From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 7664A7F4E for ; Wed, 11 Dec 2013 14:22:30 -0600 (CST) Date: Wed, 11 Dec 2013 14:22:26 -0600 From: Ben Myers Subject: Re: XFS: possible memory allocation deadlock in kmem_alloc (mode:0x250) Message-ID: <20131211202226.GH1935@sgi.com> References: <20131128091322.GC5337@easter-eggs.com> <20131128100521.GO10988@dastard> <20131203095357.GC5405@easter-eggs.com> <20131203125057.GU10988@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20131203125057.GU10988@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: Emmanuel Lacour , xfs@oss.sgi.com On Tue, Dec 03, 2013 at 11:50:57PM +1100, Dave Chinner wrote: > On Tue, Dec 03, 2013 at 10:53:58AM +0100, Emmanuel Lacour wrote: > > On Thu, Nov 28, 2013 at 09:05:21PM +1100, Dave Chinner wrote: > > > On Thu, Nov 28, 2013 at 10:13:22AM +0100, Emmanuel Lacour wrote: > > > > > > > > Dear XFS users, > > > > > > > > > > > > I run a Ceph cluster using XFS on Debian wheezy servers and Linux 3.10 > > > > (debian backports). I see the following line in our logs: > > > > > > > > XFS: possible memory allocation deadlock in kmem_alloc (mode:0x250) > > > > > > > > does this reveal a problem in my setup or may I ignore it? If it's a > > > > problem, can someone give me any hint on solving this? > > > > > > It might be, but you need to provide more information for us to be > > > able to make any intelligent comment on the message. Start here: > > > > > > http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F > > > > > > > > > The problem continue and crashed my ceph cluster again, so here is all > > the informations said in the FAQ: > > > > http://people.easter-eggs.org/~manu/xfs.log > > OK, 32GB RAM, no obvious shortage, no dirty or writeback data. > 2TB SATA drives, 32AGs, only unusual setting is 64k directory block > size. > > Yup, there's your problem: > > [4583991.478469] ceph-osd D ffff88047fc93f40 0 22951 > 1 0x00000004 > [4583991.478471] ffff88046d241140 0000000000000082 ffffffff81047e75 > ffff88046f949800 > [4583991.478475] 0000000000013f40 ffff88039eb0bfd8 ffff88039eb0bfd8 > ffff88046d241140 > [4583991.478479] 0000000000000000 00000001444d68bd ffff88046d241140 > 0000000000000005 > [4583991.478483] Call Trace: > [4583991.478487] [] ? internal_add_timer+0xd/0x28 > [4583991.478491] [] ? schedule_timeout+0xeb/0x123 > [4583991.478494] [] ? ftrace_raw_event_timer_class+0x9d/0x9d > [4583991.478498] [] ? io_schedule_timeout+0x60/0x86 > [4583991.478502] [] ? congestion_wait+0x70/0xdb > [4583991.478505] [] ? abort_exclusive_wait+0x79/0x79 > [4583991.478518] [] ? kmem_alloc+0x65/0x6f [xfs] > [4583991.478535] [] ? xfs_dir2_block_to_sf+0x5b/0x1fb [xfs] > [4583991.478550] [] ? xfs_dir2_block_sfsize+0x15b/0x16a [xfs] > [4583991.478566] [] ? xfs_dir2_block_removename+0x1c7/0x208 [xfs] > [4583991.478581] [] ? xfs_dir_removename+0xda/0x114 [xfs] > [4583991.478594] [] ? xfs_rename+0x428/0x554 [xfs] > [4583991.478606] [] ? xfs_vn_rename+0x5e/0x65 [xfs] > [4583991.478610] [] ? vfs_rename+0x224/0x35f > [4583991.478614] [] ? lookup_dcache+0x22/0x95 > [4583991.478618] [] ? SYSC_renameat+0x1c8/0x257 > [4583991.478622] [] ? __cache_free.isra.45+0x178/0x187 > [4583991.478625] [] ? SyS_mkdirat+0x2e/0xce > [4583991.478629] [] ? do_notify_resume+0x53/0x68 > [4583991.478633] [] ? system_call_fastpath+0x16/0x1b > > It'll be stuck on this: > > hdr = kmem_alloc(mp->m_dirblksize, KM_SLEEP); > > which