__
+
+#include <errno.h>
+#include <scx/common.h>
+#include <scx/compat.h>
+
+enum scx_test_status {
+ SCX_TEST_PASS = 0,
+ SCX_TEST_SKIP,
+ SCX_TEST_FAIL,
+};
+
+#define EXIT_KIND(__ent) __COMPAT_ENUM_OR_ZERO("scx_exit_kind", #__ent)
+
+struct scx_test {
+ /**
+ * name - The name of the testcase.
+ */
+ const char *name;
+
+ /**
+ * description - A description of your testcase: what it tests and is
+ * meant to validate.
+ */
+ const char *description;
+
+ /*
+ * setup - Setup the test.
+ * @ctx: A pointer to a context object that will be passed to run and
+ * cleanup.
+ *
+ * An optional callback that allows a testcase to perform setup for its
+ * run. A test may return SCX_TEST_SKIP to skip the run.
+ */
+ enum scx_test_status (*setup)(void **ctx);
+
+ /*
+ * run - Run the test.
+ * @ctx: Context set in the setup() callback. If @ctx was not set in
+ * setup(), it is NULL.
+ *
+ * The main test. Callers should return one of:
+ *
+ * - SCX_TEST_PASS: Test passed
+ * - SCX_TEST_SKIP: Test should be skipped
+ * - SCX_TEST_FAIL: Test failed
+ *
+ * This callback must be defined.
+ */
+ enum scx_test_status (*run)(void *ctx);
+
+ /*
+ * cleanup - Perform cleanup following the test
+ * @ctx: Context set in the setup() callback. If @ctx was not set in
+ * setup(), it is NULL.
+ *
+ * An optional callback that allows a test to perform cleanup after
+ * being run. This callback is run even if the run() callback returns
+ * SCX_TEST_SKIP or SCX_TEST_FAIL. It is not run if setup() returns
+ * SCX_TEST_SKIP or SCX_TEST_FAIL.
+ */
+ void (*cleanup)(void *ctx);
+};
+
+void scx_test_register(struct scx_test *test);
+
+#define REGISTER_SCX_TEST(__test) \
+ __attribute__((constructor)) \
+ static void ___scxregister##__LINE__(void) \
+ { \
+ scx_test_register(__test); \
+ }
+
+#define SCX_ERR(__fmt, ...) \
+ do { \
+ fprintf(stderr, "ERR: %s:%d\n", __FILE__, __LINE__); \
+ fprintf(stderr, __fmt"\n", ##__VA_ARGS__); \
+ } while (0)
+
+#define SCX_FAIL(__fmt, ...) \
+ do { \
+ SCX_ERR(__fmt, ##__VA_ARGS__); \
+ return SCX_TEST_FAIL; \
+ } while (0)
+
+#define SCX_FAIL_IF(__cond, __fmt, ...) \
+ do { \
+ if (__cond) \
+ SCX_FAIL(__fmt, ##__VA_ARGS__); \
+ } while (0)
+
+#define SCX_GT(_x, _y) SCX_FAIL_IF((_x) <= (_y), "Expected %s > %s (%lu > %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_GE(_x, _y) SCX_FAIL_IF((_x) < (_y), "Expected %s >= %s (%lu >= %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_LT(_x, _y) SCX_FAIL_IF((_x) >= (_y), "Expected %s < %s (%lu < %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_LE(_x, _y) SCX_FAIL_IF((_x) > (_y), "Expected %s <= %s (%lu <= %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_EQ(_x, _y) SCX_FAIL_IF((_x) != (_y), "Expected %s == %s (%lu == %lu)", \
+ #_x, #_y, (u64)(_x), (u64)(_y))
+#define SCX_ASSERT(_x) SCX_FAIL_IF(!(_x), "Expected %s to be true (%lu)", \
+ #_x, (u64)(_x))
+
+#define SCX_ECODE_VAL(__ecode) ({ \
+ u64 __val = 0; \
+ bool __found = false; \
+ \
+ __found = __COMPAT_read_enum("scx_exit_code", #__ecode, &__val); \
+ SCX_ASSERT(__found); \
+ (s64)__val; \
+})
+
+#define SCX_KIND_VAL(__kind) ({ \
+ u64 __val = 0; \
+ bool __found = false; \
+ \
+ __found = __COMPAT_read_enum("scx_exit_kind", #__kind, &__val); \
+ SCX_ASSERT(__found); \
+ __val; \
+})
+
+#endif // # __SCX_TEST_H__
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
new file mode 100644
index 000000000000..2ed2991afafe
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl.bpf.c
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+bool saw_local = false;
+
+static bool task_is_test(const struct task_struct *p)
+{
+ return !bpf_strncmp(p->comm, 9, "select_cpu");
+}
+
+void BPF_STRUCT_OPS(select_cpu_dfl_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ const struct cpumask *idle_mask = scx_bpf_get_idle_cpumask();
