From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] revoke: misc fixes
Date: Mon, 19 Mar 2007 16:37:13 +1100 [thread overview]
Message-ID: <45FE2189.80709@yahoo.com.au> (raw)
In-Reply-To: <84144f020703160152h61439b28i9e438238567a4ba0@mail.gmail.com>
Pekka Enberg wrote:
> On 3/16/07, Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
>> Also, a down_write_trylock attempt inside i_mmap_lock should be a valid
>> optimisation.
>
>
> I am not sure what you're thinking here. down_write_trylock acquires
> ->mmap_sem which can deadlock with ->i_mmap_lock, no?
You need hold and wait for a deadlock. So long as you don't block
(on mmap_sem) while holding i_mmap_lock, then you won't deadlock.
So you could just attempt a trylock, and if it works, then you
could revoke the vma right then and there. OTOH, the patch you
subsequently posted looks fine, so unless this is performance
critical then I wouldn't bother ;)
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2007-03-19 5:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-16 7:17 [PATCH 1/3] revoke: misc fixes Pekka J Enberg
2007-03-16 7:21 ` Nick Piggin
2007-03-16 7:29 ` Pekka J Enberg
2007-03-16 7:38 ` Nick Piggin
2007-03-16 7:45 ` Pekka J Enberg
2007-03-16 7:50 ` Nick Piggin
2007-03-16 7:51 ` Pekka J Enberg
2007-03-16 8:52 ` Pekka Enberg
2007-03-19 5:37 ` Nick Piggin [this message]
2007-03-19 6:59 ` Pekka J Enberg
-- strict thread matches above, loose matches on Subject: below --
2007-03-16 9:47 Pekka J Enberg
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