From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============6148794484208155962==" MIME-Version: 1.0 From: Michal Hocko To: lkp@lists.01.org Subject: Re: [PATCH 3/3] memcg: increase MEMCG_CHARGE_BATCH to 64 Date: Mon, 22 Aug 2022 21:34:59 +0200 Message-ID: In-Reply-To: List-Id: --===============6148794484208155962== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Mon 22-08-22 11:37:30, Roman Gushchin wrote: [...] > I wonder only if we want to make it configurable (Idk a sysctl or maybe > a config option) and close the topic. I do not think this is a good idea. We have other examples where we have outsourced internal tunning to the userspace and it has mostly proven impractical and long term more problematic than useful (e.g. lowmem_reserve_ratio, percpu_pagelist_high_fraction, swappiness just to name some that come to my mind). I have seen more often these to be used incorrectly than useful. In this case, I guess we should consider either moving to per memcg charge batching and see whether the pcp overhead x memcg_count is worth that or some automagic tuning of the batch size depending on how effectively the batch is used. Certainly a lot of room for experimenting. -- = Michal Hocko SUSE Labs --===============6148794484208155962==--