diff options
| author | Xunlei Pang <pang.xunlei@linaro.org> | 2015-01-19 04:49:37 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-02-04 07:52:29 +0100 |
| commit | 9659e1eeee28f7025b6545934d644d19e9c6e603 (patch) | |
| tree | 3bb75071a8e934f87e95e3fc7006e250257f9358 /kernel | |
| parent | 868933359a3bdda25b562e9d41bce7071edc1b08 (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')
| -rw-r--r-- | kernel/sched/cpudeadline.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c index fd9d3fb49d0..c6acb07466b 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) && |