From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wu Fengguang <fengguang.wu@intel.com>
Subject: [PATCH 19/47] writeback: fix increasement of nr_dirtied_pause
Date: Mon, 13 Dec 2010 14:43:08 +0800
Message-ID: <20101213064839.291896969@intel.com>
References: <20101213064249.648862451@intel.com>
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To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>, Wu Fengguang <fengguang.wu@intel.com>, Christoph Hellwig <hch@lst.de>, Trond Myklebust <Trond.Myklebust@netapp.com>, Dave Chinner <david@fromorbit.com>, Theodore Ts'o <tytso@mit.edu>, Chris Mason <chris.mason@oracle.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Mel Gorman <mel@csn.ul.ie>, Rik van Riel <riel@redhat.com>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Greg Thelen <gthelen@google.com>, Minchan Kim <minchan.kim@gmail.com>, linux-mm <linux-mm@kvack.org>, linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
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Fix a bug that

	current->nr_dirtied_pause += current->nr_dirtied_pause >> 5;

does not effectively increase nr_dirtied_pause when it's less than 32.
Thus nr_dirtied_pause may never grow up.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 mm/page-writeback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next.orig/mm/page-writeback.c	2010-12-08 22:44:27.000000000 +0800
+++ linux-next/mm/page-writeback.c	2010-12-08 22:44:28.000000000 +0800
@@ -700,7 +700,7 @@ pause:
 	if (pause == 0 && nr_dirty < background_thresh)
 		current->nr_dirtied_pause = ratelimit_pages(bdi);
 	else if (pause == 1)
-		current->nr_dirtied_pause += current->nr_dirtied_pause >> 5;
+		current->nr_dirtied_pause += current->nr_dirtied_pause / 32 + 1;
 	else if (pause >= HZ/10)
 		/*
 		 * when repeated, writing 1 page per 100ms on slow devices,


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