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

[Fengguang Wu <wfg@mail.ustc.edu.cn>]

On Thu, Nov 01, 2007 at 09:10:02PM -0500, Florin Iucha wrote:
> On Fri, Nov 02, 2007 at 09:33:21AM +0800, Fengguang Wu wrote:
> > > I will try that with a USB disk - I hope that won't make a difference.
> > 
> > Thank you. I guess a reiserfs on loop file would also be OK.
> > 
> > > > btw, what's the exact kernel version you are running?
> > > 
> > > I noticed it with the kernel in the $SUBJECT, as reported by 'git
> > > describe'.  I have pulled in new changesets since then.
> > 
> > And with the following patch applied?
> > 
> > ---
> >  fs/reiserfs/stree.c |    3 ---
> >  1 file changed, 3 deletions(-)
> > 
> > --- linux-2.6.24-git17.orig/fs/reiserfs/stree.c
> > +++ linux-2.6.24-git17/fs/reiserfs/stree.c
> > @@ -1458,9 +1458,6 @@ static void unmap_buffers(struct page *p
> >  				}
> >  				bh = next;
> >  			} while (bh != head);
> > -			if (PAGE_SIZE == bh->b_size) {
> > -				cancel_dirty_page(page, PAGE_CACHE_SIZE);
> > -			}
> >  		}
> >  	}
> >  }
> 
> ... and with the above patch applied.
> 
> Copying 300 MB from root (ext3) to the new file system did not trigger
> the pdflush condition.  But then I did a
>    cd $MOUNTPOINT && find . -exec md5sum {} \;
> and that brought one cpu to 75% iowait.

Immediately? Do you have the debug printk messages this time(with the
above patch)?

> I have attached my .config, if it helps.

It's really curious - I tried your .config and commands, and still
could not trigger the high iowait. I'm running 64bit Intel Core 2,
and kernel 2.6.24-rc1-git6 with the above patch.

Fengguang