From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 8/8] vmscan: Kick flusher threads to clean pages when
 reclaim is encountering dirty pages
Date: Mon, 19 Jul 2010 10:23:49 -0400
Message-ID: <20100719142349.GE12510@infradead.org>
References: <1279545090-19169-1-git-send-email-mel@csn.ul.ie>
 <1279545090-19169-9-git-send-email-mel@csn.ul.ie>
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Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Nick Piggin <npiggin@suse.de>, Rik van Riel <riel@redhat.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Christoph Hellwig <hch@infradead.org>,
	Wu Fengguang <fengguang.wu@intel.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>
To: Mel Gorman <mel@csn.ul.ie>
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On Mon, Jul 19, 2010 at 02:11:30PM +0100, Mel Gorman wrote:
> +	/*
> +	 * If reclaim is encountering dirty pages, it may be because
> +	 * dirty pages are reaching the end of the LRU even though
> +	 * the dirty_ratio may be satisified. In this case, wake
> +	 * flusher threads to pro-actively clean some pages
> +	 */
> +	wakeup_flusher_threads(laptop_mode ? 0 : nr_dirty + nr_dirty / 2);
> +

Where is the laptop-mode magic coming from?

And btw, at least currently wakeup_flusher_threads writes back nr_pages
for each BDI, which might not be what you want.  Then again probably
no caller wants it, but I don't see an easy way to fix it.