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To: Jesper Juhl <juhl-lkml@dif.dk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Linux 2.6.0-test8 __might_sleep warnings on boot
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From: Roland Dreier <roland@digitalvampire.org>
Date: 19 Oct 2003 12:17:23 -0700
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>>>>> " " == Jesper Juhl <juhl-lkml@dif.dk> writes:

    > On Sun, 18 Oct 2003, Roland Dreier wrote:
    > 
    > > -	if (in_atomic() || irqs_disabled()) {
    > > +	/* Don't print warnings until system_running is set.  This avoids
    > > +	   spurious warnings during boot before local_irq_enable() and
    > > +	   init_idle(). */
    > > +	if (system_running && (in_atomic() || irqs_disabled())) {
    > 
    > Wouldn't this :
    > 
    > if ((in_atomic() || irqs_disabled()) && system_running)
    > 
    > be slightly more efficient?   The reason I say that is that I would assume
    > that the chance of (in_atomic() || irqs_disabled()) being false is greater
    > than the chance of !system_running - if that is so, then reordering the if
    > will allow it to break out early more often...

Yes, I think you're right about the efficiency.  However, I didn't
think this was a performance-critical code path (especially since it
is only turned on by a debugging config option), and the way I wrote
it matched the way I was thinking about the test ("If the system is
running, then check if we're in atomic or have irqs disabled").
But I don't think it matters much either way.

Thanks,
  Roland