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From: Oscar Salvador <>
To: Andrew Morton <>
Cc: Dave Hansen <>,
	"Huang, Ying" <>,
	Abhishek Goel <>,
	Baolin Wang <>,,
Subject: Re: [PATCH v2] mm: Only re-generate demotion targets when a numa node changes its N_CPU state
Date: Fri, 11 Mar 2022 10:23:44 +0100	[thread overview]
Message-ID: <YisVIIGcSgi7NL8N@localhost.localdomain> (raw)
In-Reply-To: <>

On Thu, Mar 10, 2022 at 06:39:51PM -0800, Andrew Morton wrote:
> What I'm not getting here (as so often happens) is a sense of how badly
> this affects our users.  Does anyone actually hotplug frequently enough
> to care?

Well, I would not say it is critical, it just regresses the time
hotplug operations take. How bad is that? I guess it depends.
Memory hotplug operations are already slow per se, so I would say
expectations are not that high.

But it speeds up the process, that is for sure.

e.g: In a system with 144 CPUs and 2 Numa-nodes,
gets called exactly 144 times at boot time(one per every time a CPU is
brought up), where only 2 calls would suffice, so you can get an idea.

> If "yes" then I'm inclined to merge this up for 5.18 with a cc:stable. 
> Not for 5.17 because it's late and things are looking rather creaky
> already.
> And I'll add a
> Fixes: 884a6e5d1f93b ("mm/migrate: update node demotion order on hotplug events")
> which is that patch's fourth such bouquet.

Thanks Andrew!

Oscar Salvador

  reply	other threads:[~2022-03-11  9:24 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-10 12:07 [PATCH v2] mm: Only re-generate demotion targets when a numa node changes its N_CPU state Oscar Salvador
2022-03-11  1:33 ` Baolin Wang
2022-03-11  2:24 ` Huang, Ying
2022-03-11  8:39   ` Oscar Salvador
2022-03-14  1:03     ` Huang, Ying
2022-03-14 15:13       ` Oscar Salvador
2022-03-14 15:20         ` Dave Hansen
2022-03-15  6:13           ` Oscar Salvador
2022-03-15  6:31             ` Huang, Ying
2022-03-11  2:39 ` Andrew Morton
2022-03-11  9:23   ` Oscar Salvador [this message]
2022-03-11 17:10   ` Dave Hansen
2022-03-14  9:09     ` Abhishek Goel
2022-03-11  5:06 ` Huang, Ying
2022-03-11  9:17   ` Oscar Salvador
2022-03-14  3:09     ` Huang, Ying

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