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From: Dave Chinner <david@fromorbit.com>
To: Alex Elder <aelder@sgi.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 20/34] xfs: remove all the inodes on a buffer from the AIL in bulk
Date: Wed, 22 Dec 2010 14:49:02 +1100	[thread overview]
Message-ID: <20101222034902.GF4907@dastard> (raw)
In-Reply-To: <1292984446.2408.358.camel@doink>

On Tue, Dec 21, 2010 at 08:20:46PM -0600, Alex Elder wrote:
> On Tue, 2010-12-21 at 18:29 +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > When inode buffer IO completes, usually all of the inodes are removed from the
> > AIL. This involves processing them one at a time and taking the AIL lock once
> > for every inode. When all CPUs are processing inode IO completions, this causes
> > excessive amount sof contention on the AIL lock.
> > 
> > Instead, change the way we process inode IO completion in the buffer
> > IO done callback. Allow the inode IO done callback to walk the list
> > of IO done callbacks and pull all the inodes off the buffer in one
> > go and then process them as a batch.
> > 
> > Once all the inodes for removal are collected, take the AIL lock
> > once and do a bulk removal operation to minimise traffic on the AIL
> > lock.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> One question, below.		-Alex
> 
> . . .
> 
> > @@ -861,28 +910,37 @@ xfs_iflush_done(
> >  	 * the lock since it's cheaper, and then we recheck while
> >  	 * holding the lock before removing the inode from the AIL.
> >  	 */
> > -	if (iip->ili_logged && lip->li_lsn == iip->ili_flush_lsn) {
> > +	if (need_ail) {
> > +		struct xfs_log_item *log_items[need_ail];
> 
> What's the worst-case value of need_ail we might see here?

The number of inodes in a cluster. That's 32 for 256 byte inodes
with the current 8k cluster size.

Cheers,

Dave
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2010-12-22  3:47 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
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 [this message]
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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