Re: Feedback on preemptible kernel patch

Daniel Phillips
2001-09-10T03:17:31Z

On September 9, 2001 11:37 pm, Robert Love wrote:
> On Sun, 2001-09-09 at 17:23, Arjan Filius wrote:
> > After my succes report i _do_ noticed something unusual:
> >
> > I'm not sure it's preempt related, but you wanted feedback :)
> >
> > Sep 9 23:08:02 sjoerd kernel: __alloc_pages: 0-order allocation failed (gfp=0x70/1).
> > Sep 9 23:08:02 sjoerd last message repeated 93 times
> > Sep 9 23:08:02 sjoerd kernel: cation failed (gfp=0x70/1).
> > Sep 9 23:08:02 sjoerd kernel: __alloc_pages: 0-order allocation failed (gfp=0x70/1).
> > Sep 9 23:08:02 sjoerd last message repeated 281 times
> >
> > This is at the very moment i make a ppp connection to internet, and
> > get/set the time with netdate (for the first time after a reboot).
> > I didn't see this a second time (yet).
> >
>
> damn, I was exciting we had solved everything :)
>
> actually, I am not confident of what could cause these results. the
> 2.4.10-pre is going through another set of changes it should not, and
> one of them concerns exactly what you are reporting.

This may not be your fault. It's a GFP_NOFS recursive allocation - this
comes either from grow_buffers or ReiserFS, probably the former. In
either case, it means we ran completely out of free pages, even though
the caller is willing to wait. Hmm. It smells like a loophole in vm
scanning.

--
Daniel