Messages in this thread Patch in this message | | | Date | Fri, 18 Sep 2015 09:52:15 +0200 | From | Peter Zijlstra <> | Subject | Re: single_task_running() vs. preemption warnings (was Re: [PATCH] kvm: fix preemption warnings in kvm_vcpu_block) |
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On Thu, Sep 17, 2015 at 01:32:55PM -0700, Tim Chen wrote: > I have no objection to change single_task_running to use > raw_smp_processor_id. The worker in mcryptd is bound to > the cpu so it has no migration/preemption issue. So it shouldn't care > which smp_processor_id version is being used. Yes, please add a comment > to alert the user of this caveat should you change single_task_running.
We actually have raw_rq() for that, and the whole if thing looks rather superfluous. So something like the below, except with a suitable comment on and tested etc.. ;-)
--- kernel/sched/core.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6ab415aa15c4..f39c0498e284 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2666,10 +2666,7 @@ unsigned long nr_running(void) */ bool single_task_running(void) { - if (cpu_rq(smp_processor_id())->nr_running == 1) - return true; - else - return false; + return raw_rq()->nr_running == 1; } EXPORT_SYMBOL(single_task_running);
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