Messages in this thread | | | Date | Tue, 30 Jun 2020 09:31:25 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline |
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* Christopher Lameter <cl@linux.com> [2020-06-29 14:58:40]:
> On Wed, 24 Jun 2020, Srikar Dronamraju wrote: > > > Currently Linux kernel with CONFIG_NUMA on a system with multiple > > possible nodes, marks node 0 as online at boot. However in practice, > > there are systems which have node 0 as memoryless and cpuless. > > Maybe add something to explain why you are not simply mapping the > existing memory to NUMA node 0 which is after all just a numbering scheme > used by the kernel and can be used arbitrarily? >
I thought Michal Hocko already gave a clear picture on why mapping is a bad idea. https://lore.kernel.org/lkml/20200316085425.GB11482@dhcp22.suse.cz/t/#u Are you suggesting that we add that as part of the changelog?
> This could be seen more as a bug in the arch code during the setup of NUMA > nodes. The two nodes are created by the firmwware / bootstrap code after > all. Just do not do it? >
- The arch/setup code in powerpc is not onlining these nodes. - Later on cpus/memory in node 0 can be onlined. - Firmware in this case Phyp is an independent code by itself.
-- Thanks and Regards Srikar Dronamraju
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