Messages in this thread Patch in this message | | | From | Vincent Donnefort <> | Subject | [PATCH] sched/fair: Fix detection of per-CPU kthreads waking a task | Date | Wed, 24 Nov 2021 15:42:39 +0000 |
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select_idle_sibling() will return prev_cpu for the case where the task is woken up by a per-CPU kthread. However, the idle task has been recently modified and is now identified by is_per_cpu_kthread(), breaking the behaviour described above. Using !is_idle_task() ensures we do not spuriously trigger that select_idle_sibling() exit path.
Fixes: 00b89fe0197f ("sched: Make the idle task quack like a per-CPU kthread") Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 945d987246c5..8bf95b0e368d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6399,6 +6399,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) * pattern is IO completions. */ if (is_per_cpu_kthread(current) && + !is_idle_task(current) && prev == smp_processor_id() && this_rq()->nr_running <= 1) { return prev; -- 2.25.1
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