Re: [PATCH] mm/memcontrol: export memcg.swap watermark via sysfs for v2 memcg

From: Johannes Weiner
Date: Wed May 24 2023 - 21:21:13 EST

On Wed, May 24, 2023 at 11:17:33AM -0700, Lars R. Damerow wrote:
> This patch is similar to commit 8e20d4b33266 ("mm/memcontrol: export
> memcg->watermark via sysfs for v2 memcg"), but exports the swap counter's
> watermark.
> We allocate jobs to our compute farm using heuristics determined by memory
> and swap usage from previous jobs. Tracking the peak swap usage for new
> jobs is important for determining when jobs are exceeding their expected
> bounds, or when our baseline metrics are getting outdated.
> Our toolset was written to use the "memory.memsw.max_usage_in_bytes" file
> in cgroups v1, and altering it to poll cgroups v2's "memory.swap.current"
> would give less accurate results as well as add complication to the code.
> Having this watermark exposed in sysfs is much preferred.
> Signed-off-by: Lars R. Damerow <lars@xxxxxxxxx>

Looks good to me.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>