Subject: Re: [PATCH 03/12] tracing, vmscan: Add trace event when a page is
	written
From: Larry Woodman <lwoodman@redhat.com>
To: Mel Gorman <mel@csn.ul.ie>
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>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Andrew Morton <akpm@linux-foundation.org>
In-Reply-To: <1276514273-27693-4-git-send-email-mel@csn.ul.ie>
References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie>
	 <1276514273-27693-4-git-send-email-mel@csn.ul.ie>
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Date: Mon, 14 Jun 2010 17:02:51 -0400
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On Mon, 2010-06-14 at 12:17 +0100, Mel Gorman wrote:
> This patch adds a trace event for when page reclaim queues a page for IO and
> records whether it is synchronous or asynchronous. Excessive synchronous
> IO for a process can result in noticeable stalls during direct reclaim.
> Excessive IO from page reclaim may indicate that the system is seriously
> under provisioned for the amount of dirty pages that exist.
> 
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>

Acked-by: Larry Woodman <lwoodman@redhat.com>


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