From: Nick Piggin <npiggin@suse.de>
To: Dave Chinner <david@fromorbit.com>
Cc: torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, xfs@oss.sgi.com,
akpm@linux-foundation.org
Subject: Re: [PATCH 4/6] writeback: pay attention to wbc->nr_to_write in write_cache_pages
Date: Tue, 8 Jun 2010 15:43:30 +1000 [thread overview]
Message-ID: <20100608054330.GS26335@laptop> (raw)
In-Reply-To: <1275957487-23633-5-git-send-email-david@fromorbit.com>
On Tue, Jun 08, 2010 at 10:38:05AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> If a filesystem writes more than one page in ->writepage, write_cache_pages
> fails to notice this and continues to attempt writeback when wbc->nr_to_write
> has gone negative - this trace was captured from XFS:
>
>
> wbc_writeback_start: towrt=1024
> wbc_writepage: towrt=1024
> wbc_writepage: towrt=0
> wbc_writepage: towrt=-1
> wbc_writepage: towrt=-5
> wbc_writepage: towrt=-21
> wbc_writepage: towrt=-85
>
> This has adverse effects on filesystem writeback behaviour. write_cache_pages()
> needs to terminate after a certain number of pages are written, not after a
> certain number of calls to ->writepage are made. This is a regression
> introduced by 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 ("vfs: Add
> no_nrwrite_index_update writeback control flag"), but cannot be reverted
> directly due to subsequent bug fixes that have gone in on top of it.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Nick Piggin <npiggin@suse.de>
next prev parent reply other threads:[~2010-06-08 5:43 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-08 0:38 [PATCH 0/6] writeback: tracing and fixes V4 Dave Chinner
2010-06-08 0:38 ` [PATCH 1/6] writeback: initial tracing support Dave Chinner
2010-06-08 0:38 ` [PATCH 2/6] writeback: Add tracing to balance_dirty_pages Dave Chinner
2010-06-08 0:38 ` [PATCH 3/6] writeback: Add tracing to write_cache_pages Dave Chinner
2010-06-08 0:38 ` [PATCH 4/6] writeback: pay attention to wbc->nr_to_write in write_cache_pages Dave Chinner
2010-06-08 5:43 ` Nick Piggin [this message]
2010-06-08 0:38 ` [PATCH 5/6] xfs: remove nr_to_write writeback windup Dave Chinner
2010-06-08 0:38 ` [PATCH 6/6] writeback: limit write_cache_pages integrity scanning to current EOF Dave Chinner
2010-06-08 5:38 ` Nick Piggin
2010-06-08 6:59 ` Dave Chinner
2010-06-08 5:44 ` [PATCH 0/6] writeback: tracing and fixes V4 Nick Piggin
2010-06-08 17:41 ` Linus Torvalds
2010-06-08 17:50 ` Andrew Morton
2010-06-08 22:46 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2010-06-03 23:55 [PATCH 0/6] writeback: tracing and fixes V3 Dave Chinner
2010-06-03 23:55 ` [PATCH 4/6] writeback: pay attention to wbc->nr_to_write in write_cache_pages Dave Chinner
2010-06-04 7:48 ` Christoph Hellwig
2010-05-25 10:54 [PATCH 0/6] writeback: tracing and fixes Dave Chinner
2010-05-25 10:54 ` [PATCH 4/6] writeback: pay attention to wbc->nr_to_write in write_cache_pages Dave Chinner
2010-05-25 11:11 ` Christoph Hellwig
2010-05-27 21:32 ` Andrew Morton
2010-05-28 0:56 ` Dave Chinner
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