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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
	hugh@veritas.com, linux-kernel@vger.kernel.org
Subject: Re: smp race fix between invalidate_inode_pages* and do_no_page
Date: Sun, 02 Apr 2006 15:17:44 +1000	[thread overview]
Message-ID: <442F5E78.9010905@yahoo.com.au> (raw)
In-Reply-To: <20060331123622.GB18093@opteron.random>

Hi Andrea, seems good to me.

Andrea Arcangeli wrote:

> The PG_truncate is needed as well because we can't know in do_no_page if
> page->mapping is legitimate null or not (think bttv and other device
> drivers returning page->mapping null because they're private but not
> reserved pages etc..)
> 
> From: Andrea Arcangeli <andrea@suse.de>
> Subject: avoid race between invalidate_inode_pages2 and do_no_page
> 
> Use page lock and new bitflag to serialize.
> 

As clean upstream solution, could we make truncatable (ie. regular
file backed) mappings set a vma flag which changes its nopage protocol
to return a locked page?

filemap_nopage itself, rather than do_no_page would then take care of
handling the truncate races. That seems to be a better layer to handle
it in.

Also, after this there should be no reason for truncate_count, right?
(At least in its truncate/nopage capacity.) If so, we should remove it
as part of the same patch / patchset.

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 

  reply	other threads:[~2006-04-02  9:00 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-13 19:37 smp race fix between invalidate_inode_pages* and do_no_page Andrea Arcangeli
2005-12-13 21:02 ` Andrew Morton
2005-12-13 21:14   ` Andrea Arcangeli
2005-12-16 13:51     ` Andrea Arcangeli
2006-01-10  6:24       ` Andrea Arcangeli
2006-01-10  6:48         ` Andrea Arcangeli
2006-01-11  4:08         ` Nick Piggin
2006-01-11  8:23           ` Andrea Arcangeli
2006-01-11  8:51             ` Andrew Morton
2006-01-11  9:02               ` Andrea Arcangeli
2006-01-11  9:06                 ` Andrew Morton
2006-01-11  9:13                   ` Andrea Arcangeli
2006-01-11 20:49                     ` Hugh Dickins
2006-01-11 21:05                       ` Andrew Morton
2006-01-13  7:35                       ` Nick Piggin
2006-01-13  7:47                         ` Andrew Morton
2006-01-13 10:37                           ` Nick Piggin
2006-03-31 12:36                             ` Andrea Arcangeli
2006-04-02  5:17                               ` Nick Piggin [this message]
2006-04-02  5:21                               ` Andrew Morton
2006-04-07 19:18                                 ` Hugh Dickins
2006-01-11  9:39                 ` Nick Piggin
2006-01-11  9:34             ` Nick Piggin

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