+
+ if (task_is_test(p) &&
+ bpf_cpumask_test_cpu(scx_bpf_task_cpu(p), idle_mask)) {
+ saw_local = true;
+ }
+ scx_bpf_put_idle_cpumask(idle_mask);
+
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dfl_ops = {
+ .enqueue = select_cpu_dfl_enqueue,
+ .name = "select_cpu_dfl",
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl.c b/tools/testing/selftests/sched_ext/select_cpu_dfl.c
new file mode 100644
index 000000000000..a53a40c2d2f0
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl.c
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dfl.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dfl *skel;
+
+ skel = select_cpu_dfl__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dfl *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dfl_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ SCX_ASSERT(!skel->bss->saw_local);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dfl *skel = ctx;
+
+ select_cpu_dfl__destroy(skel);
+}
+
+struct scx_test select_cpu_dfl = {
+ .name = "select_cpu_dfl",
+ .description = "Verify the default ops.select_cpu() dispatches tasks "
+ "when idles cores are found, and skips ops.enqueue()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dfl)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
new file mode 100644
index 000000000000..4bb5abb2d369
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.bpf.c
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation, and with the SCX_OPS_ENQ_DFL_NO_DISPATCH ops flag
+ * specified.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+bool saw_local = false;
+
+/* Per-task scheduling context */
+struct task_ctx {
+ bool force_local; /* CPU changed by ops.select_cpu() */
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
+ __uint(map_flags, BPF_F_NO_PREALLOC);
+ __type(key, int);
+ __type(value, struct task_ctx);
+} task_ctx_stor SEC(".maps");
+
+/* Manually specify the signature until the kfunc is added to the scx repo. */
+s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
+ bool *found) __ksym;
+
+s32 BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ struct task_ctx *tctx;
+ s32 cpu;
+
+ tctx = bpf_task_storage_get(&task_ctx_stor, p, 0, 0);
+ if (!tctx) {
+ scx_bpf_error("task_ctx lookup failed");
+ return -ESRCH;
+ }
+
+ cpu = scx_bpf_select_cpu_dfl(p, prev_cpu, wake_flags,
+ &tctx->force_local);
+
+ return cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_enqueue, struct task_struct *p,
+ u64 enq_flags)
+{
+ u64 dsq_id = SCX_DSQ_GLOBAL;
+ struct task_ctx *tctx;
+
+ tctx = bpf_task_storage_get(&task_ctx_stor, p, 0, 0);
+ if (!tctx) {
+ scx_bpf_error("task_ctx lookup failed");
+ return;
+ }
+
+ if (tctx->force_local) {
+ dsq_id = SCX_DSQ_LOCAL;
+ tctx->force_local = false;
+ saw_local = true;
+ }
+
+ scx_bpf_dispatch(p, dsq_id, SCX_SLICE_DFL, enq_flags);
+}
+
+s32 BPF_STRUCT_OPS(select_cpu_dfl_nodispatch_init_task,
+ struct task_struct *p, struct scx_init_task_args *args)
+{
+ if (bpf_task_storage_get(&task_ctx_stor, p, 0,
+ BPF_LOCAL_STORAGE_GET_F_CREATE))
+ return 0;
+ else
+ return -ENOMEM;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dfl_nodispatch_ops = {
+ .select_cpu = select_cpu_dfl_nodispatch_select_cpu,
+ .enqueue = select_cpu_dfl_nodispatch_enqueue,
+ .init_task = select_cpu_dfl_nodispatch_init_task,
+ .name = "select_cpu_dfl_nodispatch",
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
new file mode 100644
index 000000000000..1d85bf4bf3a3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dfl_nodispatch.c
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dfl_nodispatch.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel;
+
+ skel = select_cpu_dfl_nodispatch__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dfl_nodispatch_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ SCX_ASSERT(skel->bss->saw_local);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dfl_nodispatch *skel = ctx;