is trying to allocate a contiguous 64k buffer to copy the > direct contents into before freeing the block and then formatting > them into the inode. The failure will be caused by memory > fragmentation, and the only way around it is to avoid the contiguous > allocation of that size. > > Which, I think, is pretty easy to do. Yup, barely smoke tested patch > below that demonstrates the fix. Beware - patch may eat babies and > ask for more. Use it at your own risk! > > I'll post it for review once it's had some testing and I know it > doesn't corrupt directories all over the place. > > > This may be related to a friend problem here: > > > > http://tracker.ceph.com/issues/6386 > > Doesn't look related, unless the OOM killer is being triggered > somehow... > > Hmmmm - there's also a good chance the the transaction commit code > has this same problem contiguous allocation problem given that it > has to allocate enough space to log an entire directory buffer. Good > guess - there's another thread stuck on exactly that: > > [4583991.476833] ceph-osd D ffff88047fc33f40 0 11072 1 0x00000004 > [4583991.476836] ffff88038b32a040 0000000000000082 ffffffff81047e75 ffff88046f946040 > [4583991.476840] 0000000000013f40 ffff88048ea11fd8 ffff88048ea11fd8 ffff88038b32a040 > [4583991.476844] 0000000000000000 00000001444d68be ffff88038b32a040 0000000000000005 > [4583991.476848] Call Trace: > [4583991.476852] [] ? internal_add_timer+0xd/0x28 > [4583991.476855] [] ? schedule_timeout+0xeb/0x123 > [4583991.476859] [] ? ftrace_raw_event_timer_class+0x9d/0x9d > [4583991.476862] [] ? io_schedule_timeout+0x60/0x86 > [4583991.476867] [] ? congestion_wait+0x70/0xdb > [4583991.476870] [] ? abort_exclusive_wait+0x79/0x79 > [4583991.476883] [] ? kmem_alloc+0x65/0x6f [xfs] > [4583991.476899] [] ? xfs_log_commit_cil+0xe8/0x3d1 [xfs] > [4583991.476904] [] ? current_kernel_time+0x9/0x30 > [4583991.476909] [] ? current_fs_time+0x27/0x2d > [4583991.476925] [] ? xfs_trans_commit+0x62/0x1cf [xfs] > [4583991.476939] [] ? xfs_create+0x41e/0x54f [xfs] > [4583991.476943] [] ? lookup_fast+0x3d/0x215 > [4583991.476954] [] ? xfs_lookup+0x88/0xee [xfs] > [4583991.476966] [] ? xfs_vn_mknod+0xb7/0x162 [xfs] > [4583991.476970] [] ? vfs_create+0x62/0x8b > [4583991.476974] [] ? lookup_dcache+0x22/0x95 > [4583991.476978] [] ? do_last+0x595/0xa16 > [4583991.476982] [] ? path_openat+0xc4/0x335 > [4583991.476985] [] ? do_filp_open+0x2a/0x6e > [4583991.476989] [] ? __alloc_fd+0xd0/0xe1 > [4583991.476993] [] ? do_sys_open+0x5c/0xe0 > [4583991.476996] [] ? system_call_fastpath+0x16/0x1b > > That one isn't so easy to fix, unfortunately. > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com > > xfs: xfs_dir2_block_to_sf temp buffer allocation fails > > From: Dave Chinner > > If we are using a large directory block size, and memory becomes > fragmented, we can get memory allocation failures trying to > kmem_alloc(64k) for a temporary buffer. However, there is not need > for a directory buffer sized allocation, as the end result ends up > in the inode literal area. This is, at most, slightly less than 2k > of space, and hence we don't need an allocation larger than that > fora temporary buffer. > > Signed-off-by: Dave Chinner D'oh, I missed this one too. If you stick 'patch' in the subject they'll have additional visibility. Looks good to me. Reviewed-by: Ben Myers _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs