Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT
From: Steven Rostedt
Date: Tue Sep 29 2015 - 11:01:03 EST
[ Resend, with the Cc list back ]
On Tue, 29 Sep 2015 16:35:59 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Tue, Sep 29, 2015 at 10:37:29AM -0400, Steven Rostedt wrote:
> > On Tue, 29 Sep 2015 11:28:26 +0200
> > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > > As per commit d86ee4809d03 ("sched: optimize cond_resched()") we need
> > > PREEMPT_ACTIVE to avoid cond_resched() from working before the
> > > scheduler is setup.
> > >
> > > However, keeping preemption disabled should do the same thing already,
> > > making the PREEMPT_ACTIVE part entirely redundant.
> > Thus PREEMPT_ACTIVE wasn't needed at that commit either, or was it?
> Correct. We might have actually discussed that at that time but decided
> to be conservative -- but these be vague memories..
Hmm, I just looked closer and I'm wondering if this still works?
#define PREEMPT_DISABLED (1 + PREEMPT_ENABLED)
#define PREEMPT_DISABLED PREEMPT_ENABLED
Now if we just remove the PREEMPT_ACTIVE from the INIT_PREEMPT_COUNT,
when CONFIG_PREEMPT_COUNT is not set, wouldn't a _cond_resched() in
boot up schedule?
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