From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Andrew Morton <akpm@linux-foundation.org>, paulmck@linux.vnet.ibm.com
Cc: ego@in.ibm.com, rusty@rustcorp.com.au, mingo@elte.hu,
linux-kernel@vger.kernel.org, peterz@infradead.org,
oleg@redhat.com, dipankar@in.ibm.com
Subject: Re: [PATCH -mm resend] cpuhotplug: introduce try_get_online_cpus() take 3
Date: Thu, 11 Jun 2009 16:41:42 +0800 [thread overview]
Message-ID: <4A30C346.8070406@cn.fujitsu.com> (raw)
In-Reply-To: <20090609184238.06b38c3e.akpm@linux-foundation.org>
Andrew Morton wrote:
>
> I still think we should really avoid having to do this. trylocks are
> nasty things.
>
> Looking at the above, one would think that a correct fix would be to fix
> the bug in "thread 2": take the locks in the correct order? As
> try_get_online_cpus() doesn't actually have any callers, it's hard to
> take that thought any further.
>
>
Sometimes, we can not reorder the locks' order.
try_get_online_cpus() is really needless when no one uses it.
Paul's expedited RCU V7 may need it:
http://lkml.org/lkml/2009/5/22/332
So this patch can be omitted when Paul does not use it.
It's totally OK for me.
Lai
next prev parent reply other threads:[~2009-06-11 8:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-29 8:29 [PATCH 1/2] cpuhotplug: use rw_semaphore for cpu_hotplug Lai Jiangshan
2009-05-29 20:23 ` Andrew Morton
2009-05-29 21:07 ` Oleg Nesterov
2009-05-29 21:17 ` Oleg Nesterov
2009-06-01 1:04 ` Lai Jiangshan
2009-06-01 0:52 ` Lai Jiangshan
2009-06-01 2:22 ` Lai Jiangshan
2009-05-30 1:53 ` Paul E. McKenney
2009-05-30 4:37 ` Gautham R Shenoy
2009-06-04 6:58 ` [PATCH] cpuhotplug: introduce try_get_online_cpus() take 2 Lai Jiangshan
2009-06-04 20:49 ` Oleg Nesterov
2009-06-05 1:32 ` Lai Jiangshan
2009-06-05 2:14 ` Oleg Nesterov
2009-06-05 15:37 ` Paul E. McKenney
2009-06-08 2:36 ` Lai Jiangshan
2009-06-08 4:19 ` Gautham R Shenoy
2009-06-08 14:25 ` Paul E. McKenney
2009-06-09 12:07 ` [PATCH -mm] cpuhotplug: introduce try_get_online_cpus() take 3 Lai Jiangshan
2009-06-09 19:34 ` Andrew Morton
2009-06-09 23:47 ` Paul E. McKenney
2009-06-10 1:13 ` [PATCH -mm resend] " Lai Jiangshan
2009-06-10 1:42 ` Andrew Morton
2009-06-11 8:41 ` Lai Jiangshan [this message]
2009-06-11 18:50 ` Paul E. McKenney
2009-06-15 4:04 ` Gautham R Shenoy
2009-06-10 0:57 ` [PATCH -mm] " Lai Jiangshan
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