linux-kernel - Re: [PATCH 0/1] memcg/hugetlb: Adding hugeTLB counters to memory controller

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Message-ID: <ZxI0cBwXIuVUmElU@tiehlicka>
Date: Fri, 18 Oct 2024 12:12:00 +0200
From: Michal Hocko <mhocko@...e.com>
To: Joshua Hahn <joshua.hahnjy@...il.com>
Cc: hannes@...xchg.org, nphamcs@...il.com, roman.gushchin@...ux.dev,
	shakeel.butt@...ux.dev, muchun.song@...ux.dev,
	akpm@...ux-foundation.org, cgroups@...r.kernel.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org, lnyng@...a.com
Subject: Re: [PATCH 0/1] memcg/hugetlb: Adding hugeTLB counters to memory
 controller

On Thu 17-10-24 09:04:37, Joshua Hahn wrote:
> HugeTLB usage is a metric that can provide utility for monitors hoping
> to get more insight into the memory usage patterns in cgroups. It also
> helps identify if large folios are being distributed efficiently across
> workloads, so that tasks that can take most advantage of reduced TLB
> misses are prioritized.
> 
> While cgroupv2's hugeTLB controller does report this value, some users
> who wish to track hugeTLB usage might not want to take on the additional
> overhead or the features of the controller just to use the metric.
> This patch introduces hugeTLB usage in the memcg stats, mirroring the
> value in the hugeTLB controller and offering a more fine-grained
> cgroup-level breakdown of the value in /proc/meminfo.

This seems really confusing because memcg controller is not responsible
for the hugetlb memory. Could you be more specific why enabling hugetlb
controller is not really desirable when the actual per-group tracking is
needed?
 
> Signed-off-by: Joshua Hahn <joshua.hahnjy@...il.com>
> 
> Joshua Hahn (1):
>   Adding hugeTLB counters to memory controller
> 
>  include/linux/memcontrol.h | 3 +++
>  mm/hugetlb.c               | 5 +++++
>  mm/memcontrol.c            | 6 ++++++
>  3 files changed, 14 insertions(+)
> 
> -- 
> 2.43.5

-- 
Michal Hocko
SUSE Labs