Message-ID: <42892447.5000304@yahoo.com.au>
Date: Tue, 17 May 2005 08:52:55 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.6) Gecko/20050324 Debian/1.7.6-1
MIME-Version: 1.0
To: Oleg Nesterov <oleg@tv-sign.ru>
CC: linux-kernel@vger.kernel.org
Subject: Re: [patch] improve SMP reschedule and idle routines
References: <4288A55B.10F7240E@tv-sign.ru>
In-Reply-To: <4288A55B.10F7240E@tv-sign.ru>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1015
Lines: 36

Oleg Nesterov wrote:
> Nick Piggin wrote:
> 
>> void default_idle(void)
>> {
>>+	local_irq_enable();
>>+
> 
> 
> Stupid question. Why is this sti() needed?
> 
> Interrupts are enabled in start_secondary() before cpu_idle()
> call, and they can't be disabled after return from schedule().
> 
> The same question applies to poll_idle/mwait_idle.
> 

IIRC I tried to do that, but I think I ran into problems with
acpi_processor_idle which looks like it can call the cpu idle
routines with interrupts disabled. I definitely ran into problems
with something.

That should really be cleaned up though (whether we go one way
or the other doesn't matter as much as it being consistent),
I think.

But I wanted to try to keep this patch to a minimum.

-- 
SUSE Labs, Novell Inc.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/