From: Kumar Gala <kumar.gala@freescale.com>
To: "Benjamin Herrenschmidt" <benh@kernel.crashing.org>
Cc: "Linux Kernel list" <linux-kernel@vger.kernel.org>,
"Andrew Morton" <akpm@osdl.org>, "Ingo Molnar" <mingo@elte.hu>
Subject: Re: Problem with cpu_rest() change
Date: Tue, 25 Jan 2005 23:45:33 -0600 [thread overview]
Message-ID: <7E912176-6F5D-11D9-986F-000393DBC2E8@freescale.com> (raw)
In-Reply-To: <1106696952.6244.22.camel@gaston>
Will these changes cause us to back out the patch already made to
arch/ppc/kernel/idle.c for systems that did not support powersavings?
- kumar
On Jan 25, 2005, at 5:49 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2005-01-25 at 10:01 +0100, Ingo Molnar wrote:
>
> > it can be bad for the idle task to hold the BKL and to have
> preemption
> > enabled - in such a situation the scheduler will get confused if an
> > interrupt triggers a forced preemption in that small window. But
> it's
> > not necessary to keep IRQs disabled after the BKL has been dropped.
> In
> > fact i think IRQ-disabling doesnt have to be done at all, the patch
> > below ought to solve this scenario equally well, and should solve
> the
> > PPC side-effects too.
> >
> > Tested ontop of 2.6.11-rc2 on x86 PREEMPT+SMP and PREEMPT+!SMP (which
> > IIRC were the config variants that triggered the original problem),
> on
> > an SMP and on a UP system.
>
> Excellent, thanks.
>
> Ben.
>
>
>
> -
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next prev parent reply other threads:[~2005-01-26 5:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-24 2:40 Problem with cpu_rest() change Benjamin Herrenschmidt
2005-01-25 9:01 ` Ingo Molnar
2005-01-25 23:49 ` Benjamin Herrenschmidt
2005-01-26 5:45 ` Kumar Gala [this message]
2005-01-26 13:44 ` Benjamin Herrenschmidt
2005-01-26 14:10 ` Kumar Gala
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