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From: Ben Myers <bpm@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 14/15] xfs: prevent stack overflows from page cache allocation
Date: Wed, 30 Oct 2013 16:40:18 -0500	[thread overview]
Message-ID: <20131030214018.GL1935@sgi.com> (raw)
In-Reply-To: <1383045118-31107-15-git-send-email-david@fromorbit.com>

On Tue, Oct 29, 2013 at 10:11:57PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Page cache allocation doesn't always go through ->begin_write and
> hence we don't always get the opportunity to set the allocation
> context to GFP_NOFS. Failing to do this means we open up the direct
> relcaim stack to recurse into the filesystem and consume a
> significant amount of stack.
> 
> On RHEL6.4 kernels we are seeing ra_submit() and
> generic_file_splice_read() from an nfsd context recursing into the
> filesystem via the inode cache shrinker and evicting inodes. This is
> causing truncation to be run (e.g EOF block freeing) and causing
> bmap btree block merges and free space btree block splits to occur.
> These btree manipulations are occurring with the call chain already
> 30 functions deep and hence there is not enough stack space to
> complete such operations.
> 
> To avoid these specific overruns, we need to prevent the page cache
> allocation from recursing via direct reclaim. We can do that because
> the allocation functions take the allocation context from that which
> is stored in the mapping for the inode. We don't set that right now,
> so the default is GFP_HIGHUSER_MOVABLE, which is effectively a
> GFP_KERNEL context. We need it to be the equivalent of GFP_NOFS, so
> when we initialise an inode, set the mapping gfp mask appropriately.
> 
> This makes the use of AOP_FLAG_NOFS redundant from other parts of
> the XFS IO path, so get rid of it.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Applied this.

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  parent reply	other threads:[~2013-10-30 21:40 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-29 11:11 [PATCH 00/15] xfs: patches for 3.13 Dave Chinner
2013-10-29 11:11 ` [PATCH 01/15] xfs: xfs_remove deadlocks due to inverted AGF vs AGI lock ordering Dave Chinner
2013-10-30 22:39   ` Ben Myers
2013-10-30 23:15     ` Dave Chinner
2013-11-04 23:10       ` Ben Myers
2013-10-29 11:11 ` [PATCH 02/15] xfs: open code inc_inode_iversion when logging an inode Dave Chinner
2013-10-29 11:11 ` [PATCH 03/15] xfs: abstract the differences in dir2/dir3 via an ops vector Dave Chinner
2013-10-29 11:11 ` [PATCH 04/15] xfs: vectorise remaining shortform dir2 ops Dave Chinner
2013-10-29 11:11 ` [PATCH 05/15] xfs: vectorise directory data operations Dave Chinner
2013-10-29 11:11 ` [PATCH 06/15] xfs: vectorise directory data operations part 2 Dave Chinner
2013-10-29 11:11 ` [PATCH 07/15] xfs: vectorise directory leaf operations Dave Chinner
2013-10-29 11:11 ` [PATCH 08/15] xfs: vectorise DA btree operations Dave Chinner
2013-10-29 11:11 ` [PATCH 09/15] xfs: vectorise encoding/decoding directory headers Dave Chinner
2013-10-29 19:06   ` Ben Myers
2013-10-29 11:11 ` [PATCH 10/15] xfs: vectorise directory leaf operations Dave Chinner
2013-10-29 19:13   ` Ben Myers
2013-10-29 11:11 ` [PATCH 11/15] xfs: convert directory vector functions to constants Dave Chinner
2013-10-29 19:22   ` Ben Myers
2013-10-29 22:15   ` [PATCH 11/15 V2] " Dave Chinner
2013-10-30 18:09     ` Ben Myers
2013-10-29 11:11 ` [PATCH 12/15] xfs: make dir2 ftype offset pointers explicit Dave Chinner
2013-10-29 20:00   ` Ben Myers
2013-10-29 22:15     ` Dave Chinner
2013-10-30 18:51       ` Ben Myers
2013-10-29 11:11 ` [PATCH 13/15] xfs: validity check the directory block leaf entry count Dave Chinner
2013-10-29 20:43   ` Ben Myers
2013-10-29 11:11 ` [PATCH 14/15] xfs: prevent stack overflows from page cache allocation Dave Chinner
2013-10-30 10:23   ` Christoph Hellwig
2013-10-30 21:40   ` Ben Myers [this message]
2013-10-29 11:11 ` [PATCH 15/15] xfs: fix static and extern sparse warnings Dave Chinner
2013-10-29 21:12   ` Ben Myers
2013-10-30 19:22 ` [PATCH 00/15] xfs: patches for 3.13 Ben Myers

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