Commit db44fc01 authored May 09, 2011 by Yong Zhang Committed by Ingo Molnar May 16, 2011

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 <yong.zhang0@gmail.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110509140705.GA2219@zhy


Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 61eadef6

kernel/sched.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}