From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>
Subject: Re: Problem with cpu_rest() change
Date: Wed, 26 Jan 2005 10:49:12 +1100 [thread overview]
Message-ID: <1106696952.6244.22.camel@gaston> (raw)
In-Reply-To: <20050125090131.GA4986@elte.hu>
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.
next prev parent reply other threads:[~2005-01-25 23:54 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 [this message]
2005-01-26 5:45 ` Kumar Gala
2005-01-26 13:44 ` Benjamin Herrenschmidt
2005-01-26 14:10 ` Kumar Gala
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