From: Sebastian Andrzej Siewior Date: Thu, 17 Mar 2022 14:51:32 +0000 (+0100) Subject: sched: Teach the forced-newidle balancer about CPU affinity limitation. X-Git-Tag: v5.16.20~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5181c4fa8ec154ac57de82f08b0aa5d21a9f100;p=thirdparty%2Fkernel%2Fstable.git sched: Teach the forced-newidle balancer about CPU affinity limitation. commit 386ef214c3c6ab111d05e1790e79475363abaa05 upstream. try_steal_cookie() looks at task_struct::cpus_mask to decide if the task could be moved to `this' CPU. It ignores that the task might be in a migration disabled section while not on the CPU. In this case the task must not be moved otherwise per-CPU assumption are broken. Use is_cpu_allowed(), as suggested by Peter Zijlstra, to decide if the a task can be moved. Fixes: d2dfa17bc7de6 ("sched: Trivial forced-newidle balancer") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/YjNK9El+3fzGmswf@linutronix.de Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0e4b8214af31c..4810503f79a57 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5889,7 +5889,7 @@ static bool try_steal_cookie(int this, int that) if (p == src->core_pick || p == src->curr) goto next; - if (!cpumask_test_cpu(this, &p->cpus_mask)) + if (!is_cpu_allowed(p, this)) goto next; if (p->core_occupation > dst->idle->core_occupation)