From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>, Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 02/17] writeback: update dirtied_when for synced inode to prevent livelock
Date: Thu, 12 May 2011 21:57:08 +0800 [thread overview]
Message-ID: <20110512140030.883635923@intel.com> (raw)
In-Reply-To: 20110512135706.937596128@intel.com
[-- Attachment #1: writeback-fix-sync-busyloop.patch --]
[-- Type: text/plain, Size: 3747 bytes --]
Explicitly update .dirtied_when on synced inodes, so that they are no
longer considered for writeback in the next round.
We'll do more aggressive "keep writeback as long as we wrote something"
logic in wb_writeback(). The "use LONG_MAX .nr_to_write" trick in commit
b9543dac5bbc ("writeback: avoid livelocking WB_SYNC_ALL writeback") will
no longer be enough to stop sync livelock.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
fs/fs-writeback.c | 9 +++++++++
1 file changed, 9 insertions(+)
ext3/ext4 are working fine now, however tests show that XFS may still
livelock inside the XFS routines:
[ 3581.181253] sync D ffff8800b6ca15d8 4560 4403 4392 0x00000000
[ 3581.181734] ffff88006f775bc8 0000000000000046 ffff8800b6ca12b8 00000001b6ca1938
[ 3581.182411] ffff88006f774000 00000000001d2e40 00000000001d2e40 ffff8800b6ca1280
[ 3581.183088] 00000000001d2e40 ffff88006f775fd8 00000340af111ef2 00000000001d2e40
[ 3581.183765] Call Trace:
[ 3581.184008] [<ffffffff8109be73>] ? lock_release_holdtime+0xa3/0xab
[ 3581.184392] [<ffffffff8108cc0d>] ? prepare_to_wait+0x6c/0x79
[ 3581.184756] [<ffffffff8108cc0d>] ? prepare_to_wait+0x6c/0x79
[ 3581.185120] [<ffffffff812ed520>] xfs_ioend_wait+0x87/0x9f
[ 3581.185474] [<ffffffff8108c97a>] ? wake_up_bit+0x2a/0x2a
[ 3581.185827] [<ffffffff812f742a>] xfs_sync_inode_data+0x92/0x9d
[ 3581.186198] [<ffffffff812f76e2>] xfs_inode_ag_walk+0x1a5/0x287
[ 3581.186569] [<ffffffff812f779b>] ? xfs_inode_ag_walk+0x25e/0x287
[ 3581.186946] [<ffffffff812f7398>] ? xfs_sync_worker+0x69/0x69
[ 3581.187311] [<ffffffff812e2354>] ? xfs_perag_get+0x68/0xd0
[ 3581.187669] [<ffffffff81092175>] ? local_clock+0x41/0x5a
[ 3581.188020] [<ffffffff8109be73>] ? lock_release_holdtime+0xa3/0xab
[ 3581.188403] [<ffffffff812e22ec>] ? xfs_check_sizes+0x160/0x160
[ 3581.188773] [<ffffffff812e2354>] ? xfs_perag_get+0x68/0xd0
[ 3581.189130] [<ffffffff812e236c>] ? xfs_perag_get+0x80/0xd0
[ 3581.189488] [<ffffffff812e22ec>] ? xfs_check_sizes+0x160/0x160
[ 3581.189858] [<ffffffff812f7831>] ? xfs_inode_ag_iterator+0x6d/0x8f
[ 3581.190241] [<ffffffff812f7398>] ? xfs_sync_worker+0x69/0x69
[ 3581.190606] [<ffffffff812f780b>] xfs_inode_ag_iterator+0x47/0x8f
[ 3581.190982] [<ffffffff811611f5>] ? __sync_filesystem+0x7a/0x7a
[ 3581.191352] [<ffffffff812f7877>] xfs_sync_data+0x24/0x43
[ 3581.191703] [<ffffffff812f7911>] xfs_quiesce_data+0x2c/0x88
[ 3581.192065] [<ffffffff812f5556>] xfs_fs_sync_fs+0x21/0x48
[ 3581.192419] [<ffffffff811611e1>] __sync_filesystem+0x66/0x7a
[ 3581.192783] [<ffffffff8116120b>] sync_one_sb+0x16/0x18
[ 3581.193128] [<ffffffff8113e3e3>] iterate_supers+0x72/0xce
[ 3581.193482] [<ffffffff81161140>] sync_filesystems+0x20/0x22
[ 3581.193842] [<ffffffff8116127e>] sys_sync+0x21/0x33
[ 3581.194177] [<ffffffff819016c2>] system_call_fastpath+0x16/0x1b
--- linux-next.orig/fs/fs-writeback.c 2011-05-10 09:50:07.000000000 +0800
+++ linux-next/fs/fs-writeback.c 2011-05-10 10:03:00.000000000 +0800
@@ -419,6 +419,15 @@ writeback_single_inode(struct inode *ino
spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) {
+ /*
+ * Sync livelock prevention. Each inode is tagged and synced in
+ * one shot, so we can unconditionally update its dirty time to
+ * prevent syncing it again. Note that time ordering of b_dirty
+ * list will be kept because the following code either removes
+ * the inode from b_dirty or calls redirty_tail().
