From: Mel Gorman <mgorman@suse.de>
To: Christoph Hellwig <hch@infradead.org>
Cc: Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>, XFS <xfs@oss.sgi.com>,
Dave Chinner <david@fromorbit.com>,
Johannes Weiner <jweiner@redhat.com>,
Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
Rik van Riel <riel@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>
Subject: Re: [PATCH 5/5] mm: writeback: Prioritise dirty inodes encountered by direct reclaim for background flushing
Date: Thu, 14 Jul 2011 16:49:15 +0100 [thread overview]
Message-ID: <20110714154915.GV7529@suse.de> (raw)
In-Reply-To: <20110714150959.GA30936@infradead.org>
On Thu, Jul 14, 2011 at 11:09:59AM -0400, Christoph Hellwig wrote:
> On Wed, Jul 13, 2011 at 03:31:27PM +0100, Mel Gorman wrote:
> > It is preferable that no dirty pages are dispatched from the page
> > reclaim path. If reclaim is encountering dirty pages, it implies that
> > either reclaim is getting ahead of writeback or use-once logic has
> > prioritise pages for reclaiming that are young relative to when the
> > inode was dirtied.
>
> what does this buy us?
Very little. The vague intention was to avoid a situation where kswapds
priority was raised such that it had to write pages to clean a
particular zone.
> If at all we should prioritize by a zone,
> e.g. tell write_cache_pages only to bother with writing things out
> if the dirty page is in a given zone. We'd probably still cluster
> around it to make sure we get good I/O patterns, but would only start
> I/O if it has a page we actually care about.
>
That would make more sense. I've dropped this patch entirely.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2011-07-14 15:49 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-13 14:31 [RFC PATCH 0/5] Reduce filesystem writeback from page reclaim (again) Mel Gorman
2011-07-13 14:31 ` [PATCH 1/5] mm: vmscan: Do not writeback filesystem pages in direct reclaim Mel Gorman
2011-07-13 23:34 ` Dave Chinner
2011-07-14 6:17 ` Mel Gorman
2011-07-14 1:38 ` KAMEZAWA Hiroyuki
2011-07-14 4:46 ` Christoph Hellwig
2011-07-14 4:46 ` KAMEZAWA Hiroyuki
2011-07-14 15:07 ` Christoph Hellwig
2011-07-14 23:55 ` KAMEZAWA Hiroyuki
2011-07-15 2:22 ` Dave Chinner
2011-07-18 2:22 ` Dave Chinner
2011-07-18 3:06 ` Dave Chinner
2011-07-14 6:19 ` Mel Gorman
2011-07-14 6:17 ` KAMEZAWA Hiroyuki
2011-07-13 14:31 ` [PATCH 2/5] mm: vmscan: Do not writeback filesystem pages in kswapd except in high priority Mel Gorman
2011-07-13 23:37 ` Dave Chinner
2011-07-14 6:29 ` Mel Gorman
2011-07-14 11:52 ` Dave Chinner
2011-07-14 13:17 ` Mel Gorman
2011-07-15 3:12 ` Dave Chinner
2011-07-13 14:31 ` [PATCH 3/5] mm: vmscan: Throttle reclaim if encountering too many dirty pages under writeback Mel Gorman
2011-07-13 23:41 ` Dave Chinner
2011-07-14 6:33 ` Mel Gorman
2011-07-13 14:31 ` [PATCH 4/5] mm: vmscan: Immediately reclaim end-of-LRU dirty pages when writeback completes Mel Gorman
2011-07-13 16:40 ` Johannes Weiner
2011-07-13 17:15 ` Mel Gorman
2011-07-13 14:31 ` [PATCH 5/5] mm: writeback: Prioritise dirty inodes encountered by direct reclaim for background flushing Mel Gorman
2011-07-13 21:39 ` Jan Kara
2011-07-14 0:09 ` Dave Chinner
2011-07-14 7:03 ` Mel Gorman
2011-07-13 23:56 ` Dave Chinner
2011-07-14 7:30 ` Mel Gorman
2011-07-14 15:09 ` Christoph Hellwig
2011-07-14 15:49 ` Mel Gorman [this message]
2011-07-13 15:31 ` [RFC PATCH 0/5] Reduce filesystem writeback from page reclaim (again) Mel Gorman
2011-07-14 0:33 ` Dave Chinner
2011-07-14 4:51 ` Christoph Hellwig
2011-07-14 7:37 ` Mel Gorman
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