Re: [RFC Patch V1 07/30] mm: Use cpu_to_mem()/numa_mem_id() to support memoryless node

From: Tejun Heo
Date: Fri Jul 11 2014 - 12:25:04 EST


On Fri, Jul 11, 2014 at 11:19:14AM -0500, Christoph Lameter wrote:
> Yes that works. But if we want a consistent node to allocate from (and
> avoid the fallbacks) then we need this patch. I think this is up to those
> needing memoryless nodes to figure out what semantics they need.

I'm not following what you're saying. Are you saying that we need to
spread numa_mem_id() all over the place for GFP_THISNODE users on
memless nodes? There aren't that many users of GFP_THISNODE.
Wouldn't it make far more sense to just change them? Or just
introduce a new GFP flag GFP_CLOSE_OR_BUST which allows falling back
to the nearest local node for memless nodes. There's no reason to
leak this information outside allocator proper.

Thanks.

--
tejun
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