linux-stable.git/kernel/sched/pelt.c, branch linux-rolling-lts

sched: Clean up and standardize #if/#else/#endif markers in sched/pelt.[ch]

2025-06-13T06:47:17+00:00

 - Use the standard #ifdef marker format for larger blocks,
   where appropriate:

        #if CONFIG_FOO
        ...
        #else /* !CONFIG_FOO: */
        ...
        #endif /* !CONFIG_FOO */

 - Fix whitespace noise and other inconsistencies.

Signed-off-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Cc: Dietmar Eggemann 
Cc: Juri Lelli 
Cc: Linus Torvalds 
Cc: Mel Gorman 
Cc: Sebastian Andrzej Siewior 
Cc: Shrikanth Hegde 
Cc: Steven Rostedt 
Cc: Valentin Schneider 
Cc: Vincent Guittot 
Link: https://lore.kernel.org/r/20250528080924.2273858-13-mingo@kernel.org

sched: Make clangd usable

2025-06-11T09:20:53+00:00

Due to the weird Makefile setup of sched the various files do not
compile as stand alone units. The new generation of editors are trying
to do just this -- mostly to offer fancy things like completions but
also better syntax highlighting and code navigation.

Specifically, I've been playing around with neovim and clangd.

Setting up clangd on the kernel source is a giant pain in the arse
(this really should be improved), but once you do manage, you run into
dumb stuff like the above.

Fix up the scheduler files to at least pretend to work.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Ingo Molnar 
Tested-by: Juri Lelli 
Link: https://lkml.kernel.org/r/20250523164348.GN39944@noisy.programming.kicks-ass.net

sched/fair: Use the new cfs_rq.h_nr_runnable

2024-12-09T10:48:11+00:00

Use the new h_nr_runnable that tracks only queued and runnable tasks in the
statistics that are used to balance the system:

 - PELT runnable_avg
 - deciding if a group is overloaded or has spare capacity
 - numa stats
 - reduced capacity management
 - load balance
 - nohz kick

It should be noticed that the rq->nr_running still counts the delayed
dequeued tasks as delayed dequeue is a fair feature that is meaningless
at core level.

Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann 
Link: https://lore.kernel.org/r/20241202174606.4074512-6-vincent.guittot@linaro.org

sched/fair: Rename h_nr_running into h_nr_queued

2024-12-09T10:48:11+00:00

With delayed dequeued feature, a sleeping sched_entity remains queued
in the rq until its lag has elapsed but can't run.
Rename h_nr_running into h_nr_queued to reflect this new behavior.

Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann 
Link: https://lore.kernel.org/r/20241202174606.4074512-4-vincent.guittot@linaro.org

sched/eevdf: More PELT vs DELAYED_DEQUEUE

2024-12-09T10:48:09+00:00

Vincent and Dietmar noted that while
commit fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE") fixes
the entity runnable stats, it does not adjust the cfs_rq runnable stats,
which are based off of h_nr_running.

Track h_nr_delayed such that we can discount those and adjust the
signal.

Fixes: fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE")
Closes: https://lore.kernel.org/lkml/a9a45193-d0c6-4ba2-a822-464ad30b550e@arm.com/
Closes: https://lore.kernel.org/lkml/CAKfTPtCNUvWE_GX5LyvTF-WdxUT=ZgvZZv-4t=eWntg5uOFqiQ@mail.gmail.com/
[ Fixes checkpatch warnings and rebased ]
Signed-off-by: Peter Zijlstra (Intel) 
Reported-by: Dietmar Eggemann 
Reported-by: Vincent Guittot 
Signed-off-by: "Peter Zijlstra (Intel)" 
Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann 
Tested-by: K Prateek Nayak 
Link: https://lore.kernel.org/r/20241202174606.4074512-3-vincent.guittot@linaro.org

sched: Split scheduler and execution contexts

2024-10-14T10:52:42+00:00

Let's define the "scheduling context" as all the scheduler state
in task_struct for the task chosen to run, which we'll call the
donor task, and the "execution context" as all state required to
actually run the task.

Currently both are intertwined in task_struct. We want to
logically split these such that we can use the scheduling
context of the donor task selected to be scheduled, but use
the execution context of a different task to actually be run.

To this purpose, introduce rq->donor field to point to the
task_struct chosen from the runqueue by the scheduler, and will
be used for scheduler state, and preserve rq->curr to indicate
the execution context of the task that will actually be run.

This patch introduces the donor field as a union with curr, so it
doesn't cause the contexts to be split yet, but adds the logic to
handle everything separately.

[add additional comments and update more sched_class code to use
 rq::proxy]
[jstultz: Rebased and resolved minor collisions, reworked to use
 accessors, tweaked update_curr_common to use rq_proxy fixing rt
 scheduling issues]

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Juri Lelli 
Signed-off-by: Connor O'Brien 
Signed-off-by: John Stultz 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Metin Kaya 
Tested-by: K Prateek Nayak 
Tested-by: Metin Kaya 
Link: https://lore.kernel.org/r/20241009235352.1614323-8-jstultz@google.com

sched: Move update_other_load_avgs() to kernel/sched/pelt.c

2024-09-12T06:00:21+00:00

96fd6c65efc6 ("sched: Factor out update_other_load_avgs() from
__update_blocked_others()") added update_other_load_avgs() in
kernel/sched/syscalls.c right above effective_cpu_util(). This location
didn't fit that well in the first place, and with 5d871a63997f ("sched/fair:
Move effective_cpu_util() and effective_cpu_util() in fair.c") moving
effective_cpu_util() to kernel/sched/fair.c, it looks even more out of
place.

Relocate the function to kernel/sched/pelt.c where all its callees are.

No functional changes.

Signed-off-by: Tejun Heo 
Cc: Peter Zijlstra 
Cc: Ingo Molnar

sched: Fix spelling in comments

2024-05-27T15:00:21+00:00

Do a spell-checking pass.

Signed-off-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/cpufreq: Rename arch_update_thermal_pressure() => arch_update_hw_pressure()

2024-04-24T10:08:01+00:00

Now that cpufreq provides a pressure value to the scheduler, rename
arch_update_thermal_pressure into HW pressure to reflect that it returns
a pressure applied by HW (i.e. with a high frequency change) and not
always related to thermal mitigation but also generated by max current
limitation as an example. Such high frequency signal needs filtering to be
smoothed and provide an value that reflects the average available capacity
into the scheduler time scale.

Signed-off-by: Vincent Guittot 
Signed-off-by: Ingo Molnar 
Tested-by: Lukasz Luba 
Reviewed-by: Qais Yousef 
Reviewed-by: Lukasz Luba 
Link: https://lore.kernel.org/r/20240326091616.3696851-5-vincent.guittot@linaro.org

sched/balancing: Fix a couple of outdated function names in comments

2024-03-12T11:00:01+00:00

The 'idle_balance()' function hasn't existed for years, and there's no
load_balance_newidle() either - both are sched_balance_newidle() today.

Reported-by: Honglei Wang 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/ZfAwNufbiyt/5biu@gmail.com