From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: mc@linux.vnet.ibm.com
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
Stephen Boyd <sboyd@codeaurora.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Nick Piggin <npiggin@kernel.dk>,
david@fromorbit.com,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
Maciej Rutecki <maciej.rutecki@gmail.com>
Subject: Re: [PATCH] VFS: br_write_lock locks on possible CPUs other than online CPUs
Date: Tue, 20 Dec 2011 13:07:44 +0530 [thread overview]
Message-ID: <4EF03B48.6000006@linux.vnet.ibm.com> (raw)
In-Reply-To: <1324366218.21588.5.camel@mengcong>
On 12/20/2011 01:00 PM, mengcong wrote:
> On Tue, 2011-12-20 at 06:27 +0000, Al Viro wrote:
>> On Tue, Dec 20, 2011 at 10:26:05AM +0530, Srivatsa S. Bhat wrote:
>>> Oh, right, that has to be handled as well...
>>>
>>> Hmmm... How about registering a CPU hotplug notifier callback during lock init
>>> time, and then for every cpu that gets onlined (after we took a copy of the
>>> cpu_online_mask to work with), we see if that cpu is different from the ones
>>> we have already locked, and if it is, we lock it in the callback handler and
>>> update the locked_cpu_mask appropriately (so that we release the locks properly
>>> during the unlock operation).
>>>
>>> Handling the newly introduced race between the callback handler and lock-unlock
>>> code must not be difficult, I believe..
>>>
>>> Any loopholes in this approach? Or is the additional complexity just not worth
>>> it here?
>>
>> To summarize the modified variant of that approach hashed out on IRC:
>>
> On which IRC do you discuss?
#kernel on tinc.sekrit.org :-)
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2011-12-20 7:37 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-19 3:36 [PATCH] VFS: br_write_lock locks on possible CPUs other than online CPUs mengcong
2011-12-19 4:11 ` Al Viro
2011-12-19 5:00 ` Dave Chinner
2011-12-19 6:07 ` mengcong
2011-12-19 7:31 ` Srivatsa S. Bhat
2011-12-19 9:12 ` Stephen Boyd
2011-12-19 11:03 ` Srivatsa S. Bhat
2011-12-19 12:11 ` Al Viro
2011-12-19 20:23 ` Srivatsa S. Bhat
2011-12-19 20:52 ` Al Viro
2011-12-20 4:56 ` Srivatsa S. Bhat
2011-12-20 6:27 ` Al Viro
2011-12-20 7:28 ` Srivatsa S. Bhat
2011-12-20 9:37 ` mengcong
2011-12-20 10:36 ` Srivatsa S. Bhat
2011-12-20 11:08 ` Srivatsa S. Bhat
2011-12-20 12:50 ` Srivatsa S. Bhat
2011-12-20 14:06 ` Al Viro
2011-12-20 14:35 ` Srivatsa S. Bhat
2011-12-20 17:59 ` Al Viro
2011-12-20 19:12 ` Srivatsa S. Bhat
2011-12-20 19:58 ` Al Viro
2011-12-20 22:27 ` Dave Chinner
2011-12-20 23:31 ` Al Viro
2011-12-21 21:15 ` Srivatsa S. Bhat
2011-12-21 22:02 ` Al Viro
2011-12-21 22:12 ` Andrew Morton
2011-12-22 7:02 ` Al Viro
2011-12-22 7:20 ` Andrew Morton
2011-12-22 8:08 ` Al Viro
2011-12-22 8:17 ` Andi Kleen
2011-12-22 8:39 ` Al Viro
2011-12-22 8:22 ` Andi Kleen
2011-12-20 7:30 ` mengcong
2011-12-20 7:37 ` Srivatsa S. Bhat [this message]
2011-12-19 23:56 ` Dave Chinner
2011-12-20 4:05 ` Al Viro
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