From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>, Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-mm <linux-mm@kvack.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 04/13] writeback: prevent duplicate balance_dirty_pages_ratelimited() calls
Date: Wed, 17 Nov 2010 11:58:25 +0800 [thread overview]
Message-ID: <20101117035905.873681033@intel.com> (raw)
Andrew,
References: <20101117035821.000579293@intel.com>
Content-Disposition: inline; filename=writeback-fix-duplicate-bdp-calls.patch
When dd in 512bytes, balance_dirty_pages_ratelimited() used to be called
8 times for the same page, even if the page is only dirtied once. Fix it
with a (slightly racy) PageDirty() test.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/filemap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- linux-next.orig/mm/filemap.c 2010-11-16 22:20:08.000000000 +0800
+++ linux-next/mm/filemap.c 2010-11-16 22:45:05.000000000 +0800
@@ -2258,6 +2258,7 @@ static ssize_t generic_perform_write(str
long status = 0;
ssize_t written = 0;
unsigned int flags = 0;
+ unsigned int dirty;
/*
* Copies from kernel address space cannot fail (NFSD is a big user).
@@ -2306,6 +2307,7 @@ again:
pagefault_enable();
flush_dcache_page(page);
+ dirty = PageDirty(page);
mark_page_accessed(page);
status = a_ops->write_end(file, mapping, pos, bytes, copied,
page, fsdata);
@@ -2332,7 +2334,8 @@ again:
pos += copied;
written += copied;
- balance_dirty_pages_ratelimited(mapping);
+ if (!dirty)
+ balance_dirty_pages_ratelimited(mapping);
} while (iov_iter_count(i));
--
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next reply other threads:[~2010-11-17 3:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-17 3:58 Wu Fengguang [this message]
-- strict thread matches above, loose matches on Subject: below --
2010-11-17 4:27 [PATCH 00/13] IO-less dirty throttling v2 Wu Fengguang
2010-11-17 4:27 ` [PATCH 04/13] writeback: prevent duplicate balance_dirty_pages_ratelimited() calls Wu Fengguang
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