[PATCH 39/39] sched_ext: Add selftests

From: Tejun Heo
Date: Wed May 01 2024 - 11:23:06 EST

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From: David Vernet <dvernet@xxxxxxxx>

Add basic selftests.

Signed-off-by: David Vernet <dvernet@xxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
---
tools/testing/selftests/sched_ext/.gitignore | 6 +
tools/testing/selftests/sched_ext/Makefile | 216 ++++++++++++++++++
tools/testing/selftests/sched_ext/config | 9 +
.../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 +++++
.../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 | 55 +++++
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 | 164 +++++++++++++
tools/testing/selftests/sched_ext/maximal.c | 51 +++++
.../selftests/sched_ext/maybe_null.bpf.c | 26 +++
.../testing/selftests/sched_ext/maybe_null.c | 40 ++++
.../selftests/sched_ext/maybe_null_fail.bpf.c | 25 ++
.../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 ++
46 files changed, 2983 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/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/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.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..a95fa2a1adad
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/Makefile
@@ -0,0 +1,216 @@
+# 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 := \
+ enq_last_no_enq_fails \
+ enq_select_cpu_fails \
+ ddsp_bogus_dsq_fail \
+ ddsp_vtimelocal_fail \
+ 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/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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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/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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+
+#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..1f5f91f4f66a
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/hotplug.bpf.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@xxxxxxxx>
+ */
+
+#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)
+{
+ 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(hotplug_cpu_online, s32 cpu)
+{
+ exit_from_hotplug(cpu, true);
+}
+
+void BPF_STRUCT_OPS(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@xxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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..ef9da0a50846
--- /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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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 |= __COMPAT_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, &param);
+ 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, &param);
+ 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..00bfa9cb95d3
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maximal.bpf.c
@@ -0,0 +1,164 @@
+/* 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@xxxxxxxx>
+ */
+
+#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(maximal_cgroup_init, struct cgroup *cgrp,
+ struct scx_cgroup_init_args *args)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_cgroup_exit, struct cgroup *cgrp)
+{}
+
+s32 BPF_STRUCT_OPS(maximal_cgroup_prep_move, struct task_struct *p,
+ struct cgroup *from, struct cgroup *to)
+{
+ return 0;
+}
+
+void BPF_STRUCT_OPS(maximal_cgroup_move, struct task_struct *p,
+ struct cgroup *from, struct cgroup *to)
+{}
+
+void BPF_STRUCT_OPS(maximal_cgroup_cancel_move, struct task_struct *p,
+ struct cgroup *from, struct cgroup *to)
+{}
+
+void BPF_STRUCT_OPS(maximal_cgroup_set_weight, struct cgroup *cgrp, u32 weight)
+{}
+
+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,
+ .cgroup_init = maximal_cgroup_init,
+ .cgroup_exit = maximal_cgroup_exit,
+ .cgroup_prep_move = maximal_cgroup_prep_move,
+ .cgroup_move = maximal_cgroup_move,
+ .cgroup_cancel_move = maximal_cgroup_cancel_move,
+ .cgroup_set_weight = maximal_cgroup_set_weight,
+ .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@xxxxxxxx>
+ */
+#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..ad5e694226bb
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.bpf.c
@@ -0,0 +1,26 @@
+/* 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;
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops maybe_null_success = {
+ .dispatch = maybe_null_success_dispatch,
+ .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..3f26b784f9c5
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null.c
@@ -0,0 +1,40 @@
+/* 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.bpf.skel.h"
+#include "scx_test.h"
+
+static enum scx_test_status run(void *ctx)
+{
+ struct maybe_null *skel;
+ struct maybe_null_fail *fail_skel;
+
+ 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_skel = maybe_null_fail__open_and_load();
+ if (fail_skel) {
+ maybe_null_fail__destroy(fail_skel);
+ SCX_ERR("Should failed to open and load maybe_null_fail 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.bpf.c b/tools/testing/selftests/sched_ext/maybe_null_fail.bpf.c
new file mode 100644
index 000000000000..1607fe07bead
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/maybe_null_fail.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 = "minimal",
+};
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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxxxx>
+ * Copyright (c) 2023 David Vernet <dvernet@xxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2023 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxx>
+ * Copyright (c) 2024 Tejun Heo <tj@xxxxxxxxxx>
+ */
+#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@xxxxxxxxxx>
+ * Copyright (c) 2024 David Vernet <dvernet@xxxxxxxx>
+ */
+#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@xxxxxxxx>
+ */
+#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@xxxxxxxxxxxxx>
+ */
+
+#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__
--
2.44.0

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