Re: [PATCH v2] vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event

From: Andrew Morton
Date: Fri Nov 01 2024 - 16:18:27 EST


On Fri, 1 Nov 2024 12:06:38 +0800 mengensun88@xxxxxxxxx wrote:

> Since 5.14-rc1, NUMA events will only be folded from per-CPU
> statistics to per zone and global statistics when the user
> actually needs it.
>
> Currently, the kernel has performs the fold operation when reading
> /proc/vmstat, but does not perform the fold operation in
> /proc/zoneinfo. This can lead to inaccuracies in the following
> statistics in zoneinfo:
> - numa_hit
> - numa_miss
> - numa_foreign
> - numa_interleave
> - numa_local
> - numa_other

Maybe we should backport this. Please tell us more about these
inaccuracies. How large are they and what is the impact upon our
users?