lkml.org 
[lkml]   [2015]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 0/6] stop_machine: kill stop_cpus_mutex and stop_cpus_lock
On 06/29, Peter Zijlstra wrote:
>
> On Mon, Jun 29, 2015 at 06:02:51AM +0200, Oleg Nesterov wrote:
>
> > If we change stop_two_cpus() to use stop_work_alloc_one() it can use
> > cpu_online(),
>
> So the one user of this actually needs cpu_active(); we do not want to
> go move tasks to an inactive cpu.
>
> So if you change this to cpu_online() we need to audit the user is doing
> the stricter test.

Hmm. But the user (migrate_swap_stop) should check cpu_active() anyway?

The cpu_active() checks in stop_two_cpus() can only help to ensure that
multi_cpu_stop() won't hang. CPU_DOWN_PREPARE can deactivate either CPU
right after the check?

Or stop_two_cpus() needs get_online_cpus(). Or I missed something.

Oleg.



\
 
 \ /
  Last update: 2015-06-30 03:21    [W:0.061 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site