Messages in this thread | | | From | Vincent Guittot <> | Date | Tue, 27 Apr 2021 09:08:44 +0200 | Subject | Re: [PATCH] sched/fair: Fix unsetting of "has_idle_cores" flag |
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On Mon, 26 Apr 2021 at 19:04, Gautham R. Shenoy <ego@linux.vnet.ibm.com> wrote: > > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > 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: Commit 9fe1f127b913 ("sched/fair: Merge select_idle_core/cpu()") > Cc: Mel Gorman <mgorman@techsingularity.net> > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> --- > kernel/sched/fair.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 794c2cb..5fb5020 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6171,7 +6171,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t > } > > if (smt) > - set_idle_cores(this, false); > + set_idle_cores(target, false); > > if (sched_feat(SIS_PROP) && !smt) { > time = cpu_clock(this) - time; > -- > 1.9.4 >
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