Re: NUMA aware slab allocator V3

Matthew Dobson
2005-05-19T19:03:26Z

Christoph Lameter wrote:
> On Wed, 18 May 2005, Christoph Lameter wrote:
>
>>Fixes to the slab allocator in 2.6.12-rc4-mm2
>>- Remove MAX_NUMNODES check
>>- use for_each_node/cpu
>>- Fix determination of INDEX_AC
>
> Rats! The whole thing with cpu online and node online is not as easy as I
> thought. There may be bugs in V3 of the numa slab allocator
> because offline cpus and offline are not properly handled. Maybe
> that also contributed to the ppc64 issues.

Running this test through the "wringer" (aka building/booting on one of our
PPC64 boxen). I'll let you know if this fixes any problems.

> The earlier patch fails if I boot an x86_64 NUMA kernel on a x86_64 single
> processor system.
>
> Here is a revised patch. Would be good if someone could review my use
> of online_cpu / online_node etc. Is there some way to bring cpus
> online and offline to test if this really works? Seems that the code in
> alloc_percpu is suspect even in the old allocator because it may have
> to allocate memory for non present cpus.

I'll look through and see what I can tell you, but I gotta run to a meeting
now. :(

-Matt