lkml.org 
[lkml]   [2014]   [Mar]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] abort secondary CPU bring-up gracefully if do_boot_cpu timed out on cpu_callin_mask

* Igor Mammedov <imammedo@redhat.com> wrote:

> On Thu, 6 Mar 2014 08:08:32 +0100
> Ingo Molnar <mingo@kernel.org> wrote:
>
> >
> > * Igor Mammedov <imammedo@redhat.com> wrote:
> >
> > > Master CPU may timeout before cpu_callin_mask is set and cancel
> > > booting CPU, but being onlined CPU still continues to boot, sets
> > > cpu_active_mask (CPU_STARTING notifiers) and spins in
> > > check_tsc_sync_target() for master cpu to arrive. Following attempt
> > > to online another cpu hangs in stop_machine, initiated from here:
> >
> > The changelog needs to prominently contain a description of the
> > practical relevance of this patch: has the hang triggered on any
> > system and under what circumstances, and did the patch resolve the
> > hang, etc.?
>
> Hang is observed on virtual machines during CPU hotplug, especially
> in big guests with many CPUs. (It happens more often if host is
> over-committed).
>
> Similar patch is carried in RHEL6 since 2012 and it fixes issue
> there, when applied to upstream kernel it also fixes issue.

Okay, cool - please update the patch description with that and
resubmit.

Thanks,

Ingo


\
 
 \ /
  Last update: 2014-03-06 15:21    [W:0.052 / U:1.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site