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authorXunlei Pang2015-01-19 04:49:37 +0000
committerIngo Molnar2015-02-04 07:52:29 +0100
commit9659e1eeee28f7025b6545934d644d19e9c6e603 (patch)
tree3bb75071a8e934f87e95e3fc7006e250257f9358 /kernel/sched
parent868933359a3bdda25b562e9d41bce7071edc1b08 (diff)
sched/deadline: Remove cpu_active_mask from cpudl_find()
cpu_active_mask is rarely changed (only on hotplug), so remove this operation to gain a little performance. If there is a change in cpu_active_mask, rq_online_dl() and rq_offline_dl() should take care of it normally, so cpudl::free_cpus carries enough information for us. For the rare case when a task is put onto a dying cpu (which rq_offline_dl() can't handle in a timely fashion), it will be handled through _cpu_down()->...->multi_cpu_stop()->migration_call() ->migrate_tasks(), preventing the task from hanging on the dead cpu. Cc: Juri Lelli <juri.lelli@gmail.com> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> [peterz: changelog] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1421642980-10045-2-git-send-email-pang.xunlei@linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/cpudeadline.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index fd9d3fb49d0d..c6acb07466bb 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -108,8 +108,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
const struct sched_dl_entity *dl_se = &p->dl;
if (later_mask &&
- cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed) &&
- cpumask_and(later_mask, later_mask, cpu_active_mask)) {
+ cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
best_cpu = cpumask_any(later_mask);
goto out;
} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&