From: Herbert Xu <[EMAIL PROTECTED]>
Date: Sun, 18 Nov 2007 10:07:37 +0800
> On Sat, Nov 17, 2007 at 04:45:42PM -0800, David Miller wrote:
> >
> > Herbert, you asked about just nop'ing out cond_resched() when we're
> > doing real preemption.
> >
> > A lot of code goes:
> >
> > if (need_resched()) {
> > /* drop some locks, etc. */
> > cond_resched();
> > /* reacquire locks, etc. */
> > }
> >
> > So it has to do something even with real preemption enabled.
>
> Actually that shouldn't be necessary. Because things like spin_unlock
> does preempt_enable which in turn does:
>
> #define preempt_enable() \
> do { \
> preempt_enable_no_resched(); \
> barrier(); \
> preempt_check_resched(); \
> } while (0)
>
> when CONFIG_PREEMPT is enabled. So at least in this case the
> cond_resched call is superfluous.
I see what you mean, ok yes that would catch it.
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