Page allocation failures (was Re: WARNING: at drivers/gpu/drm/nouveau/core/core/mm.c:242)

[Peter Hurley <peter@hurleysoftware.com>]

On Tue, 2013-02-19 at 00:43 +0100, Jiri Slaby wrote:
> On 02/19/2013 12:23 AM, Marcin Slusarz wrote:
> > On Mon, Feb 18, 2013 at 11:27:43AM +0100, Jiri Slaby wrote:
> >> Hi,
> >>
> >> we have a report of WARNING from 3.7.6 in nouveau at
> >> drivers/gpu/drm/nouveau/core/core/mm.c:242 here:
> >> https://bugzilla.novell.com/show_bug.cgi?id=802347#c11
> >>
> >> There is an order 4 allocation failure in nouveau_drm_open ->
> >> nouveau_vm_create, i.e. this one failed:
> >> vm->pgt  = kcalloc(vm->lpde - vm->fpde + 1, sizeof(*vm->pgt), GFP_KERNEL);

Hi Jiri,

I had the order 4 allocation failure and nouveau crash back in November
on next-20121129. Bugzillas here:

Allocation failure:
https://bugzilla.kernel.org/show_bug.cgi?id=51301

Nouveau bug:
https://bugzilla.kernel.org/show_bug.cgi?id=51291
https://bugs.freedesktop.org/show_bug.cgi?id=58087

IMO, the 32k allocation failure is the more serious bug. Check out the
slab info from your report:

Feb 06 13:16:15 desdemona kernel: Node 0 DMA32: 13378*4kB 5026*8kB 1823*16kB
135*32kB 5*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 1*2048kB 0*4096kB = 129576kB
Feb 06 13:16:15 desdemona kernel: Node 0 Normal: 1946*4kB 831*8kB 3*16kB 1*32kB
1*64kB 1*128kB 1*256kB 1*512kB 1*1024kB 0*2048kB 0*4096kB = 16496kB

The pages are there: why did the allocation fail?

I think this is related to all that kswapd mess. In my case, the machine
really was OOM -- which made no sense. Completely out of page blocks
larger than 32k on a 10gb machine with a bunch of emacs and terminal
windows open for 3 days, just doing code, build, code, build, code,
build?

Regards,
Peter Hurley