+
+ select_cpu_dfl_nodispatch__destroy(skel);
+}
+
+struct scx_test select_cpu_dfl_nodispatch = {
+ .name = "select_cpu_dfl_nodispatch",
+ .description = "Verify behavior of scx_bpf_select_cpu_dfl() in "
+ "ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dfl_nodispatch)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
new file mode 100644
index 000000000000..f0b96a4a04b2
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch.bpf.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ u64 dsq_id = SCX_DSQ_LOCAL;
+ s32 cpu = prev_cpu;
+
+ if (scx_bpf_test_and_clear_cpu_idle(cpu))
+ goto dispatch;
+
+ cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+ if (cpu >= 0)
+ goto dispatch;
+
+ dsq_id = SCX_DSQ_GLOBAL;
+ cpu = prev_cpu;
+
+dispatch:
+ scx_bpf_dispatch(p, dsq_id, SCX_SLICE_DFL, 0);
+ return cpu;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_ops = {
+ .select_cpu = select_cpu_dispatch_select_cpu,
+ .name = "select_cpu_dispatch",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch.c
new file mode 100644
index 000000000000..0309ca8785b3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch.c
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch.bpf.skel.h"
+#include "scx_test.h"
+
+#define NUM_CHILDREN 1028
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch *skel;
+
+ skel = select_cpu_dispatch__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch *skel = ctx;
+ struct bpf_link *link;
+ pid_t pids[NUM_CHILDREN];
+ int i, status;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ pids[i] = fork();
+ if (pids[i] == 0) {
+ sleep(1);
+ exit(0);
+ }
+ }
+
+ for (i = 0; i < NUM_CHILDREN; i++) {
+ SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
+ SCX_EQ(status, 0);
+ }
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch *skel = ctx;
+
+ select_cpu_dispatch__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch = {
+ .name = "select_cpu_dispatch",
+ .description = "Test direct dispatching to built-in DSQs from "
+ "ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
new file mode 100644
index 000000000000..7b42ddce0f56
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.bpf.c
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_bad_dsq_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ /* Dispatching to a random DSQ should fail. */
+ scx_bpf_dispatch(p, 0xcafef00d, SCX_SLICE_DFL, 0);
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dispatch_bad_dsq_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_bad_dsq_ops = {
+ .select_cpu = select_cpu_dispatch_bad_dsq_select_cpu,
+ .exit = select_cpu_dispatch_bad_dsq_exit,
+ .name = "select_cpu_dispatch_bad_dsq",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
new file mode 100644
index 000000000000..47eb6ed7627d
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_bad_dsq.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch_bad_dsq.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel;
+
+ skel = select_cpu_dispatch_bad_dsq__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_bad_dsq_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch_bad_dsq *skel = ctx;
+
+ select_cpu_dispatch_bad_dsq__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch_bad_dsq = {
+ .name = "select_cpu_dispatch_bad_dsq",
+ .description = "Verify graceful failure if we direct-dispatch to a "
+ "bogus DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch_bad_dsq)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
new file mode 100644
index 000000000000..653e3dc0b4dc
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.bpf.c
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates the behavior of direct dispatching with a default
+ * select_cpu implementation.
