Am 18.09.2011 22:04, schrieb Christoph Hellwig:
On Sun, Sep 18, 2011 at 11:14:08AM +0200, Stefan Priebe - Profihost AG wrote:
at least i'm now able to reproduce the issue. I hope this will help
to investigate the issue and hopefully you can reproduce it as well.
I'm using vanilla 3.0.4 kernel + xfs as root filesystem and had
detect hanging taks with 120s set. You'll then see that the bonnie++
command get's stuck in xlog_grant_log_space while creating or
deleting files. I was using a SSD or a fast Raid 10 (24x SAS Disks)
- i was not able to reproduce it on normal SATA disks even a 20x
SATA Raid 10 didn't work.
Thanks a lot for the reproducer!
I've tried it on my laptop SSD and that didn't reproduce it yet. I'll
try it on monday on a real high end setup.
Sadly my SSD briked tonight while doing heavy testing ;-( I was not able
to reproduce it on every partition. Only on some. Sadly i was not able
to find the common point which causes this.
I've now to setup a new machine and try to reproduce it again.
What i got so far is that bonnie++ is always hanging here:
 ? radix_tree_gang_lookup_slot+0x6a/0x8d
 ? xfs_bmap_search_extents+0x56/0xb9
 ? find_get_pages+0x39/0xd8
 ? try_to_wake_up+0x1c6/0x1c6
 ? xlog_grant_push_ail+0xb7/0xbf
The traces we had in the past were difficult to check which process was
causing the lookup. So it doesn't seem to be the xlog_grant_log_space
itself it seems that it is more xfs_bmap_search_extents or