From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 30/34] xfs: convert l_tail_lsn to an atomic variable.
Date: Wed, 29 Dec 2010 07:52:22 -0500 [thread overview]
Message-ID: <20101229125221.GA1035@infradead.org> (raw)
In-Reply-To: <1292916570-25015-31-git-send-email-david@fromorbit.com>
On Tue, Dec 21, 2010 at 06:29:26PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> log->l_tail_lsn is currently protected by the log grant lock. The
> lock is only needed for serialising readers against writers, so we
> don't really need the lock if we make the l_tail_lsn variable an
> atomic. Converting the l_tail_lsn variable to an atomic64_t means we
> can start to peel back the grant lock from various operations.
>
> Also, provide functions to safely crack an atomic LSN variable into
> it's component pieces and to recombined the components into an
> atomic variable. Use them where appropriate.
>
> This also removes the need for explicitly holding a spinlock to read
> the l_tail_lsn on 32 bit platforms.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
> /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
> - log->l_tail_lsn = xlog_assign_lsn(1, 0);
> - atomic64_set(&log->l_last_sync_lsn, xlog_assign_lsn(1, 0));
> + xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
> + xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
It might be worth to remove the rather pointless comment above.
> BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
> XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
>
> -
> static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
spurious whitespace change
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next prev parent reply other threads:[~2010-12-29 12:50 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
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 [this message]
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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