+ *
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+s32 BPF_STRUCT_OPS(select_cpu_dispatch_dbl_dsp_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ /* Dispatching twice in a row is disallowed. */
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, 0);
+ scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, 0);
+
+ return prev_cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_dispatch_dbl_dsp_exit, struct scx_exit_info *ei)
+{
+ UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_dispatch_dbl_dsp_ops = {
+ .select_cpu = select_cpu_dispatch_dbl_dsp_select_cpu,
+ .exit = select_cpu_dispatch_dbl_dsp_exit,
+ .name = "select_cpu_dispatch_dbl_dsp",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
new file mode 100644
index 000000000000..48ff028a3c46
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_dispatch_dbl_dsp.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2023 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_dispatch_dbl_dsp.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel;
+
+ skel = select_cpu_dispatch_dbl_dsp__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel = ctx;
+ struct bpf_link *link;
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dispatch_dbl_dsp_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_ERROR));
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_dispatch_dbl_dsp *skel = ctx;
+
+ select_cpu_dispatch_dbl_dsp__destroy(skel);
+}
+
+struct scx_test select_cpu_dispatch_dbl_dsp = {
+ .name = "select_cpu_dispatch_dbl_dsp",
+ .description = "Verify graceful failure if we dispatch twice to a "
+ "DSQ in ops.select_cpu()",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_dispatch_dbl_dsp)
diff --git a/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c b/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
new file mode 100644
index 000000000000..7f3ebf4fc2ea
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_vtime.bpf.c
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A scheduler that validates that enqueue flags are properly stored and
+ * applied at dispatch time when a task is directly dispatched from
+ * ops.select_cpu(). We validate this by using scx_bpf_dispatch_vtime(), and
+ * making the test a very basic vtime scheduler.
+ *
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+volatile bool consumed;
+
+static u64 vtime_now;
+
+#define VTIME_DSQ 0
+
+static inline bool vtime_before(u64 a, u64 b)
+{
+ return (s64)(a - b) < 0;
+}
+
+static inline u64 task_vtime(const struct task_struct *p)
+{
+ u64 vtime = p->scx.dsq_vtime;
+
+ if (vtime_before(vtime, vtime_now - SCX_SLICE_DFL))
+ return vtime_now - SCX_SLICE_DFL;
+ else
+ return vtime;
+}
+
+s32 BPF_STRUCT_OPS(select_cpu_vtime_select_cpu, struct task_struct *p,
+ s32 prev_cpu, u64 wake_flags)
+{
+ s32 cpu;
+
+ cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
+ if (cpu >= 0)
+ goto ddsp;
+
+ cpu = prev_cpu;
+ scx_bpf_test_and_clear_cpu_idle(cpu);
+ddsp:
+ scx_bpf_dispatch_vtime(p, VTIME_DSQ, SCX_SLICE_DFL, task_vtime(p), 0);
+ return cpu;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_dispatch, s32 cpu, struct task_struct *p)
+{
+ if (scx_bpf_consume(VTIME_DSQ))
+ consumed = true;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_running, struct task_struct *p)
+{
+ if (vtime_before(vtime_now, p->scx.dsq_vtime))
+ vtime_now = p->scx.dsq_vtime;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_stopping, struct task_struct *p,
+ bool runnable)
+{
+ p->scx.dsq_vtime += (SCX_SLICE_DFL - p->scx.slice) * 100 / p->scx.weight;
+}
+
+void BPF_STRUCT_OPS(select_cpu_vtime_enable, struct task_struct *p)
+{
+ p->scx.dsq_vtime = vtime_now;
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(select_cpu_vtime_init)
+{
+ return scx_bpf_create_dsq(VTIME_DSQ, -1);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops select_cpu_vtime_ops = {
+ .select_cpu = select_cpu_vtime_select_cpu,
+ .dispatch = select_cpu_vtime_dispatch,
+ .running = select_cpu_vtime_running,
+ .stopping = select_cpu_vtime_stopping,
+ .enable = select_cpu_vtime_enable,
+ .init = select_cpu_vtime_init,
+ .name = "select_cpu_vtime",
+ .timeout_ms = 1000U,
+};
diff --git a/tools/testing/selftests/sched_ext/select_cpu_vtime.c b/tools/testing/selftests/sched_ext/select_cpu_vtime.c
new file mode 100644
index 000000000000..b4629c2364f5
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/select_cpu_vtime.c
