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

[Florin Iucha <florin@iucha.net>]

On Wed, Oct 31, 2007 at 02:53:25PM +0800, Fengguang Wu wrote:
> On Tue, Oct 30, 2007 at 10:52:45PM -0500, Florin Iucha wrote:
> > On Tue, Oct 30, 2007 at 07:02:42PM -0500, Florin Iucha wrote:
> > > I have added the patches and started a linux kernel compilation, and
> > > something really interesting happens.  I run the build with the
> > > equivalent of "make -j3" and in a separate console I am watching the
> > > build with 'top'.  The build consumes 98% of both CPUs.  If I stop the
> > > output in the build console with "Ctrl-S", one core goes to idle,
> > > while the other is in 50% waiting, then goes to 75% waiting.  When I
> > > resume the build with "Ctrl-Q", the build starts to use both CPUs at
> > > 98-99%.  The NFS4 use was minimal, as I did not login with Gnome, but
> > > just logged on the console.  Also, the CPU that is in 75% waiting
> > > state changes occasionally.  'Top' shows pdflush in D state, using
> > > 5-6% of CPU.
> > 
> > I forgot the traces:
> > 
> >    http://iucha.net/2.6.24-rc1/fw.1.gz
> >    http://iucha.net/2.6.24-rc1/fw.2.gz
> >    http://iucha.net/2.6.24-rc1/fw.3.gz
> 
> Sorry for the delay - I've been fixing our server today.
> 
> [  263.685691] mm/page-writeback.c 655 wb_kupdate: pdflush(248) 24235 global 4593 0 0 wc _M tw 1024 sk 0
> [  263.789648] requeue_io 301: inode 4031199 size 562 at 08:07(sda7)
> [  263.789656] requeue_io 301: inode 4031231 size 329 at 08:07(sda7)
> [  263.789660] requeue_io 301: inode 4031255 size 177 at 08:07(sda7)
> [  263.789664] requeue_io 301: inode 4031268 size 94 at 08:07(sda7)
> [  263.789667] requeue_io 301: inode 4031329 size 88 at 08:07(sda7)
> [  263.789671] requeue_io 301: inode 4031351 size 74 at 08:07(sda7)
> [  263.789674] requeue_io 301: inode 4031408 size 175 at 08:07(sda7)
> [  263.789678] requeue_io 301: inode 4031413 size 129 at 08:07(sda7)
> [  263.789681] requeue_io 301: inode 4031415 size 391 at 08:07(sda7)
> [  263.789690] mm/page-writeback.c 655 wb_kupdate: pdflush(248) 24235 global 4593 0 0 wc _M tw 1024 sk 0
> [  263.890184] requeue_io 301: inode 4031199 size 562 at 08:07(sda7)
> [  263.890191] requeue_io 301: inode 4031231 size 329 at 08:07(sda7)
> [  263.890195] requeue_io 301: inode 4031255 size 177 at 08:07(sda7)
> [  263.890198] requeue_io 301: inode 4031268 size 94 at 08:07(sda7)
> [  263.890202] requeue_io 301: inode 4031329 size 88 at 08:07(sda7)
> [  263.890205] requeue_io 301: inode 4031351 size 74 at 08:07(sda7)
> [  263.890208] requeue_io 301: inode 4031408 size 175 at 08:07(sda7)
> [  263.890212] requeue_io 301: inode 4031413 size 129 at 08:07(sda7)
> [  263.890215] requeue_io 301: inode 4031415 size 391 at 08:07(sda7)
> [  263.890223] mm/page-writeback.c 655 wb_kupdate: pdflush(248) 24235 global 4593 0 0 wc _M tw 1024 sk 0
> 
> It's about sda7, not NFSv4.
> 
> Is it a Reiserfs? We have a fresh fix for it: http://lkml.org/lkml/2007/10/23/93

Yes, it is a Reiserfs.  Incidentally it is the partition that holds
the kernel sources and build directory.  The message states that the
same bug exists in 2.6.23 but I do not see the same behavior in
2.6.23.  Anyway, I will apply the patch and see what I get.

Thanks,
florin

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

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