linux-kernel - Re: [PATCH] mm, proc: collect percpu free pages into the free pages

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Message-ID: <ZtbERGm8CJsOwx73@tiehlicka>
Date: Tue, 3 Sep 2024 10:09:40 +0200
From: Michal Hocko <mhocko@...e.com>
To: mawupeng <mawupeng1@...wei.com>
Cc: ying.huang@...el.com, akpm@...ux-foundation.org,
	mgorman@...hsingularity.net, dmaluka@...omium.org,
	liushixin2@...wei.com, wangkefeng.wang@...wei.com,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm, proc: collect percpu free pages into the free pages

On Tue 03-09-24 09:50:48, mawupeng wrote:
> > Drain remote PCP may be not that expensive now after commit 4b23a68f9536
> > ("mm/page_alloc: protect PCP lists with a spinlock").  No IPI is needed
> > to drain the remote PCP.
> 
> This looks really great, we can think a way to drop pcp before goto slowpath
> before swap.

We currently drain after first unsuccessful direct reclaim run. Is that
insufficient? Should we do a less aggressive draining sooner? Ideally
restricted to cpus on the same NUMA node maybe? Do you have any specific
workloads that would benefit from this?
-- 
Michal Hocko
SUSE Labs