Re: [PATCH 0/3] NUMA boot hash allocation interleaving

Martin J. Bligh
2004-12-14T21:38:07Z

--On Tuesday, December 14, 2004 20:13:48 +0100 Andi Kleen <ak@suse.de> wrote:

> On Tue, Dec 14, 2004 at 10:59:50AM -0800, Martin J. Bligh wrote:
>> > NUMA systems running current Linux kernels suffer from substantial
>> > inequities in the amount of memory allocated from each NUMA node
>> > during boot. In particular, several large hashes are allocated
>> > using alloc_bootmem, and as such are allocated contiguously from
>> > a single node each.
>>
>> Yup, makes a lot of sense to me to stripe these, for the caches that
>
> I originally was a bit worried about the TLB usage, but it doesn't
> seem to be a too big issue (hopefully the benchmarks weren't too
> micro though)

Well, as long as we stripe on large page boundaries, it should be fine,
I'd think. On PPC64, it'll screw the SLB, but ... tough ;-) We can either
turn it off, or only do it on things larger than the segment size, and
just round-robin the rest, or allocate from node with most free.

>> didn't Manfred or someone (Andi?) do this before? Or did that never
>> get accepted? I know we talked about it a while back.
>
> I talked about it, but never implemented it. I am not aware of any
> other implementation of this before Brent's.

Cool, must have been my imagination ;-)

M.