From: Nikolay Borisov <nborisov@suse.com>
To: Dave Chinner <david@fromorbit.com>, linux-xfs@vger.kernel.org
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 16/24] xfs: Lower CIL flush limit for large logs
Date: Sun, 4 Aug 2019 20:12:45 +0300 [thread overview]
Message-ID: <b8b711fc-ba44-b510-91e8-8b6c247c30f3@suse.com> (raw)
In-Reply-To: <20190801021752.4986-17-david@fromorbit.com>
On 1.08.19 г. 5:17 ч., Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> The current CIL size aggregation limit is 1/8th the log size. This
> means for large logs we might be aggregating at least 250MB of dirty objects
> in memory before the CIL is flushed to the journal. With CIL shadow
> buffers sitting around, this means the CIL is often consuming >500MB
> of temporary memory that is all allocated under GFP_NOFS conditions.
>
> FLushing the CIL can take some time to do if there is other IO
> ongoing, and can introduce substantial log force latency by itself.
> It also pins the memory until the objects are in the AIL and can be
> written back and reclaimed by shrinkers. Hence this threshold also
> tends to determine the minimum amount of memory XFS can operate in
> under heavy modification without triggering the OOM killer.
>
> Modify the CIL space limit to prevent such huge amounts of pinned
> metadata from aggregating. We can 2MB of log IO in flight at once,
There is a word missing between 'can' and '2MB'
> so limit aggregation to 8x this size (arbitrary). This has some
> impact on performance (5-10% decrease on 16-way fsmark) and
> increases the amount of log traffic (~50% on same workload) but it
> is necessary to prevent rampant OOM killing under iworkloads that
> modify large amounts of metadata under heavy memory pressure.
>
> This was found via trace analysis or AIL behaviour. e.g. insertion
s/or/of/
> from a single CIL flush:
<snip>
next prev parent reply other threads:[~2019-08-04 17:12 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 2:17 [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Dave Chinner
2019-08-01 2:17 ` [PATCH 01/24] mm: directed shrinker work deferral Dave Chinner
2019-08-02 15:27 ` Brian Foster
2019-08-04 1:49 ` Dave Chinner
2019-08-05 17:42 ` Brian Foster
2019-08-05 23:43 ` Dave Chinner
2019-08-06 12:27 ` Brian Foster
2019-08-06 22:22 ` Dave Chinner
2019-08-07 11:13 ` Brian Foster
2019-08-01 2:17 ` [PATCH 02/24] shrinkers: use will_defer for GFP_NOFS sensitive shrinkers Dave Chinner
2019-08-02 15:27 ` Brian Foster
2019-08-04 1:50 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 03/24] mm: factor shrinker work calculations Dave Chinner
2019-08-02 15:08 ` Nikolay Borisov
2019-08-04 2:05 ` Dave Chinner
2019-08-02 15:31 ` Brian Foster
2019-08-01 2:17 ` [PATCH 04/24] shrinker: defer work only to kswapd Dave Chinner
2019-08-02 15:34 ` Brian Foster
2019-08-04 16:48 ` Nikolay Borisov
2019-08-04 21:37 ` Dave Chinner
2019-08-07 16:12 ` kbuild test robot
2019-08-07 18:00 ` kbuild test robot
2019-08-01 2:17 ` [PATCH 05/24] shrinker: clean up variable types and tracepoints Dave Chinner
2019-08-01 2:17 ` [PATCH 06/24] mm: reclaim_state records pages reclaimed, not slabs Dave Chinner
2019-08-01 2:17 ` [PATCH 07/24] mm: back off direct reclaim on excessive shrinker deferral Dave Chinner
2019-08-01 2:17 ` [PATCH 08/24] mm: kswapd backoff for shrinkers Dave Chinner
2019-08-01 2:17 ` [PATCH 09/24] xfs: don't allow log IO to be throttled Dave Chinner
2019-08-01 13:39 ` Chris Mason
2019-08-01 23:58 ` Dave Chinner
2019-08-02 8:12 ` Christoph Hellwig
2019-08-02 14:11 ` Chris Mason
2019-08-02 18:34 ` Matthew Wilcox
2019-08-02 23:28 ` Dave Chinner
2019-08-05 18:32 ` Chris Mason
2019-08-05 23:09 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 10/24] xfs: fix missed wakeup on l_flush_wait Dave Chinner
2019-08-01 2:17 ` [PATCH 11/24] xfs:: account for memory freed from metadata buffers Dave Chinner
2019-08-01 8:16 ` Christoph Hellwig
2019-08-01 9:21 ` Dave Chinner
2019-08-06 5:51 ` Christoph Hellwig
2019-08-01 2:17 ` [PATCH 12/24] xfs: correctly acount for reclaimable slabs Dave Chinner
2019-08-06 5:52 ` Christoph Hellwig
2019-08-06 21:05 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 13/24] xfs: synchronous AIL pushing Dave Chinner
2019-08-05 17:51 ` Brian Foster
2019-08-05 23:21 ` Dave Chinner
2019-08-06 12:29 ` Brian Foster
2019-08-01 2:17 ` [PATCH 14/24] xfs: tail updates only need to occur when LSN changes Dave Chinner
2019-08-05 17:53 ` Brian Foster
2019-08-05 23:28 ` Dave Chinner
2019-08-06 5:33 ` Dave Chinner
2019-08-06 12:53 ` Brian Foster
2019-08-06 21:11 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 15/24] xfs: eagerly free shadow buffers to reduce CIL footprint Dave Chinner
2019-08-05 18:03 ` Brian Foster
2019-08-05 23:33 ` Dave Chinner
2019-08-06 12:57 ` Brian Foster
2019-08-06 21:21 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 16/24] xfs: Lower CIL flush limit for large logs Dave Chinner
2019-08-04 17:12 ` Nikolay Borisov [this message]
2019-08-01 2:17 ` [PATCH 17/24] xfs: don't block kswapd in inode reclaim Dave Chinner
2019-08-06 18:21 ` Brian Foster
2019-08-06 21:27 ` Dave Chinner
2019-08-07 11:14 ` Brian Foster
2019-08-01 2:17 ` [PATCH 18/24] xfs: reduce kswapd blocking on inode locking Dave Chinner
2019-08-06 18:22 ` Brian Foster
2019-08-06 21:33 ` Dave Chinner
2019-08-07 11:30 ` Brian Foster
2019-08-07 23:16 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 19/24] xfs: kill background reclaim work Dave Chinner
2019-08-01 2:17 ` [PATCH 20/24] xfs: use AIL pushing for inode reclaim IO Dave Chinner
2019-08-07 18:09 ` Brian Foster
2019-08-07 23:10 ` Dave Chinner
2019-08-08 16:20 ` Brian Foster
2019-08-01 2:17 ` [PATCH 21/24] xfs: remove mode from xfs_reclaim_inodes() Dave Chinner
2019-08-01 2:17 ` [PATCH 22/24] xfs: track reclaimable inodes using a LRU list Dave Chinner
2019-08-08 16:36 ` Brian Foster
2019-08-09 0:10 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 23/24] xfs: reclaim inodes from the LRU Dave Chinner
2019-08-08 16:39 ` Brian Foster
2019-08-09 1:20 ` Dave Chinner
2019-08-09 12:36 ` Brian Foster
2019-08-11 2:17 ` Dave Chinner
2019-08-11 12:46 ` Brian Foster
2019-08-01 2:17 ` [PATCH 24/24] xfs: remove unusued old inode reclaim code Dave Chinner
2019-08-06 5:57 ` [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Christoph Hellwig
2019-08-06 21:37 ` Dave Chinner
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