linux-kernel - Re: Re: Re: [PATCH] mm: memcg: Use larger chunks for proactive reclaim

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Date: Fri, 2 Feb 2024 13:42:46 -0800
From: "T.J. Mercier" <tjmercier@...gle.com>
To: Michal Koutný <mkoutny@...e.com>
Cc: Efly Young <yangyifei03@...ishou.com>, hannes@...xchg.org, akpm@...ux-foundation.org, 
	android-mm@...gle.com, cgroups@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, mhocko@...nel.org, muchun.song@...ux.dev, 
	roman.gushchin@...ux.dev, shakeelb@...gle.com, yuzhao@...gle.com
Subject: Re: Re: Re: [PATCH] mm: memcg: Use larger chunks for proactive reclaim

On Fri, Feb 2, 2024 at 11:46 AM Michal Koutný <mkoutny@...e.com> wrote:
>
> On Fri, Feb 02, 2024 at 10:22:34AM -0800, "T.J. Mercier" <tjmercier@...gle.com> wrote:
> > So all of these should be more or less equivalent:
> > delta <= SWAP_CLUSTER_MAX ? delta : (delta + 3*SWAP_CLUSTER_MAX) / 4
> > max((nr_to_reclaim - nr_reclaimed) / 4, (nr_to_reclaim - nr_reclaimed) % 4)
> > (nr_to_reclaim - nr_reclaimed) / 4 + 4
> > (nr_to_reclaim - nr_reclaimed) / 4
> >
> > I was just trying to avoid putting in a 0 for the request size with the mod.
>
> The third variant would be simpler then. Modulo looks weird.
>
> Oh, and I just realized that try_to_free_mem_cgroup_pages() does
> max(nr_pages, SWAP_CLUSTER_MAX). Then I'd vote for the fourth variant +
> possible comment about harmless 0.
> (I'm sorry if this was discussed before.)
>
> Michal

Ok great, let's do that. Thanks for your input.