Messages in this thread | | | Date | Fri, 11 Jul 2014 11:19:14 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [RFC Patch V1 07/30] mm: Use cpu_to_mem()/numa_mem_id() to support memoryless node |
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On Fri, 11 Jul 2014, Tejun Heo wrote:
> On Fri, Jul 11, 2014 at 10:58:52AM -0500, Christoph Lameter wrote: > > > But, GFP_THISNODE + numa_mem_id() is identical to numa_node_id() + > > > nearest node with memory fallback. Is there any case where the user > > > would actually want to always fail if it's on the memless node? > > > > GFP_THISNODE allocatios must fail if there is no memory available on > > the node. No fallback allowed. > > I don't know. The intention is that the caller wants something on > this node or the caller will fail or fallback ourselves, right? For > most use cases just considering the nearest memory node as "local" for > memless nodes should work and serve the intentions of the users close > enough. Whether that'd be better or we'd be better off with something > else depends on the details for sure.
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.
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