From: Andrew Morton <akpm@digeo.com>
To: Robert Love <rml@tech9.net>
Cc: Dave Hansen <haveblue@us.ibm.com>,
lkml <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: 2.5.40-mm2
Date: Sun, 06 Oct 2002 15:33:23 -0700 [thread overview]
Message-ID: <3DA0BA33.5B295A46@digeo.com> (raw)
In-Reply-To: 1033943021.27093.29.camel@phantasy
Robert Love wrote:
>
> On Sun, 2002-10-06 at 18:07, Andrew Morton wrote:
>
> > > - while (base->running_timer == timer) {
> > > + while (base->running_timer == timer)
> > > cpu_relax();
> > > - preempt_disable();
> > > - preempt_enable();
>
> I am confused as to why Ingo would put these here. He knows very well
> what he is doing... surely he had a reason.
>
> If he intended to force a preemption point here, then the lines needs to
> be reversed. This assumes, of course, preemption is disabled here. But
> I do not think it is.
>
> If he just wanted to check for preemption, we have a
> preempt_check_resched() which does just that (I even think he wrote
> it). Note as long as interrupts are enabled this probably does not
> achieve much anyhow.
>
I think it's a way of doing "cond_resched() if cond_resched() is
a legal thing to do right now".
I'm sure David isn't using preempt though.
next prev parent reply other threads:[~2002-10-06 22:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-06 18:47 2.5.40-mm2 Andrew Morton
2002-10-06 20:47 ` 2.5.40-mm2 Dave Hansen
2002-10-06 21:55 ` 2.5.40-mm2 Andrew Morton
2002-10-06 22:07 ` 2.5.40-mm2 Andrew Morton
2002-10-06 22:11 ` 2.5.40-mm2 Andrew Morton
2002-10-07 5:46 ` 2.5.40-mm2 Dave Hansen
2002-10-06 22:23 ` 2.5.40-mm2 Robert Love
2002-10-06 22:33 ` Andrew Morton [this message]
2002-10-06 22:38 ` 2.5.40-mm2 Robert Love
2002-10-08 11:05 ` 2.5.40-mm2 Ingo Molnar
2002-10-08 16:23 ` 2.5.40-mm2 Dave Hansen
2002-10-08 16:43 ` 2.5.40-mm2 Dave Hansen
2002-10-08 16:56 ` 2.5.40-mm2 Andrew Morton
2002-10-09 8:12 ` 2.5.40-mm2 Ingo Molnar
2002-10-07 17:45 ` 2.5.40-mm2 Badari Pulavarty
2002-10-07 17:55 ` 2.5.40-mm2 Jens Axboe
2002-10-07 18:23 ` 2.5.40-mm2 Andrew Morton
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