linux/kernel/sched/Makefile, branch master

sched: Enable context analysis for core.c and fair.c

2026-01-05T15:43:36Z

This demonstrates a larger conversion to use Clang's context analysis. The benefit is additional static checking of locking rules, along with better documentation. Notably, kernel/sched contains sufficiently complex synchronization patterns, and application to core.c & fair.c demonstrates that the latest Clang version has become powerful enough to start applying this to more complex subsystems (with some modest annotations and changes). Signed-off-by: Marco Elver Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251219154418.3592607-37-elver@google.com

tracing: Disable branch profiling in noinstr code

2025-03-22T08:49:26Z

CONFIG_TRACE_BRANCH_PROFILING inserts a call to ftrace_likely_update() for each use of likely() or unlikely(). That breaks noinstr rules if the affected function is annotated as noinstr. Disable branch profiling for files with noinstr functions. In addition to some individual files, this also includes the entire arch/x86 subtree, as well as the kernel/entry, drivers/cpuidle, and drivers/idle directories, all of which are noinstr-heavy. Due to the nature of how sched binaries are built by combining multiple .c files into one, branch profiling is disabled more broadly across the sched code than would otherwise be needed. This fixes many warnings like the following: vmlinux.o: warning: objtool: do_syscall_64+0x40: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: warning: objtool: __rdgsbase_inactive+0x33: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: warning: objtool: handle_bug.isra.0+0x198: call to ftrace_likely_update() leaves .noinstr.text section ... Reported-by: Ingo Molnar Suggested-by: Steven Rostedt Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Acked-by: Thomas Gleixner Cc: Linus Torvalds Link: https://lore.kernel.org/r/fb94fc9303d48a5ed370498f54500cc4c338eb6d.1742586676.git.jpoimboe@kernel.org

sched/headers: Introduce kernel/sched/build_policy.c and build multiple .c files there

2022-02-23T09:58:33Z

Similarly to kernel/sched/build_utility.c, collect all 'scheduling policy' related source code files into kernel/sched/build_policy.c: kernel/sched/idle.c kernel/sched/rt.c kernel/sched/cpudeadline.c kernel/sched/pelt.c kernel/sched/cputime.c kernel/sched/deadline.c With the exception of fair.c, which we continue to build as a separate file for build efficiency and parallelism reasons. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra

sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there

2022-02-23T09:58:33Z

Collect all utility functionality source code files into a single kernel/sched/build_utility.c file, via #include-ing the .c files: kernel/sched/clock.c kernel/sched/completion.c kernel/sched/loadavg.c kernel/sched/swait.c kernel/sched/wait_bit.c kernel/sched/wait.c CONFIG_CPU_FREQ: kernel/sched/cpufreq.c CONFIG_CPU_FREQ_GOV_SCHEDUTIL: kernel/sched/cpufreq_schedutil.c CONFIG_CGROUP_CPUACCT: kernel/sched/cpuacct.c CONFIG_SCHED_DEBUG: kernel/sched/debug.c CONFIG_SCHEDSTATS: kernel/sched/stats.c CONFIG_SMP: kernel/sched/cpupri.c kernel/sched/stop_task.c kernel/sched/topology.c CONFIG_SCHED_CORE: kernel/sched/core_sched.c CONFIG_PSI: kernel/sched/psi.c CONFIG_MEMBARRIER: kernel/sched/membarrier.c CONFIG_CPU_ISOLATION: kernel/sched/isolation.c CONFIG_SCHED_AUTOGROUP: kernel/sched/autogroup.c The goal is to amortize the 60+ KLOC header bloat from over a dozen build units into a single build unit. The build time of build_utility.c also roughly matches the build time of core.c and fair.c - allowing better load-balancing of scheduler-only rebuilds. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra

sched/headers: sched/clock: Mark all functions 'notrace', remove CC_FLAGS_FTRACE build asymmetry

2022-02-23T07:22:04Z

Mark all non-init functions in kernel/sched.c as 'notrace', instead of turning them all off via CC_FLAGS_FTRACE. This is going to allow the treatment of this file as any other scheduler file, and it can be #include-ed in compound compilation units as well. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra

sched, kcsan: Enable memory barrier instrumentation

2021-12-10T00:42:28Z

There's no fundamental reason to disable KCSAN for scheduler code, except for excessive noise and performance concerns (instrumenting scheduler code is usually a good way to stress test KCSAN itself). However, several core sched functions imply memory barriers that are invisible to KCSAN without instrumentation, but are required to avoid false positives. Therefore, unconditionally enable instrumentation of memory barriers in scheduler code. Also update the comment to reflect this and be a bit more brief. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

sched: Disable -Wunused-but-set-variable

2021-10-15T09:25:15Z

The compilers can't deal with obvious DCE vs that warning, resulting in code like: if (0) { sched sched_statistics *stats; stats = __schedstats_from_se(se); ... } triggering the warning. Kill the warning to make the robots stop reporting this. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Nathan Chancellor Link: https://lkml.kernel.org/r/YWWPLnaZGybHsTkv@hirez.programming.kicks-ass.net

sched: Trivial core scheduling cookie management

2021-05-12T09:43:31Z

In order to not have to use pid_struct, create a new, smaller, structure to manage task cookies for core scheduling. Signed-off-by: Peter Zijlstra (Intel) Tested-by: Don Hiatt Tested-by: Hongyu Ning Tested-by: Vincent Guittot Link: https://lkml.kernel.org/r/20210422123308.919768100@infradead.org

kcsan: Improve various small stylistic details

2019-11-20T09:47:23Z

Tidy up a few bits: - Fix typos and grammar, improve wording. - Remove spurious newlines that are col80 warning artifacts where the resulting line-break is worse than the disease it's curing. - Use core kernel coding style to improve readability and reduce spurious code pattern variations. - Use better vertical alignment for structure definitions and initialization sequences. - Misc other small details. No change in functionality intended. Cc: linux-kernel@vger.kernel.org Cc: Marco Elver Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Thomas Gleixner Cc: Paul E. McKenney Cc: Will Deacon Signed-off-by: Ingo Molnar

build, kcsan: Add KCSAN build exceptions

2019-11-16T15:23:14Z

This blacklists several compilation units from KCSAN. See the respective inline comments for the reasoning. Signed-off-by: Marco Elver Acked-by: Paul E. McKenney Signed-off-by: Paul E. McKenney