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Date: Fri, 1 Nov 2024 13:18:23 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: mengensun88@gmail.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
 alexjlzheng@tencent.com, MengEn Sun <mengensun@tencent.com>
Subject: Re: [PATCH v2] vmstat: call fold_vm_zone_numa_events() before show
 per zone NUMA event
Message-Id: <20241101131823.03e5e3e643f3dd8077f9924e@linux-foundation.org>
In-Reply-To: <1730433998-10461-1-git-send-email-mengensun@tencent.com>
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On Fri,  1 Nov 2024 12:06:38 +0800 mengensun88@gmail.com 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?