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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: unlisted-recipients:; (no To-header on input)
Cc: Dave Hansen <haveblue@us.ibm.com>,
	"Matthew C. Dobson [imap]" <colpatch@us.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: sched domains bringup race?
Date: Fri, 16 Jul 2004 15:27:59 +1000	[thread overview]
Message-ID: <40F7675F.6090506@yahoo.com.au> (raw)
In-Reply-To: <40F74F9C.8080205@yahoo.com.au>

Nick Piggin wrote:
> Dave Hansen wrote:
> 
>> On Thu, 2004-07-15 at 20:03, Nick Piggin wrote:
>>
>>> It shouldn't because sched_init sets up dummy domains for
>>> all runqueues.
>>>
>>> Obviously something is going wrong somewhere though.
>>
>>
>>
>> Hmmm, but there still might be some concurrency problems, right?  There
>> isn't any locking while the setup is being done, so are all of the
>> intermediate initialization states valid?  Or, could one of the CPUs be
>> catching the init code in the middle of an operation?
>>
> 
> cpu_attach_domain is supposed to be able to do the switchover
> without any races.

Although the sched_domain_debug is definitely racy. It should really
be locking each runqueue before traversing its domains. Just undef
SCHED_DOMAIN_DEBUG to be sure...

  reply	other threads:[~2004-07-16  5:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-16  2:13 sched domains bringup race? Dave Hansen
2004-07-16  3:03 ` Nick Piggin
2004-07-16  3:30   ` Dave Hansen
2004-07-16  3:46     ` Nick Piggin
2004-07-16  5:27       ` Nick Piggin [this message]
2004-07-18 20:45 ` Keshavamurthy Anil S
2004-07-19  7:31   ` Nick Piggin
2004-07-22 21:55     ` Nathan Lynch
2004-07-22 23:23       ` Keshavamurthy Anil S
2004-07-23  0:33       ` Nick Piggin

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