[lkml]   [2011]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] sched: correct how RT task is picked
On Wed, May 18, 2011 at 9:38 AM, Steven Rostedt <> wrote:
>> I think you can take a look at next_prio(), it just calculate the
>> next highest task on the current cpu; in this case,
>> cpumask_test_cpu(cpu, &p->cpus_allowed) will be true for the most
>> of time, but maybe that task is bound to this cpu.
> I've been looking at the history here, and I think that '-1' is a relic.
> If you look at sched_rt.c in f65eda4f789168ba5ff3fa75546c29efeed19f58:
> $ git show f65eda4f:kernel/sched_rt.c
> You'll see that push_rt_task calls pick_next_highest_task_rt() with a
> -1. That code has long been replaced.

Yeah, the condition "cpu < 0" could be removed since we have no
that kind of caller.

> I'm a bit nervous about taking Hillf's patch as is. But a little more
> reviewing and testing may prove that it is legit.

But another point is like I said before:
'cpumask_test_cpu(cpu, &p->cpus_allowed)' doesn't equal to
'p->rt.nr_cpus_allowed > 1' because we could have bounded
So the condition 'if (cpumask_test_cpu(cpu, &p->cpus_allowed))'
in Hillf's patch is not sufficient.


Only stand for myself

 \ /
  Last update: 2011-05-18 04:35    [W:0.091 / U:0.268 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site