Messages in this thread | | | Date | Mon, 22 Aug 2022 21:34:59 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH 3/3] memcg: increase MEMCG_CHARGE_BATCH to 64 |
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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
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