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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 07/34] xfs: don't truncate prealloc from frequently accessed inodes
Date: Tue, 21 Dec 2010 11:45:41 -0500	[thread overview]
Message-ID: <20101221164541.GA9093@infradead.org> (raw)
In-Reply-To: <1292916570-25015-8-git-send-email-david@fromorbit.com>

On Tue, Dec 21, 2010 at 06:29:03PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> A long standing problem for streaming write?? through the NFS server
> has been that the NFS server opens and closes file descriptors on an
> inode for every write. The result of this behaviour is that the
> ->release() function is called on every close and that results in
> XFS truncating speculative preallocation beyond the EOF.  This has
> an adverse effect on file layout when multiple files are being
> written at the same time - they interleave their extents and can
> result in severe fragmentation.
> 
> To avoid this problem, keep a count of the number of ->release calls
> made on an inode. For most cases, an inode is only going to be opened
> once for writing and then closed again during it's lifetime in
> cache. Hence if there are multiple ->release calls, there is a good
> chance that the inode is being accessed by the NFS server. Hence
> count up every time ->release is called while there are delalloc
> blocks still outstanding on the inode.
> 
> If this count is non-zero when ->release is next called, then do no
> truncate away the speculative preallocation - leave it there so that
> subsequent writes do not need to reallocate the delalloc space. This
> will prevent interleaving of extents of different inodes written
> concurrently to the same AG.
> 
> If we get this wrong, it is not a big deal as we truncate
> speculative allocation beyond EOF anyway in xfs_inactive() when the
> inode is thrown out of the cache.

Looks good.

> The new counter in the struct xfs_inode fits into a hole in the
> structure on 64 bit machines, so does not grow the size of the inode
> at all.


There's no counter any more. (the text further above could also use some
minor updates for that)

Reviewed-by: Christoph Hellwig <hch@lst.de>

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  reply	other threads:[~2010-12-21 16:43 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-21  7:28 [PATCH 00/34] xfs: scalability patchset for 2.6.38 Dave Chinner
2010-12-21  7:28 ` [PATCH 01/34] xfs: provide a inode iolock lockdep class Dave Chinner
2010-12-21 15:15   ` Christoph Hellwig
2010-12-21  7:28 ` [PATCH 02/34] xfs: use KM_NOFS for allocations during attribute list operations Dave Chinner
2010-12-21 15:16   ` Christoph Hellwig
2010-12-21  7:28 ` [PATCH 03/34] lib: percpu counter add unless less than functionality Dave Chinner
2010-12-22  2:20   ` Alex Elder
2010-12-22  3:46     ` Dave Chinner
2010-12-21  7:29 ` [PATCH 04/34] xfs: use generic per-cpu counter infrastructure Dave Chinner
2010-12-21  7:29 ` [PATCH 05/34] xfs: demultiplex xfs_icsb_modify_counters() Dave Chinner
2010-12-21  7:29 ` [PATCH 06/34] xfs: dynamic speculative EOF preallocation Dave Chinner
2010-12-21 15:15   ` Christoph Hellwig
2010-12-21 21:42     ` Dave Chinner
2010-12-21 23:44       ` Dave Chinner
2010-12-22  2:29         ` Alex Elder
2010-12-29 12:56         ` Christoph Hellwig
2010-12-27 14:57   ` Alex Elder
2010-12-27 15:00   ` Alex Elder
2011-01-06 18:16   ` Christoph Hellwig
2010-12-21  7:29 ` [PATCH 07/34] xfs: don't truncate prealloc from frequently accessed inodes Dave Chinner
2010-12-21 16:45   ` Christoph Hellwig [this message]
2010-12-21  7:29 ` [PATCH 08/34] xfs: rcu free inodes Dave Chinner
2010-12-21  7:29 ` [PATCH 09/34] xfs: convert inode cache lookups to use RCU locking Dave Chinner
2010-12-21  7:29 ` [PATCH 10/34] xfs: convert pag_ici_lock to a spin lock Dave Chinner
2010-12-21  7:29 ` [PATCH 11/34] xfs: convert xfsbud shrinker to a per-buftarg shrinker Dave Chinner
2010-12-21  7:29 ` [PATCH 12/34] xfs: add a lru to the XFS buffer cache Dave Chinner
2010-12-21  7:29 ` [PATCH 13/34] xfs: connect up buffer reclaim priority hooks Dave Chinner
2010-12-21  7:29 ` [PATCH 14/34] xfs: fix EFI transaction cancellation Dave Chinner
2010-12-21  7:29 ` [PATCH 15/34] xfs: Pull EFI/EFD handling out from under the AIL lock Dave Chinner
2010-12-21  7:29 ` [PATCH 16/34] xfs: clean up xfs_ail_delete() Dave Chinner
2010-12-21  7:29 ` [PATCH 17/34] xfs: bulk AIL insertion during transaction commit Dave Chinner
2010-12-21  7:29 ` [PATCH 18/34] xfs: reduce the number of AIL push wakeups Dave Chinner
2010-12-21  7:29 ` [PATCH 19/34] xfs: consume iodone callback items on buffers as they are processed Dave Chinner
2010-12-21  7:29 ` [PATCH 20/34] xfs: remove all the inodes on a buffer from the AIL in bulk Dave Chinner
2010-12-22  2:20   ` Alex Elder
2010-12-22  3:49     ` Dave Chinner
2010-12-21  7:29 ` [PATCH 22/34] xfs: use AIL bulk delete function to implement single delete Dave Chinner
2010-12-21  7:29 ` [PATCH 23/34] xfs: convert log grant ticket queues to list heads Dave Chinner
2010-12-21  7:29 ` [PATCH 24/34] xfs: fact out common grant head/log tail verification code Dave Chinner
2010-12-21  7:29 ` [PATCH 25/34] xfs: rework log grant space calculations Dave Chinner
2010-12-21  7:29 ` [PATCH 26/34] xfs: combine grant heads into a single 64 bit integer Dave Chinner
2010-12-21  7:29 ` [PATCH 27/34] xfs: use wait queues directly for the log wait queues Dave Chinner
2010-12-21  7:29 ` [PATCH 28/34] xfs: make AIL tail pushing independent of the grant lock Dave Chinner
2010-12-21  7:29 ` [PATCH 29/34] xfs: convert l_last_sync_lsn to an atomic variable Dave Chinner
2010-12-21  7:29 ` [PATCH 30/34] xfs: convert l_tail_lsn " Dave Chinner
2010-12-29 12:52   ` Christoph Hellwig
2010-12-29 15:49   ` Alex Elder
2010-12-21  7:29 ` [PATCH 31/34] xfs: convert log grant heads to atomic variables Dave Chinner
2010-12-21  7:29 ` [PATCH 32/34] xfs: introduce new locks for the log grant ticket wait queues Dave Chinner
2010-12-21  7:29 ` [PATCH 33/34] xfs: convert grant head manipulations to lockless algorithm Dave Chinner
2010-12-21  7:29 ` [PATCH 34/34] xfs: kill useless spinlock_destroy macro Dave Chinner
2010-12-23  1:15 ` [PATCH 00/34] xfs: scalability patchset for 2.6.38 Dave Chinner

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