Messages in this thread |  | | | Date | Mon, 9 Nov 2009 13:27:15 +0100 | | From | Andre Przywara <> | | Subject | x86/NUMA: Reason for ignoring too small NUMA nodes? |
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Hi Andi,
while experimenting with a system with a memory-less NUMA node I stumbled upon code in the Linux kernel which ignores nodes containing less than a certain amount of RAM, obviously to fix systems with a buggy BIOS. Can you elaborate on this? What kind of incorrect entry have you seen? To correctly map the memory less node I did a patch to accept at least nodes with exactly zero bytes of memory (read: no SRAT memory entry), was this special condition also present in the buggy machines? Another comments reads: /* * Don't confuse VM with a node that doesn't have the * minimum amount of memory: */ Is that still a valid statement? How can the VM get confused by a node with already exhausted memory resources? (found in arch/x86/mm/{srat,numa}_64.c) I'd be grateful for some hints!
Thanks, Andre.
-- Andre Przywara AMD-Operating System Research Center (OSRC), Dresden, Germany Tel: +49 351 448 3567 12 ----to satisfy European Law for business letters: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen Geschaeftsfuehrer: Andrew Bowd; Thomas M. McCoy; Giuliano Meroni Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632
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