On Thu, Oct 24, 2024 at 12:23:56AM +0200, Michal Hocko wrote: > On Wed 23-10-24 15:15:20, Dongjoo Seo wrote: > > Hi Andrew, Michal, > > > > Thanks for the feedback. > > > > The issue is that CPU-less nodes can lead to incorrect NUMA stats. > > For example, NUMA_HIT may incorrectly increase for CPU-less nodes > > because the current logic doesn't account for whether a node has CPUs. > > Define incorrect > > Current semantic doesn't really care about cpu less NUMA nodes because > current means whatever is required AFIU. This is certainly a long term I agree that, in the long term, special logging for preferred_zone and a separate counter might be necessary for CPU-less nodes. > semantic. Why does this need to change and why it makes sense to > pre-existing users? This patch doesn't change existing logic; the additional logic only applies when a CPU-less node is present, so there shouldn't be concerns for pre-existing users. Currently, the NUMA stats for configurations with CPU-less nodes are incorrect, as allocations are not properly accounted for. I believe this approach improves logging accuracy with minimal impact on the memory allocation path, but I'm open to alternative solutions. This isn't the only way to address the issue—any suggestions? > > -- > Michal Hocko > SUSE Labs
