lkml.org 
[lkml]   [2012]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/4] cputime: Consolidate vtime handling on context switch
On Wed, Aug 15, 2012 at 05:22:19PM +0200, Martin Schwidefsky wrote:
> On Tue, 14 Aug 2012 16:16:49 +0200
> Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
> > The archs that implement virtual cputime accounting all
> > flush the cputime of a task when it gets descheduled
> > and sometimes set up some ground initialization for the
> > next task to account its cputime.
> >
> > These archs all put their own hooks in their context
> > switch callbacks and handle the off-case themselves.
> >
> > Consolidate this by creating a new account_switch_vtime()
> > callback called in generic code right after a context switch
> > and that these archs must implement to flush the prev task
> > cputime and initialize the next task cputime related state.
>
> That change requires that the accounting for the previous process
> can be done before finish_arch_switch() completed. With the old
> code the architecture could to the accounting call in the middle
> of finish_arch_switch, that is not possible anymore. Dunno if this
> is relevant or not. For s390 the new code should work fine.

I'm not sure how this could potentially cause a problem. Interrupts are disabled
between while we switch_to() until finish_lock_switch(). So nothing
should be able to mess up with the accounting of the prev task.

I don't really understand what you mean actually.

Thanks.


\
 
 \ /
  Last update: 2012-08-15 22:02    [W:0.068 / U:0.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site