+ */
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_sync)
+ inode->dirtied_when = jiffies;
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
/*
* We didn't write back all the pages. nfs_writepages()
next prev parent reply other threads:[~2011-05-12 14:04 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-12 13:57 [PATCH 00/17] writeback fixes and cleanups for 2.6.40 (v2) Wu Fengguang
2011-05-12 13:57 ` [PATCH 01/17] writeback: introduce .tagged_sync for the WB_SYNC_NONE sync stage Wu Fengguang
2011-05-12 22:40 ` Dave Chinner
2011-05-13 2:56 ` Wu Fengguang
2011-05-13 10:17 ` Christoph Hellwig
2011-05-15 23:43 ` Dave Chinner
2011-05-16 5:39 ` Wu Fengguang
2011-05-19 21:17 ` Wu Fengguang
2011-05-12 13:57 ` Wu Fengguang [this message]
2011-05-12 22:42 ` [PATCH 02/17] writeback: update dirtied_when for synced inode to prevent livelock Dave Chinner
2011-05-13 3:08 ` Wu Fengguang
2011-05-19 21:31 ` Wu Fengguang
2011-05-23 13:14 ` Jan Kara
2011-05-24 3:03 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 03/17] writeback: introduce writeback_control.inodes_cleaned Wu Fengguang
2011-05-12 22:44 ` Dave Chinner
2011-05-13 3:36 ` Wu Fengguang
2011-05-15 23:50 ` Dave Chinner
2011-05-16 10:40 ` Christoph Hellwig
2011-05-16 11:14 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 04/17] writeback: try more writeback as long as something was written Wu Fengguang
2011-05-12 13:57 ` [PATCH 05/17] writeback: the kupdate expire timestamp should be a moving target Wu Fengguang
2011-05-12 13:57 ` [PATCH 06/17] writeback: sync expired inodes first in background writeback Wu Fengguang
2011-05-12 22:55 ` Dave Chinner
2011-05-16 13:00 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 07/17] writeback: refill b_io iff empty Wu Fengguang
2011-05-12 13:57 ` [PATCH 08/17] writeback: split inode_wb_list_lock into bdi_writeback.list_lock Wu Fengguang
2011-05-12 13:57 ` [PATCH 09/17] writeback: elevate queue_io() into wb_writeback() Wu Fengguang
2011-05-12 13:57 ` [PATCH 10/17] writeback: avoid extra sync work at enqueue time Wu Fengguang
2011-05-12 13:57 ` [PATCH 11/17] writeback: add bdi_dirty_limit() kernel-doc Wu Fengguang
2011-05-12 13:57 ` [PATCH 12/17] writeback: skip balance_dirty_pages() for in-memory fs Wu Fengguang
2011-05-16 10:43 ` Christoph Hellwig
2011-05-16 10:49 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 13/17] writeback: remove writeback_control.more_io Wu Fengguang
2011-05-12 14:25 ` Minchan Kim
2011-05-12 23:04 ` Dave Chinner
2011-05-13 5:03 ` Wu Fengguang
2011-05-15 23:54 ` Dave Chinner
2011-05-12 13:57 ` [PATCH 14/17] writeback: make writeback_control.nr_to_write straight Wu Fengguang
2011-05-12 14:56 ` Jan Kara
2011-05-12 23:18 ` Dave Chinner
2011-05-13 5:28 ` Wu Fengguang
2011-05-16 0:12 ` Dave Chinner
2011-05-16 12:05 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 15/17] writeback: remove .nonblocking and .encountered_congestion Wu Fengguang
2011-05-12 13:57 ` [PATCH 16/17] writeback: trace event writeback_single_inode Wu Fengguang
2011-05-12 23:20 ` Dave Chinner
2011-05-13 5:37 ` Wu Fengguang
2011-05-16 0:14 ` Dave Chinner
2011-05-16 12:21 ` Wu Fengguang
2011-05-12 13:57 ` [PATCH 17/17] writeback: trace event writeback_queue_io Wu Fengguang
-- strict thread matches above, loose matches on Subject: below --
2011-05-06 3:08 [PATCH 00/17] writeback fixes and cleanups for 2.6.40 Wu Fengguang
2011-05-06 3:08 ` [PATCH 02/17] writeback: update dirtied_when for synced inode to prevent livelock Wu Fengguang
2011-05-06 16:33 ` Jan Kara
2011-05-10 2:14 ` Wu Fengguang
2011-05-10 12:05 ` Jan Kara
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