Re: pdflush stuck in D state with v2.6.24-rc1-192-gef49c32

[Florin Iucha <florin@iucha.net>]

On Tue, Oct 30, 2007 at 03:54:03PM +0800, Fengguang Wu wrote:
> On Sun, Oct 28, 2007 at 10:24:29AM -0500, Florin Iucha wrote:
> [...]
> >    [ 3687.824468] 
> >    [ 3687.824470] pdflush       D ffffffff805787c0     0   248      2
> >    [ 3687.824473]  ffff810006001d90 0000000000000046 0000000000000000 0000000000000286
> >    [ 3687.824476]  ffff8100057fc770 ffff810003062000 ffff8100057fc978 0000000106001da0
> >    [ 3687.824480]  0000000000000003 ffffffff8023b1b2 0000000000000000 0000000000000000
> >    [ 3687.824483] Call Trace:
> >    [ 3687.824488]  [<ffffffff8023b1b2>] __mod_timer+0xb8/0xca
> >    [ 3687.824492]  [<ffffffff8055c87a>] schedule_timeout+0x8d/0xb4
> >    [ 3687.824496]  [<ffffffff8023ad6c>] process_timeout+0x0/0xb
> >    [ 3687.824499]  [<ffffffff8055c79a>] io_schedule_timeout+0x28/0x33
> >    [ 3687.824503]  [<ffffffff8026bb24>] congestion_wait+0x6b/0x87
> >    [ 3687.824506]  [<ffffffff80245983>] autoremove_wake_function+0x0/0x38
> >    [ 3687.824510]  [<ffffffff8029e684>] writeback_inodes+0xcd/0xd5
> >    [ 3687.824514]  [<ffffffff80266dc4>] wb_kupdate+0xbb/0x10d
> >    [ 3687.824518]  [<ffffffff80267165>] pdflush+0x0/0x1c3
> >    [ 3687.824520]  [<ffffffff8026727d>] pdflush+0x118/0x1c3
> >    [ 3687.824523]  [<ffffffff80266d09>] wb_kupdate+0x0/0x10d
> >    [ 3687.824527]  [<ffffffff80245876>] kthread+0x49/0x77
> >    [ 3687.824530]  [<ffffffff8020c598>] child_rip+0xa/0x12
> >    [ 3687.824535]  [<ffffffff8024582d>] kthread+0x0/0x77
> >    [ 3687.824538]  [<ffffffff8020c58e>] child_rip+0x0/0x12
> >    [ 3687.824540] 
> > 
> > What could cause this?  I use NFS4 to automount the home directories
> > from a Solaris10 server, and this box found a few bugs in the NFS4
> > code (fixed in the 2.6.22 kernel).
> > 
> > I'll try running with 2.6.23 again for a few days, to see if I get the
> > pdflush stuck.  Any other ideas?
> 
> It could be triggered by the more aggressive writeback behavior - the
> new code will keep on retrying as long as there are dirty inodes pending.
> 
> Florin, would you try the attached patches against 2.6.24-git?
> They may generate big traffic of printk messages, but will help
> debug the problem.

I have updated to v2.6.24-rc1-334-g82798a1.  After using my computer
for two hours, I left the computer idle overnight.  This morning,
pdflushd is again consuming 25% of a CPU.  I will try Fengguang's
patches today.

florin

-- 
Bruce Schneier expects the Spanish Inquisition.
      http://geekz.co.uk/schneierfacts/fact/163

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