Re: writeout stalls in current -git

[David Chinner <dgc@sgi.com>]

On Fri, Nov 02, 2007 at 08:22:10PM +0100, Torsten Kaiser wrote:
> [  630.000000] SysRq : Emergency Sync
> [  630.120000] Emergency Sync complete
> [  632.850000] SysRq : Show Blocked State
> [  632.850000]   task                        PC stack   pid father
> [  632.850000] pdflush       D ffff81000f091788     0   285      2
> [  632.850000]  ffff810005d4da80 0000000000000046 0000000000000800
> 0000007000000001
> [  632.850000]  ffff81000fd52400 ffffffff8022d61c ffffffff80819b00
> ffffffff80819b00
> [  632.850000]  ffffffff80815f40 ffffffff80819b00 ffff810100316f98
> 0000000000000000
> [  632.850000] Call Trace:
> [  632.850000]  [<ffffffff8022d61c>] task_rq_lock+0x4c/0x90
> [  632.850000]  [<ffffffff8022c8ea>] __wake_up_common+0x5a/0x90
> [  632.850000]  [<ffffffff805b16e7>] __down+0xa7/0x11e
> [  632.850000]  [<ffffffff8022da70>] default_wake_function+0x0/0x10
> [  632.850000]  [<ffffffff805b1365>] __down_failed+0x35/0x3a
> [  632.850000]  [<ffffffff803752ce>] xfs_buf_lock+0x3e/0x40
> [  632.850000]  [<ffffffff8037740e>] _xfs_buf_find+0x13e/0x240
> [  632.850000]  [<ffffffff8037757f>] xfs_buf_get_flags+0x6f/0x190
> [  632.850000]  [<ffffffff803776b2>] xfs_buf_read_flags+0x12/0xa0
> [  632.850000]  [<ffffffff80368824>] xfs_trans_read_buf+0x64/0x340
> [  632.850000]  [<ffffffff80352361>] xfs_itobp+0x81/0x1e0
> [  632.850000]  [<ffffffff8026b293>] write_cache_pages+0x123/0x330
> [  632.850000]  [<ffffffff80354d0e>] xfs_iflush+0xfe/0x520

That's stalled waiting on the inode cluster buffer lock. That implies
that the inode lcuser is already being written out and the inode has
been redirtied during writeout.

Does the kernel you are testing have the "flush inodes in ascending
inode number order" patches applied? If so, can you remove that
patch and see if the problem goes away?

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group