From: Ben Myers <bpm@sgi.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [patch 09/19] xfs: cleanup xfs_qm_dqlookup
Date: Tue, 13 Dec 2011 11:30:46 -0600 [thread overview]
Message-ID: <20111213173046.GA29840@sgi.com> (raw)
In-Reply-To: <20111206215854.196332791@bombadil.infradead.org>
On Tue, Dec 06, 2011 at 04:58:15PM -0500, Christoph Hellwig wrote:
> Rearrange the code to avoid the conditional locking around the flist_locked
> variable. This means we lose a (rather pointless) assert, and hold the
> freelist lock a bit longer for one corner case.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Dave Chinner <dchinner@redhat.com>
Looks good.
Reviewed-by: Ben Myers <bpm@sgi.com>
> ---
> fs/xfs/xfs_dquot.c | 25 +++++--------------------
> 1 file changed, 5 insertions(+), 20 deletions(-)
>
> Index: xfs/fs/xfs/xfs_dquot.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_dquot.c 2011-10-27 22:40:02.250173174 +0200
> +++ xfs/fs/xfs/xfs_dquot.c 2011-10-27 22:40:02.770171231 +0200
> @@ -710,12 +710,9 @@ xfs_qm_dqlookup(
> xfs_dquot_t **O_dqpp)
> {
> xfs_dquot_t *dqp;
> - uint flist_locked;
>
> ASSERT(mutex_is_locked(&qh->qh_lock));
>
> - flist_locked = B_FALSE;
> -
> /*
> * Traverse the hashchain looking for a match
> */
> @@ -750,31 +747,19 @@ xfs_qm_dqlookup(
> xfs_dqlock(dqp);
> dqp->dq_flags &= ~(XFS_DQ_WANT);
> }
> - flist_locked = B_TRUE;
> - }
> -
> - /*
> - * id couldn't have changed; we had the hashlock all
> - * along
> - */
> - ASSERT(be32_to_cpu(dqp->q_core.d_id) == id);
>
> - if (flist_locked) {
> - if (dqp->q_nrefs != 0) {
> - mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
> - flist_locked = B_FALSE;
> - } else {
> + if (dqp->q_nrefs == 0) {
Ah. We have to check this again because we would have unlocked and
reaquired the dqlock when we went for the free list lock in the
contended case.
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next prev parent reply other threads:[~2011-12-13 17:30 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-06 21:58 [patch 00/19] Linux 3.3 patchqueue Christoph Hellwig
2011-12-06 21:58 ` [patch 01/19] xfs: remove the deprecated nodelaylog option Christoph Hellwig
2011-12-07 21:44 ` Ben Myers
2011-12-08 16:12 ` Christoph Hellwig
2011-12-08 16:14 ` Ben Myers
2011-12-06 21:58 ` [patch 02/19] xfs: cleanup the transaction commit path a bit Christoph Hellwig
2011-12-08 17:44 ` Ben Myers
2011-12-06 21:58 ` [patch 03/19] xfs: remove the lid_size field in struct log_item_desc Christoph Hellwig
2011-12-08 18:35 ` Ben Myers
2011-12-06 21:58 ` [patch 04/19] xfs: untange SYNC_WAIT and SYNC_TRYLOCK meanings for xfs_qm_dqflush Christoph Hellwig
2011-12-08 21:10 ` Ben Myers
2011-12-06 21:58 ` [patch 05/19] xfs: make sure to really flush all dquots in xfs_qm_quotacheck Christoph Hellwig
2011-12-08 21:36 ` Ben Myers
2011-12-06 21:58 ` [patch 06/19] xfs: remove xfs_qm_sync Christoph Hellwig
2011-12-12 18:25 ` Ben Myers
2011-12-06 21:58 ` [patch 07/19] xfs: remove the sync_mode argument to xfs_qm_dqflush_all Christoph Hellwig
2011-12-12 22:33 ` Ben Myers
2011-12-06 21:58 ` [patch 08/19] xfs: cleanup dquot locking helpers Christoph Hellwig
2011-12-12 23:12 ` Ben Myers
2011-12-06 21:58 ` [patch 09/19] xfs: cleanup xfs_qm_dqlookup Christoph Hellwig
2011-12-13 17:30 ` Ben Myers [this message]
2011-12-06 21:58 ` [patch 10/19] xfs: remove XFS_DQ_INACTIVE Christoph Hellwig
2011-12-13 20:26 ` Ben Myers
2011-12-06 21:58 ` [patch 11/19] xfs: implement lazy removal for the dquot freelist Christoph Hellwig
2011-12-14 22:13 ` Ben Myers
2011-12-06 21:58 ` [patch 12/19] xfs: flatten the dquot lock ordering Christoph Hellwig
2011-12-13 19:44 ` Dave Chinner
2011-12-14 22:18 ` Ben Myers
2011-12-15 3:13 ` Ben Myers
2011-12-06 21:58 ` [patch 13/19] xfs: nest qm_dqfrlist_lock inside the dquot qlock Christoph Hellwig
2011-12-15 3:02 ` Ben Myers
2011-12-06 21:58 ` [patch 14/19] xfs: simplify xfs_qm_dqattach_grouphint Christoph Hellwig
2011-12-15 4:55 ` Ben Myers
2011-12-06 21:58 ` [patch 15/19] xfs: simplify xfs_qm_detach_gdquots Christoph Hellwig
2011-12-15 16:43 ` Ben Myers
2011-12-16 0:48 ` Dave Chinner
2011-12-16 21:33 ` Ben Myers
2011-12-06 21:58 ` [patch 16/19] xfs: add a xfs_dqhold helper Christoph Hellwig
2011-12-15 16:56 ` Ben Myers
2011-12-06 21:58 ` [patch 17/19] xfs: merge xfs_qm_dqinit_core into the only caller Christoph Hellwig
2011-12-15 17:00 ` Ben Myers
2011-12-06 21:58 ` [patch 18/19] xfs: kill xfs_qm_idtodq Christoph Hellwig
2011-12-15 20:07 ` Ben Myers
2011-12-06 21:58 ` [patch 19/19] xfs: remove XFS_QMOPT_DQSUSER Christoph Hellwig
2011-12-15 20:22 ` Ben Myers
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