Re: [PATCH v2] sched/fair: Fix clearing of has_idle_cores flag

[Peter Zijlstra]

On Tue, May 11, 2021 at 08:46:09PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@xxxxxxxxxxxxxxxxxx>
> 
> 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()")
> Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>

Thanks!