Messages in this thread | | | Subject | Re: [RFC PATCH 0/10] Another Approach to Use PMEM as NUMA Node | From | Brice Goglin <> | Date | Mon, 25 Mar 2019 18:45:30 +0100 |
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Le 25/03/2019 à 17:56, Dan Williams a écrit : > > I'm generally against the concept that a "pmem" or "type" flag should > indicate anything about the expected performance of the address range. > The kernel should explicitly look to the HMAT for performance data and > not otherwise make type-based performance assumptions.
Oh sorry, I didn't mean to have the kernel use such a flag to decide of placement, but rather to expose more information to userspace to clarify what all these nodes are about when userspace will decide where to allocate things.
I understand that current NVDIMM-F are not slower than DDR and HMAT would better describe this than a flag. But I have seen so many buggy or dummy SLIT tables in the past that I wonder if we can expect HMAT to be widely available (and correct).
Is there a safe fallback in case of missing or buggy HMAT? For instance, is DDR supposed to be listed before NVDIMM (or HBM) in SRAT?
Brice
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