[lkml]   [2008]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: BUG: drop_pagecache_sb vs kjournald lockup
On Tue, Mar 18, 2008 at 02:43:26PM +0100, Jan Kara wrote:
> > 2.6.25-rc3, 4p ia64, ext3 root drive.
> >
> > I was running an XFS stress test on one of the XFS partitions on
> > the machine (zero load on the root ext3 drive), when the system
> > locked up in kjournald with this on the console:
> >
> > BUG: spinlock lockup on CPU#2, kjournald/2150, a000000100e022e0
> >
> <snip traces>

<snip other stuff>

> > Anyone know the reason why drop_pagecache_sb() uses such a brute-force
> > mechanism to free up clean page cache pages?
> Yes, we know that drop_pagecache_sb() has locking issues but since it
> is intended to be used for debugging purposes only, nobody cared enough
> to fix it. Completely untested patch below if you dare to try ;)

It may be intended for debuging purposes, but it does get used in
production HPC environments (a lot!). I guess I've never seen this
lockup before because SGI customers don't use ext3, but they have
complained about the system "stopping" while drop_caches is executed.
This locking ..... strategy would explain it, though.

I'll try the patch, but I can't guarantee anything - I only saw this
lockup once in about 18 hours when dropping caches every 2 seconds.


Dave Chinner
Principal Engineer
SGI Australian Software Group

 \ /
  Last update: 2008-03-19 21:33    [W:0.062 / U:2.708 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site