On Wed, May 14, 2014 at 11:40:37AM -0400, Rik van Riel wrote: > Subject: 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 <[email protected]> > --- > 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 39b63d0..1e58159 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4423,10 +4423,10 @@ 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_WAKE_AFFINE) {
I think you meant SD_BALANCE_WAKE? > new_cpu = select_idle_sibling(p, prev_cpu); > goto unlock; > }
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