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| author | Peter Zijlstra <peterz@infradead.org> | 2021-02-24 13:21:35 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 14:40:21 +0300 |
| commit | 3f1bc119cd7fc987c8ed25ffb717f99403bb308c (patch) | |
| tree | 8ee04aee094a12ea4ad9b83523cfb76f4dd0a2b3 | |
| parent | 58b1a45086b5f80f2b2842aa7ed0da51a64a302b (diff) | |
| download | linux-3f1bc119cd7fc987c8ed25ffb717f99403bb308c.tar.xz | |
sched: Optimize migration_cpu_stop()
When the purpose of migration_cpu_stop() is to migrate the task to
'any' valid CPU, don't migrate the task when it's already running on a
valid CPU.
Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210224131355.569238629@infradead.org
| -rw-r--r-- | kernel/sched/core.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 84b657f05625..ac05afbd982e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1936,14 +1936,25 @@ static int migration_cpu_stop(void *data) complete = true; } - if (dest_cpu < 0) + if (dest_cpu < 0) { + if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) + goto out; + dest_cpu = cpumask_any_distribute(&p->cpus_mask); + } if (task_on_rq_queued(p)) rq = __migrate_task(rq, &rf, p, dest_cpu); else p->wake_cpu = dest_cpu; + /* + * XXX __migrate_task() can fail, at which point we might end + * up running on a dodgy CPU, AFAICT this can only happen + * during CPU hotplug, at which point we'll get pushed out + * anyway, so it's probably not a big deal. + */ + } else if (pending) { /* * This happens when we get migrated between migrate_enable()'s |