Re: [discuss] Memory performance problems on Tyan VX50

Andi Kleen
2006-02-01T17:16:34Z

On Wednesday 01 February 2006 18:03, Christoph Lameter wrote:
> On Wed, 1 Feb 2006, Andi Kleen wrote:
>
> > Looks like a bug. There were changes both in the page allocator and in
> > mempolicy in 2.6.16rc, so it might be related to that.
> > What does this wheremem program do exactly?
> > And what does numastat --hardware say on the machine?
> >
> > Either it's generally broken in page alloc or mempolicy somehow managed to pass in
> > a NULL zonelist.
>
> The failure is in __rmqueue. AFAIK There is no influence of mempolicy on
> that one.

I haven't followed it in all details, but it could be if the zonelist
is empty and rmqueue is the first to notice?

Or MPOL_BIND makes it just easier to trigger OOM
(maybe it would be a good idea to add some hack to prevent the oom
killer from running when the OOM comes from a non standard numa policy)

> Could we get an accurate pointer to the statement that is
> causing the NULL deref?

Andrey, can you recompile the kernel with CONFIG_DEBUG_INFO and
do a addr2line -e vmlinux <RIP from oops> ?

-Andi