From: Jan Kara <jack@suse.cz>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>,
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>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 6/6] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages
Date: Mon, 2 Aug 2010 20:31:10 +0200 [thread overview]
Message-ID: <20100802183109.GJ3278@quack.suse.cz> (raw)
In-Reply-To: <20100731103321.GI3571@csn.ul.ie>
On Sat 31-07-10 11:33:22, Mel Gorman wrote:
> On Fri, Jul 30, 2010 at 03:06:01PM -0700, Andrew Morton wrote:
> > Sigh. We have sooo many problems with writeback and latency. Read
> > https://bugzilla.kernel.org/show_bug.cgi?id=12309 and weep.
>
> You aren't joking.
>
> > Everyone's
> > running away from the issue and here we are adding code to solve some
> > alleged stack-overflow problem which seems to be largely a non-problem,
> > by making changes which may worsen our real problems.
> >
>
> As it is, filesystems are beginnning to ignore writeback from direct
> reclaim - such as xfs and btrfs. I'm lead to believe that ext3
> effectively ignores writeback from direct reclaim although I don't have
> access to code at the moment to double check (am on the road). So either
> way, we are going to be facing this problem so the VM might as well be
> aware of it :/
Umm, ext3 should be handling direct reclaim just fine. ext4 does however
ignore it when a page does not have block already allocated (which is a
common case with delayed allocation).
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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next prev parent reply other threads:[~2010-08-02 18:31 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-30 13:36 [PATCH 0/6] Reduce writeback from page reclaim context V6 Mel Gorman
2010-07-30 13:36 ` [PATCH 1/6] vmscan: tracing: Roll up of patches currently in mmotm Mel Gorman
2010-07-30 14:04 ` Frederic Weisbecker
2010-07-30 14:12 ` Mel Gorman
2010-07-30 14:15 ` Frederic Weisbecker
2010-07-30 13:36 ` [PATCH 2/6] vmscan: tracing: Update trace event to track if page reclaim IO is for anon or file pages Mel Gorman
2010-07-30 13:36 ` [PATCH 3/6] vmscan: tracing: Update post-processing script to distinguish between anon and file IO from page reclaim Mel Gorman
2010-07-30 13:36 ` [PATCH 4/6] vmscan: tracing: Correct units in post-processing script Mel Gorman
2010-07-30 13:36 ` [PATCH 5/6] vmscan: Do not writeback filesystem pages in direct reclaim Mel Gorman
2010-08-05 6:59 ` KOSAKI Motohiro
2010-08-05 14:15 ` Mel Gorman
2010-07-30 13:37 ` [PATCH 6/6] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages Mel Gorman
2010-07-30 22:06 ` Andrew Morton
2010-07-30 22:40 ` Trond Myklebust
2010-08-01 8:19 ` KOSAKI Motohiro
2010-08-01 16:21 ` Trond Myklebust
2010-08-02 7:57 ` KOSAKI Motohiro
2010-07-31 10:33 ` Mel Gorman
2010-08-02 18:31 ` Jan Kara [this message]
2010-08-01 11:15 ` Wu Fengguang
2010-08-01 11:56 ` Wu Fengguang
2010-08-01 13:03 ` Wu Fengguang
[not found] ` <80868B70-B17D-4007-AA15-5C11F0F95353@xyke.com>
2010-08-02 2:30 ` Wu Fengguang
2010-08-05 6:45 ` KOSAKI Motohiro
2010-08-05 14:09 ` Mel Gorman
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