From db44fc017d5989302713ab4e7f9e922b648f4b59 Mon Sep 17 00:00:00 2001 From: Yong Zhang Date: Mon, 9 May 2011 22:07:05 +0800 Subject: [PATCH] sched: Avoid going ahead if ->cpus_allowed is not changed If cpumask_equal(&p->cpus_allowed, new_mask) is true, seems there is no reason to prevent set_cpus_allowed_ptr() return directly. Signed-off-by: Yong Zhang Acked-by: Hillf Danton Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110509140705.GA2219@zhy Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index b8b9a7dac9b0..70bec4f1edbb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5946,13 +5946,15 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) rq = task_rq_lock(p, &flags); + if (cpumask_equal(&p->cpus_allowed, new_mask)) + goto out; + if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; goto out; } - if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && - !cpumask_equal(&p->cpus_allowed, new_mask))) { + if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { ret = -EINVAL; goto out; } -- GitLab