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "select_cpu_vtime.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status setup(void **ctx)
+{
+ struct select_cpu_vtime *skel;
+
+ skel = select_cpu_vtime__open_and_load();
+ SCX_FAIL_IF(!skel, "Failed to open and load skel");
+ *ctx = skel;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ struct select_cpu_vtime *skel = ctx;
+ struct bpf_link *link;
+
+ SCX_ASSERT(!skel->bss->consumed);
+
+ link = bpf_map__attach_struct_ops(skel->maps.select_cpu_vtime_ops);
+ SCX_FAIL_IF(!link, "Failed to attach scheduler");
+
+ sleep(1);
+
+ SCX_ASSERT(skel->bss->consumed);
+
+ bpf_link__destroy(link);
+
+ return SCX_TEST_PASS;
+}
+
+static void cleanup(void *ctx)
+{
+ struct select_cpu_vtime *skel = ctx;
+
+ select_cpu_vtime__destroy(skel);
+}
+
+struct scx_test select_cpu_vtime = {
+ .name = "select_cpu_vtime",
+ .description = "Test doing direct vtime-dispatching from "
+ "ops.select_cpu(), to a non-built-in DSQ",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&select_cpu_vtime)
diff --git a/tools/testing/selftests/sched_ext/test_example.c b/tools/testing/selftests/sched_ext/test_example.c
new file mode 100644
index 000000000000..ce36cdf03cdc
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/test_example.c
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <bpf/bpf.h>
+#include <scx/common.h>
+#include "scx_test.h"
+
+static bool setup_called = false;
+static bool run_called = false;
+static bool cleanup_called = false;
+
+static int context = 10;
+
+static enum scx_test_status setup(void **ctx)
+{
+ setup_called = true;
+ *ctx = &context;
+
+ return SCX_TEST_PASS;
+}
+
+static enum scx_test_status run(void *ctx)
+{
+ int *arg = ctx;
+
+ SCX_ASSERT(setup_called);
+ SCX_ASSERT(!run_called && !cleanup_called);
+ SCX_EQ(*arg, context);
+
+ run_called = true;
+ return SCX_TEST_PASS;
+}
+
+static void cleanup (void *ctx)
+{
+ SCX_BUG_ON(!run_called || cleanup_called, "Wrong callbacks invoked");
+}
+
+struct scx_test example = {
+ .name = "example",
+ .description = "Validate the basic function of the test suite itself",
+ .setup = setup,
+ .run = run,
+ .cleanup = cleanup,
+};
+REGISTER_SCX_TEST(&example)
diff --git a/tools/testing/selftests/sched_ext/util.c b/tools/testing/selftests/sched_ext/util.c
new file mode 100644
index 000000000000..e47769c91918
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/util.c
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Returns read len on success, or -errno on failure. */
+static ssize_t read_text(const char *path, char *buf, size_t max_len)
+{
+ ssize_t len;
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -errno;
+
+ len = read(fd, buf, max_len - 1);
+
+ if (len >= 0)
+ buf[len] = 0;
+
+ close(fd);
+ return len < 0 ? -errno : len;
+}
+
+/* Returns written len on success, or -errno on failure. */
+static ssize_t write_text(const char *path, char *buf, ssize_t len)
+{
+ int fd;
+ ssize_t written;
+
+ fd = open(path, O_WRONLY | O_APPEND);
+ if (fd < 0)
+ return -errno;
+
+ written = write(fd, buf, len);
+ close(fd);
+ return written < 0 ? -errno : written;
+}
+
+long file_read_long(const char *path)
+{
+ char buf[128];
+
+
+ if (read_text(path, buf, sizeof(buf)) <= 0)
+ return -1;
+
+ return atol(buf);
+}
+
+int file_write_long(const char *path, long val)
+{
+ char buf[64];
+ int ret;
+
+ ret = sprintf(buf, "%lu", val);
+ if (ret < 0)
+ return ret;
+
+ if (write_text(path, buf, sizeof(buf)) <= 0)
+ return -1;
+
+ return 0;
+}
diff --git a/tools/testing/selftests/sched_ext/util.h b/tools/testing/selftests/sched_ext/util.h
new file mode 100644
index 000000000000..bc13dfec1267
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/util.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <void@manifault.com>
+ */
+
+#ifndef __SCX_TEST_UTIL_H__
+#define __SCX_TEST_UTIL_H__
+
+long file_read_long(const char *path);
+int file_write_long(const char *path, long val);
+
+#endif // __SCX_TEST_H__
--
2.45.2
Implementation Analysis
Overview
This patch (authored by David Vernet) establishes the tools/testing/selftests/sched_ext/ directory and provides a comprehensive selftest suite for sched_ext. The selftests are built with libbpf and BPF skeletons — each test is a minimal BPF scheduler (.bpf.c) paired with a C userspace driver (.c). They exercise specific features and error conditions rather than general scheduling correctness. 51 files are added, comprising over 3200 lines of test infrastructure and test cases.
