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: Ubuntu-5.15.0-36.37~448 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=088736b6a935956f3f4dd9d3acb1f87142bdfb3c;p=mirror_ubuntu-jammy-kernel.git sched: Teach the forced-newidle balancer about CPU affinity limitation. BugLink: https://bugs.launchpad.net/bugs/1969107 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 (cherry picked from commit ff6505766565616deb65a203e62d4ca63c6c277b) Signed-off-by: Paolo Pisati --- diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 07515cef38fb..2abefdb511b2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5927,7 +5927,7 @@ 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)