Re: [PATCH/RFC] sched: Remove SYSTEM_RUNNING checks fromcond_resched*()

From: Anton Vorontsov
Date: Wed Jul 08 2009 - 17:33:40 EST


On Wed, Jul 08, 2009 at 02:10:24PM -0700, Andrew Morton wrote:
> > On Wed, 8 Jul 2009 09:12:30 -0700 (PDT) Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > That said, I do agree that maybe SYSTEM_RUNNING isn't the right check.
> > Testing that the scheduler is initialized may be the more correct one. I
> > think the SYSTEM_RUNNING one just comes from that being used for other
> > debug issues.
>
> Agreed. system_state is too general.
>
> If we specifically want to know whether it is safe to call schedule() then
> let's create a global boolean it_is_safe_to_call_schedule and test that,
> rather than testing something which indirectly and unreliably implies "it
> is safe to call schedule". If that boolean already exists then no-brainer.
>
> All that being said, I wonder if the netconsole code should be using
> msleep(1) instead. Spinning on cond_resched() is a bit rude. But one
> would have to verify that it is safe to call schedule() at this time, and
> for the netconsole caller, this is dubious.

What do you mean by "verify that it is safe"? If it works,
can I assume that it's safe? ;-) It works, fwiw.

Thanks,

--
Anton Vorontsov
email: cbouatmailru@xxxxxxxxx
irc://irc.freenode.net/bd2
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