From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 10/16] xfs: nest qm_dqfrlist_lock insise the dquot qlock
Date: Mon, 5 Dec 2011 16:10:55 +1100 [thread overview]
Message-ID: <20111205051055.GQ7046@dastard> (raw)
In-Reply-To: <20111128082837.977396280@bombadil.infradead.org>
On Mon, Nov 28, 2011 at 03:27:32AM -0500, Christoph Hellwig wrote:
> Allow xfs_qm_dqput to work without trylock loops by nesting the freelist lock
> inside the dquot qlock. In turn that requires trylocks in the reclaim path
> instead, but given it's a classic tradeoff between fast and slow path, and
> we follow the model of the inode and dentry caches.
Funny how that keeps coming up ;)
> Document our new lock order now that it has settled.
Excellent.
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Subject line has a type (insise).
>
> ---
> fs/xfs/xfs_dquot.c | 98 +++++++++++++++++++++--------------------------------
> fs/xfs/xfs_qm.c | 4 +-
> 2 files changed, 42 insertions(+), 60 deletions(-)
>
> Index: xfs/fs/xfs/xfs_dquot.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_dquot.c 2011-11-25 11:45:53.348630228 +0100
> +++ xfs/fs/xfs/xfs_dquot.c 2011-11-25 11:56:08.655296826 +0100
> @@ -39,20 +39,19 @@
> #include "xfs_qm.h"
> #include "xfs_trace.h"
>
> -
> /*
> - LOCK ORDER
> -
> - inode lock (ilock)
> - dquot hash-chain lock (hashlock)
> - xqm dquot freelist lock (freelistlock
> - mount's dquot list lock (mplistlock)
> - user dquot lock - lock ordering among dquots is based on the uid or gid
> - group dquot lock - similar to udquots. Between the two dquots, the udquot
> - has to be locked first.
> - pin lock - the dquot lock must be held to take this lock.
> - flush lock - ditto.
> -*/
> + * Lock order:
> + *
> + * ip->i_lock
> + * qh->qh_lock
> + * qi->qi_dqlist_lock
> + * dquot->q_qlock
> + * dquot->q_flush
> + * xfs_Gqm->qm_dqfrlist_lock
> + *
> + * If two dquots need to be locked the order is user before group/project,
> + * otherwise by the lowest id first, see xfs_dqlock2.
For the dquot->q_* locks, it might be worth adding the name of the
locking functions here so it is obvious when reading the code as
q_qlock and q_flush aren't used anywhere outside the locking
wrappers...
Otherwise looks sane.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2011-12-05 5:11 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-28 8:27 [PATCH 00/16] quota cleanups for Linux 3.3 Christoph Hellwig
2011-11-28 8:27 ` [PATCH 01/16] xfs: untange SYNC_WAIT and SYNC_TRYLOCK meanings for xfs_qm_dqflush Christoph Hellwig
2011-12-05 3:57 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 02/16] xfs: make sure to really flush all dquots in xfs_qm_quotacheck Christoph Hellwig
2011-12-05 3:59 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 03/16] xfs: remove xfs_qm_sync Christoph Hellwig
2011-12-05 4:09 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 04/16] xfs: remove the sync_mode argument to xfs_qm_dqflush_all Christoph Hellwig
2011-12-05 4:09 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 05/16] xfs: cleanup dquot locking helpers Christoph Hellwig
2011-12-05 4:12 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 06/16] xfs: cleanup xfs_qm_dqlookup Christoph Hellwig
2011-12-05 4:17 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 07/16] xfs: remove XFS_DQ_INACTIVE Christoph Hellwig
2011-12-05 4:23 ` Dave Chinner
2011-12-05 8:37 ` Christoph Hellwig
2011-12-06 14:43 ` Christoph Hellwig
2011-12-06 20:34 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 08/16] xfs: implement lazy removal for the dquot freelist Christoph Hellwig
2011-12-05 4:32 ` Dave Chinner
2011-12-05 8:38 ` Christoph Hellwig
2011-11-28 8:27 ` [PATCH 09/16] xfs: flatten the dquot lock ordering Christoph Hellwig
2011-12-05 5:04 ` Dave Chinner
2011-12-05 9:11 ` Christoph Hellwig
2011-12-05 9:34 ` Dave Chinner
2011-12-05 11:50 ` Christoph Hellwig
2011-12-06 0:25 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 10/16] xfs: nest qm_dqfrlist_lock insise the dquot qlock Christoph Hellwig
2011-12-05 5:10 ` Dave Chinner [this message]
2011-11-28 8:27 ` [PATCH 11/16] xfs: simplify xfs_qm_dqattach_grouphint Christoph Hellwig
2011-12-05 5:14 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 12/16] xfs: simplify xfs_qm_detach_gdquots Christoph Hellwig
2011-12-05 5:18 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 13/16] xfs: add a xfs_dqhold helper Christoph Hellwig
2011-12-05 5:22 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 14/16] xfs: merge xfs_qm_dqinit_core into the only caller Christoph Hellwig
2011-12-05 5:23 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 15/16] xfs: kill xfs_qm_idtodq Christoph Hellwig
2011-12-05 5:31 ` Dave Chinner
2011-11-28 8:27 ` [PATCH 16/16] xfs: remove XFS_QMOPT_DQSUSER Christoph Hellwig
2011-12-05 5:34 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20111205051055.GQ7046@dastard \
--to=david@fromorbit.com \
--cc=hch@infradead.org \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox