On Fri, Nov 02, 2007 at 08:56:55PM +0800, Fengguang Wu wrote:
> > > ---
> > > 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)?
No, but I will add them this afternoon.
> > 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.
Curious but 100% reproducible, at least on my box. What I'm going to
try is booting into the kernel with your patch and just doing the find
/ md5sum. It would be really interesting if the read-only access
triggers it.
florin
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Bruce Schneier expects the Spanish Inquisition.
http://geekz.co.uk/schneierfacts/fact/163
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