lkml.org 
[lkml]   [2016]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [bisected] "sched: Allow per-cpu kernel threads to run on online && !active" causes warning
On Wed, Jul 27, 2016 at 05:23:05PM +0200, Thomas Gleixner wrote:
> On Wed, 27 Jul 2016, Heiko Carstens wrote:
> > [ 3.162961] ([<0000000000176c30>] select_task_rq+0xc0/0x1a8)
> > [ 3.162963] ([<0000000000177d64>] try_to_wake_up+0x2e4/0x478)
> > [ 3.162968] ([<000000000015d46c>] create_worker+0x174/0x1c0)
> > [ 3.162971] ([<0000000000161a98>] alloc_unbound_pwq+0x360/0x438)
>
> > For some unknown reason select_task_rq() gets called with a task that has
> > nr_cpus_allowed == 0. Hence "cpu = cpumask_any(tsk_cpus_allowed(p));"
> > within select_task_rq() will set cpu to nr_cpu_ids which in turn causes the
> > warning later on.
> >
> > It only happens with more than one node, otherwise it seems to work fine.
> >
> > Any idea what could be wrong here?
>
> create_worker()
> tsk = kthread_create_on_node();
> kthread_bind_mask(tsk, pool->attrs->cpumask);
> do_set_cpus_allowed(tsk, mask);
> set_cpus_allowed_common(tsk, mask);
> cpumask_copy(&tsk->cpus_allowed, mask);
> tsk->nr_cpus_allowed = cpumask_weight(mask);
> wake_up_process(task);
>
> So this looks like pool->attrs->cpumask is simply empty.....

Just had some time to look into this a bit more. Looks like we initialize
the cpu_to_node_masks (way) too late on s390 for fake numa. So Peter's
patch just revealed that problem.

I'll see if initializing the masks earlier will fix this, but I think it
will.

\
 
 \ /
  Last update: 2016-07-30 14:01    [W:0.069 / U:0.328 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site