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authorRik van Riel <riel@redhat.com>2017-06-23 12:55:28 -0400
committerIngo Molnar <mingo@kernel.org>2017-06-24 08:57:52 +0200
commit7d894e6e34a5cdd12309c7e4a3f830277ad4b7bf (patch)
tree39d5fea658872e904ce00e208851a9f204545d3f /kernel
parent739294fb03f590401bbd7faa6d31a507e3ffada5 (diff)
downloadlinux-7d894e6e34a5cdd12309c7e4a3f830277ad4b7bf.tar.bz2
sched/fair: Simplify wake_affine() for the single socket case
Then 'this_cpu' and 'prev_cpu' are in the same socket, select_idle_sibling() will do its thing regardless of the return value of wake_affine(). Just return true and don't look at all the other things. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jhladky@redhat.com Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20170623165530.22514-3-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/fair.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6e0c0524131e..fe1901686fa5 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5420,6 +5420,13 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
this_load = target_load(this_cpu, idx);
/*
+ * Common case: CPUs are in the same socket, and select_idle_sibling()
+ * will do its thing regardless of what we return:
+ */
+ if (cpus_share_cache(prev_cpu, this_cpu))
+ return true;
+
+ /*
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
* of the current CPU:
@@ -6007,11 +6014,15 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (affine_sd) {
sd = NULL; /* Prefer wake_affine over balance flags */
- if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
+ if (cpu == prev_cpu)
+ goto pick_cpu;
+
+ if (wake_affine(affine_sd, p, prev_cpu, sync))
new_cpu = cpu;
}
if (!sd) {
+ pick_cpu:
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);