From 8bf21433f38b020c3d8a3805d1d7fb73d7b40c01 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Wed, 14 May 2014 11:40:37 -0400 Subject: [PATCH] sched: Call select_idle_sibling() when not affine_sd On smaller systems, the top level sched domain will be an affine domain, and select_idle_sibling is invoked for every SD_WAKE_AFFINE wakeup. This seems to be working well. On larger systems, with the node distance between far away NUMA nodes being > RECLAIM_DISTANCE, select_idle_sibling is only called if the waker and the wakee are on nodes less than RECLAIM_DISTANCE apart. This patch leaves in place the policy of not pulling the task across nodes on such systems, while fixing the issue that select_idle_sibling is not called at all in certain circumstances. The code will look for an idle CPU in the same CPU package as the CPU where the task ran previously. Signed-off-by: Rik van Riel Signed-off-by: Peter Zijlstra Cc: morten.rasmussen@arm.com Cc: george.mccollister@gmail.com Cc: ktkhai@parallels.com Cc: Mel Gorman Cc: Mike Galbraith Link: http://lkml.kernel.org/r/20140514114037.2d93266f@annuminas.surriel.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index dd3fa14a2998..429164d117ea 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4473,10 +4473,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f sd = tmp; } - if (affine_sd) { - if (cpu != prev_cpu && wake_affine(affine_sd, p, sync)) - prev_cpu = cpu; + if (affine_sd && cpu != prev_cpu && wake_affine(affine_sd, p, sync)) + prev_cpu = cpu; + if (sd_flag & SD_BALANCE_WAKE) { new_cpu = select_idle_sibling(p, prev_cpu); goto unlock; } -- 2.20.1