Daniel Borkmann <daniel@xxxxxxxxxxxxx> writes: > On 10/6/22 1:36 PM, Jiri Olsa wrote: >> I recently hit 32k size limit for per-cpu map value.. it seems to be >> size limit for generic per cpu allocation, but would be great to have >> it confirmed by somebody who knows mm better ;-) > > Yes, for percpu the max is PCPU_MIN_UNIT_SIZE which is 32k, see mm/percpu.c +1756. > In many cases it's implementation specific, so it probably does not make too much > sense to state limits like 2^32, or at least it should say that its theoretical/uapi > limit and actual limits may be implementation/config specific. Yes, good point. I will just drop the 2^32 bit. Same issue was raised by Stanislav Fomichev for BPF_MAP_TYPE_HASH here: https://patchwork.kernel.org/project/netdevbpf/patch/20220713211612.84782-1-donald.hunter@xxxxxxxxx/#24936386
