Re: [PATCH 03/13] writeback: per-task rate limit onbalance_dirty_pages()

[Wu Fengguang]

> +	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;

Sorry here is a bug fix for the above line, it's also pushed to the
git tree.

Thanks,
Fengguang
---
Subject: writeback: fix increasement of nr_dirtied_pause
Date: Wed Nov 17 22:31:26 CST 2010

Fix a bug that

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

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

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

--- linux-next.orig/mm/page-writeback.c	2010-11-17 22:31:09.000000000 +0800
+++ linux-next/mm/page-writeback.c	2010-11-17 22:31:23.000000000 +0800
@@ -662,7 +662,7 @@ 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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