Messages in this thread | | | Date | Wed, 15 Aug 2012 21:28:17 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 3/4] cputime: Consolidate vtime handling on context switch |
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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.
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