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From: shugelinux@gmail.com (Shuge)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] bounce:fix bug, avoid to flush dcache on slab page from jbd2.
Date: Wed, 13 Mar 2013 11:35:15 +0800	[thread overview]
Message-ID: <513FF3F3.2000509@gmail.com> (raw)
In-Reply-To: <20130313011020.GA5313@blackbox.djwong.org>

Hi all
>>> The bounce accept slab pages from jbd2, and flush dcache on them.
>>> When enabling VM_DEBUG, it will tigger VM_BUG_ON in page_mapping().
>>> So, check PageSlab to avoid it in __blk_queue_bounce().
>>>
>>> Bug URL: http://lkml.org/lkml/2013/3/7/56
>>>
>>> ...
>>>
>> ......
>>
> That sure is strange.  I didn't see any obvious reasons why we'd end up with a
>
......

     Well, this problem not only appear in arm64, but also arm32. And my 
kernel version is 3.3.0, arch is arm32.
Following the newest kernel, the problem shoulde be exist.
     I agree with Darrick's modification. Hum, if 
CONFIG_NEED_BOUNCE_POOL is not set, it also flush dcahce on
the pages of b_frozen_data, some of them are allocated by kmem_cache_alloc.
     As we know, jbd2_alloc allocate a buffer from jbd2_xk slab pool, 
when the size is smaller than PAGE_SIZE.
The b_frozen_data  is not mapped to usrspace, not aliasing cache. It cat 
be lazy flush or other. Is it right?

  reply	other threads:[~2013-03-13  3:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <5139DB90.5090302@gmail.com>
2013-03-12 22:32 ` [PATCH] bounce:fix bug, avoid to flush dcache on slab page from jbd2 Andrew Morton
2013-03-13  1:10   ` Darrick J. Wong
2013-03-13  3:35     ` Shuge [this message]
2013-03-13  4:11       ` Andrew Morton
2013-03-13  9:42         ` Russell King - ARM Linux
2013-03-13  8:50     ` Jan Kara
2013-03-13 19:44       ` Darrick J. Wong
2013-03-13 21:02         ` Jan Kara
2013-03-14 22:42           ` Darrick J. Wong
2013-03-14 23:01             ` Andrew Morton
2013-03-15 10:01             ` Jan Kara
2013-03-15 17:54               ` Darrick J. Wong
2013-03-18 17:32                 ` Jan Kara
2013-03-15 23:28               ` [PATCH] mm: Make snapshotting pages for stable writes a per-bio operation Darrick J. Wong
2013-03-18 17:41                 ` Jan Kara
2013-03-18 23:01                   ` Darrick J. Wong
2013-03-18 23:02                   ` [PATCH v3] " Darrick J. Wong
2013-03-19  8:54                     ` Jan Kara
2013-04-02 17:01                     ` Darrick J. Wong
2013-04-03 14:20                       ` Mel Gorman
2013-04-03 14:42                         ` Jan Kara
2013-04-09 18:03                           ` Darrick J. Wong
2013-03-14 22:46           ` [PATCH] bounce:fix bug, avoid to flush dcache on slab page from jbd2 Andrew Morton
2013-03-14 23:27             ` Darrick J. Wong

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