From: Greg KH <greg@kroah.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Alex Elder <aelder@sgi.com>, Dave Chinner <dchinner@redhat.com>,
stable@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [PATCH 4/9] [PATCH 4/9] xfs: dont serialise direct IO reads on page cache
Date: Tue, 22 Nov 2011 13:35:44 -0800 [thread overview]
Message-ID: <20111122213544.GB29127@kroah.com> (raw)
In-Reply-To: <20111122213425.GA29127@kroah.com>
On Tue, Nov 22, 2011 at 01:34:25PM -0800, Greg KH wrote:
> On Sat, Nov 19, 2011 at 01:13:40PM -0500, Christoph Hellwig wrote:
> > There is no need to grab the i_mutex of the IO lock in exclusive
> > mode if we don't need to invalidate the page cache. Taking these
> > locks on every direct IO effective serialises them as taking the IO
> > lock in exclusive mode has to wait for all shared holders to drop
> > the lock. That only happens when IO is complete, so effective it
> > prevents dispatch of concurrent direct IO reads to the same inode.
> >
> > Fix this by taking the IO lock shared to check the page cache state,
> > and only then drop it and take the IO lock exclusively if there is
> > work to be done. Hence for the normal direct IO case, no exclusive
> > locking will occur.
> >
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > Tested-by: Joern Engel <joern@logfs.org>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Alex Elder <aelder@sgi.com>
>
> What is the git commit id that matches this patch in Linus's tree?
Nevermind, I found it, 0c38a2512df272b14ef4238b476a2e4f70da1479, right?
Next time, please include the git commit id of the patch in Linus's tree
so I don't have to dig it out like I did for this series.
thanks,
greg k-h
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next prev parent reply other threads:[~2011-11-22 22:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-19 18:13 [PATCH 0/9] XFS update for 3.0-stable Christoph Hellwig
2011-11-19 18:13 ` [PATCH 1/9] [PATCH 1/9] "xfs: fix error handling for synchronous writes" Christoph Hellwig
2011-11-19 18:13 ` [PATCH 2/9] [PATCH 2/9] xfs: fix xfs_mark_inode_dirty during umount Christoph Hellwig
2011-11-19 18:13 ` [PATCH 3/9] [PATCH 3/9] xfs: fix ->write_inode return values Christoph Hellwig
2011-11-19 18:13 ` [PATCH 4/9] [PATCH 4/9] xfs: dont serialise direct IO reads on page cache Christoph Hellwig
2011-11-22 21:34 ` Greg KH
2011-11-22 21:35 ` Greg KH [this message]
2011-11-19 18:13 ` [PATCH 5/9] [PATCH 5/9] xfs: avoid direct I/O write vs buffered I/O race Christoph Hellwig
2011-11-19 18:13 ` [PATCH 6/9] [PATCH 6/9] xfs: Return -EIO when xfs_vn_getattr() failed Christoph Hellwig
2011-11-19 18:13 ` [PATCH 7/9] [PATCH 7/9] xfs: fix buffer flushing during unmount Christoph Hellwig
2011-11-19 18:13 ` [PATCH 8/9] [PATCH 8/9] xfs: Fix possible memory corruption in xfs_readlink Christoph Hellwig
2011-11-19 18:13 ` [PATCH 9/9] [PATCH 9/9] xfs: use doalloc flag in xfs_qm_dqattach_one() Christoph Hellwig
2011-11-19 18:59 ` [PATCH 0/9] XFS update for 3.0-stable Greg KH
2011-11-21 0:46 ` Dave Chinner
2011-11-21 16:05 ` Ben Myers
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