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From: Paul Jackson <pj@sgi.com>
To: balbir@in.ibm.com
Cc: vatsa@in.ibm.com, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix race between attach_task and cpuset_exit
Date: Sun, 25 Mar 2007 12:54:03 -0700	[thread overview]
Message-ID: <20070325125403.3749b45c.pj@sgi.com> (raw)
In-Reply-To: <4606B6CF.6040306@in.ibm.com>

> How about using a local variable like ref_count and using
> 
> ref_count = atomic_dec_and_test(&cs->count); This will avoid the two
> atomic operations, atomic_dec() and atomic_read() below.

This would also seem to address the race I just noticed in my previous
reply.

Though I would suggest that we use the same code pattern in both
cpuset_exit and attach_task -- either both use cpuset_to_be_released,
or both use ref_count.

I tend to prefer the cpuset_to_be_released form - seems a bit more
explicitly clear to me.  But vatsa's doing the patch - he gets the
last vote.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

  reply	other threads:[~2007-03-25 19:54 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-25 16:47 [PATCH] Fix race between attach_task and cpuset_exit Srivatsa Vaddagiri
2007-03-25 17:52 ` Balbir Singh
2007-03-25 19:54   ` Paul Jackson [this message]
2007-03-26 11:50   ` Srivatsa Vaddagiri
2007-03-26 17:58     ` Paul Jackson
2007-03-27  6:35       ` Srivatsa Vaddagiri
2007-03-27  8:45         ` Paul Jackson
2007-03-26 18:30     ` Paul Jackson
2007-03-25 19:50 ` Paul Jackson
2007-03-26 11:55   ` Srivatsa Vaddagiri
2007-04-05  5:55     ` Paul Menage
2007-04-05  7:00       ` Srivatsa Vaddagiri
2007-04-05  7:01         ` Paul Menage
2007-04-05  8:14           ` Srivatsa Vaddagiri
2007-04-05  8:10             ` Paul Menage
2007-04-10 17:12       ` Srivatsa Vaddagiri

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