"JP Kobryn (Meta)" <[email protected]> writes: > On 3/12/26 6:40 AM, Vlastimil Babka (SUSE) wrote: >> On 3/7/26 05:55, JP Kobryn (Meta) wrote: >>> When investigating pressure on a NUMA node, there is no straightforward way >>> to determine which policies are driving allocations to it. >>> >>> Add per-policy page allocation counters as new node stat items. These >>> counters track allocations to nodes and also whether the allocations were >>> intentional or fallbacks. >>> >>> The new stats follow the existing numa hit/miss/foreign style and have the >>> following meanings: >>> >>> hit >>> - for BIND and PREFERRED_MANY, allocation succeeded on node in nodemask >>> - for other policies, allocation succeeded on intended node >>> - counted on the node of the allocation >>> miss >>> - allocation intended for other node, but happened on this one >>> - counted on other node >>> foreign >>> - allocation intended on this node, but happened on other node >>> - counted on this node >>> >>> Counters are exposed per-memcg, per-node in memory.numa_stat and globally >>> in /proc/vmstat. >>> >>> Signed-off-by: JP Kobryn (Meta) <[email protected]> >> I think I've been on of the folks on previous versions arguing >> against the >> many counters, and one of the arguments was it they can't tell the full >> story anyway (compared to e.g. tracing), but I don't think adding even more >> counters is the right solution. Seems like a number of other people >> responding to the thread are providing similar feedback. >> For example I'm still not sure how it would help me if I knew the >> hits/misses were due to a preferred vs preferred_many policy, or interleave >> vs weithed interleave? >> > > How about I change from per-policy hit/miss/foreign triplets to a single > aggregated policy triplet (i.e. just 3 new counters which account for > all policies)? They would follow the same hit/miss/foreign semantics > already proposed (visible in quoted text above). This would still > provide the otherwise missing signal of whether policy-driven > allocations to a node are intentional or fallback. > > Note that I am also planning on moving the stats off of the memcg so the > 3 new counters will be global per-node in response to similar feedback.
Emm, what's the difference between these newly added counters and the existing numa_hit/miss/foreign counters? --- Best Regards, Huang, Ying