Code Walkthrough
Test infrastructure — the shared framework files:
runner.c/scx_test.h: The test runner harness. DefinesSCX_TEST_RUN_ALL()and helpers for loading/attaching BPF skeletons, checking exit codes, and reporting PASS/FAIL. Tests register themselves via a linked list ofstruct scx_testentries.util.c/util.h: Utility functions shared across tests.Makefile(218 lines): Builds all.bpf.cfiles with clang, generates BPF skeletons, links each test binary. Follows the standardtools/testing/selftestsMakefile conventions. Includes../../../build/Build.include.config: Kernel Kconfig fragment specifying minimum requirements:CONFIG_SCHED_DEBUG=y CONFIG_SCHED_CLASS_EXT=y CONFIG_CGROUPS=y CONFIG_CGROUP_SCHED=y CONFIG_NO_HZ_FULL=y CONFIG_SCHED_CORE=y
Test cases and what they verify:
-
minimal: The simplest possible BPF scheduler — justops.initandops.exit. Verifies that a scheduler with no other ops loads, runs briefly, and exits cleanly. -
create_dsq: Creates a custom DSQ withscx_bpf_create_dsq(), dispatches tasks to it viaops.enqueue(), and destroys it inops.exit(). Verifies the DSQ create/consume/destroy lifecycle. -
dsp_local_on: Usesscx_bpf_dispatch_local_on(p, cpu, ...)to dispatch tasks directly to a specific CPU's local DSQ. Verifies that targeted local-DSQ dispatch works correctly and tasks actually run on the intended CPU. -
ddsp_bogus_dsq_fail: Attempts to dispatch a task to a DSQ ID that does not exist. Verifies that the BPF scheduler exits with an ops error (not a kernel panic or silent failure). -
ddsp_vtimelocal_fail: Attempts to callscx_bpf_dispatch_vtime()targetingSCX_DSQ_LOCAL. Verifies that this correctly triggers an ops error (built-in DSQs cannot be PRIQ). -
enq_last_no_enq_fails: Implementsops.enqueue()withSCX_OPS_ENQ_LASTset in flags, but the enqueue callback deliberately does not dispatch the task whenSCX_ENQ_LASTis received. Verifies that the watchdog/error detection catches this stall. -
enq_select_cpu_fails: Theops.select_cpu()callback returns an invalid CPU (e.g., out of range or not in the task's allowed cpumask). Verifies that the kernel catches this invalid selection and handles it gracefully. -
exit: Tests various exit scenarios —scx_bpf_exit()called with different exit codes, verifying that the correct exit kind and code are reported back to userspace viaops.exit(). -
prog_run: A basic smoke test that loads a complete BPF scheduler (with select_cpu, enqueue, dispatch), lets it run for a brief period with actual tasks, and verifies it ran without errors. -
hotplug: Tests CPU hotplug interaction. Exercises thecpu_online/offlinecallbacks, the auto-restart path when callbacks are absent, and thehotplug_seqrace detection mechanism. -
init_enable_count: Verifies thatops.init_task()andops.enable()are called the correct number of times as tasks transition in and out of sched_ext scheduling. -
maximal: Implements every optional op callback to ensure that the full ops table can be populated without crashes. This is a compilation and runtime coverage test. -
maybe_null/maybe_null_fail_dsp/maybe_null_fail_yld: Tests for nullable pointer handling in ops callbacks. Verifies that the BPF verifier correctly rejects programs that dereference potentially-null pointers without checks, and accepts programs that do null-check correctly. -
reload_loop: Repeatedly loads and unloads a BPF scheduler in a tight loop, verifying that the load/unload cycle is safe and leak-free. -
select_cpu_dfl/select_cpu_dfl_nodispatch/select_cpu_dispatch/select_cpu_dispatch_bad_dsq/select_cpu_dispatch_dbl_dsp: A suite of tests for theselect_cpupath. Tests include: using the default CPU selection, dispatching vs. not dispatching fromselect_cpu, dispatching to an invalid DSQ fromselect_cpu, and double-dispatch (dispatching twice for the same task fromselect_cpu). -
select_cpu_vtime: Tests vtime dispatch fromselect_cpu. Verifies thatscx_bpf_dispatch_vtime()works correctly when called from theselect_cpucontext. -
test_example: A meta-test that exercises the test framework itself.
