From: Gautham R. Shenoy Date: Tue, 11 May 2021 15:16:09 +0000 (+0530) Subject: sched/fair: Fix clearing of has_idle_cores flag in select_idle_cpu() X-Git-Tag: v5.12.5~62 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ead8ea54ecc465da19c4605b2d33874216155351;p=thirdparty%2Fkernel%2Fstable.git sched/fair: Fix clearing of has_idle_cores flag in select_idle_cpu() [ Upstream commit 02dbb7246c5bbbbe1607ebdc546ba5c454a664b1 ] In commit: 9fe1f127b913 ("sched/fair: Merge select_idle_core/cpu()") in select_idle_cpu(), we check if an idle core is present in the LLC of the target CPU via the flag "has_idle_cores". We look for the idle core in select_idle_cores(). If select_idle_cores() isn't able to find an idle core/CPU, we need to unset the has_idle_cores flag in the LLC of the target to prevent other CPUs from going down this route. However, the current code is unsetting it in the LLC of the current CPU instead of the target CPU. This patch fixes this issue. Fixes: 9fe1f127b913 ("sched/fair: Merge select_idle_core/cpu()") Signed-off-by: Gautham R. Shenoy Signed-off-by: Ingo Molnar Reviewed-by: Vincent Guittot Reviewed-by: Srikar Dronamraju Acked-by: Mel Gorman Link: https://lore.kernel.org/r/1620746169-13996-1-git-send-email-ego@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index edcabae5c658b..a073a839cd065 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6212,7 +6212,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool } if (has_idle_core) - set_idle_cores(this, false); + set_idle_cores(target, false); if (sched_feat(SIS_PROP) && !has_idle_core) { time = cpu_clock(this) - time;