Messages in this thread Patch in this message | | | Date | Mon, 16 May 2011 10:37:53 GMT | From | tip-bot for Yong Zhang <> | Subject | [tip:sched/core] sched: Avoid going ahead if ->cpus_allowed is not changed |
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Commit-ID: db44fc017d5989302713ab4e7f9e922b648f4b59 Gitweb: http://git.kernel.org/tip/db44fc017d5989302713ab4e7f9e922b648f4b59 Author: Yong Zhang <yong.zhang0@gmail.com> AuthorDate: Mon, 9 May 2011 22:07:05 +0800 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Mon, 16 May 2011 11:01:18 +0200
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> --- kernel/sched.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index b8b9a7d..70bec4f 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; }
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