Key Concepts
Test structure: Each test consists of:
- A
.bpf.cfile: the BPF scheduler program, compiled with clang and loaded via libbpf skeletons. - A
.cfile: the userspace driver that loads the skeleton, attaches it, lets it run briefly, then checks the exit condition.
Error detection tests (the *_fail tests): These tests intentionally trigger ops errors and verify that sched_ext catches them and exits with the expected error kind. This exercises the error handling and watchdog infrastructure.
scx_test.h conventions: Tests declare a struct scx_test with .name, .description, and .run function pointer. The runner collects all registered tests and executes them, reporting results.
Kernel config requirements: CONFIG_SCHED_CORE=y is listed in config, reflecting that this patch series requires core-sched to be buildable alongside sched_ext (from patch 27/30).
Locking and Concurrency Notes
The selftests themselves are userspace programs — locking is not a direct concern. However, the tests exercise kernel-side locking indirectly:
- Tests that use
SCX_OPS_ENQ_LASTexercise the path where rq lock is held with no runnable tasks. - The
reload_looptest exercises concurrent load/unload which exercises thescx_cgroup_rwsem/scx_fork_rwsemlocking inscx_ops_enable/disable. - The
hotplugtest exercises the interaction between hotplug locking (cpus_read_lock) and the sched_ext enable path.
Integration with Kernel Subsystems
The selftests integrate with the Linux kernel selftest framework (tools/testing/selftests/). The config file is picked up by kselftest infrastructure to set kernel build options when running selftests in CI. The Makefile follows the standard pattern for BPF-based selftests (similar to tools/testing/selftests/bpf/).
Required build dependencies: clang (for BPF compilation), libbpf, bpf skeletons (via bpftool). The CONFIG_SCHED_CLASS_EXT=y kernel option is required at runtime.
What Maintainers Need to Know
- Run selftests before submitting patches. The suite catches a wide range of error conditions, verifier rejections, and basic correctness issues. Run with:
make -C tools/testing/selftests/sched_ext && ./runner. - Add a selftest for every new error condition. The
ddsp_bogus_dsq_failandddsp_vtimelocal_failpatterns demonstrate the standard approach: write a BPF scheduler that intentionally triggers the error, verify the exit code matches the expected ops error. - Add a selftest for every new ops callback.
maximal.bpf.cshould be updated to include any new callback added tostruct sched_ext_ops, ensuring it compiles and runs without error. - The
configfile must be updated when new Kconfig requirements are added to sched_ext. TheCONFIG_SCHED_CORE=yentry was added in this patch precisely because patch 27/30 removed the!SCHED_COREdependency. maybe_nulltests are important for verifier correctness. If you add a new ops callback that takes a potentially-null pointer (e.g.,struct task_struct *arguments that may be null in some invocations), add correspondingmaybe_nulltests.- Test isolation: Each test loads a fresh BPF scheduler skeleton, runs briefly, and exits. Tests must not assume any scheduler state from previous tests. The
reload_looptest specifically validates that the kernel cleans up state correctly between loads.
Connection to Other Patches
- All patches 1-29: The selftests exercise features from every patch in the series.
create_dsqandselect_cpu_vtimetest patch 28 (vtime DSQs).hotplugtests patch 25 (cpu_online/offline).enq_last_no_enq_failstests theSCX_ENQ_LASTflag from earlier patches.ddsp_vtimelocal_failtests the built-in DSQ PRIQ restriction from patch 28. - Patch 29/30 (documentation): The
tools/sched_ext/README.mdfrom that patch and thetools/testing/selftests/sched_ext/directory from this patch together form the complete developer and QA tooling for sched_ext.