linux-kernel - Re: [PATCH 4/4] mm: khugepaged: set to next mm direct when mm has MMF_DISABLE_THP

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Message-ID: <x52lkv3oltbaydzgoafl2rzxka6enio2nbdvv4cqy4iv4tpwkk@tmp7iydvfbdt>
Date: Fri, 19 Dec 2025 13:31:23 +0800
From: Vernon Yang <vernon2gm@...il.com>
To: "David Hildenbrand (Red Hat)" <david@...nel.org>
Cc: akpm@...ux-foundation.org, lorenzo.stoakes@...cle.com, ziy@...dia.com, 
	baohua@...nel.org, lance.yang@...ux.dev, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, Vernon Yang <yanglincheng@...inos.cn>
Subject: Re: [PATCH 4/4] mm: khugepaged: set to next mm direct when mm has
 MMF_DISABLE_THP_COMPLETELY

On Thu, Dec 18, 2025 at 10:33:16AM +0100, David Hildenbrand (Red Hat) wrote:
> On 12/15/25 10:04, Vernon Yang wrote:
> > When an mm with the MMF_DISABLE_THP_COMPLETELY flag is detected during
> > scanning, directly set khugepaged_scan.mm_slot to the next mm_slot,
> > reduce redundant operation.
>
> That conceptually makes sense to me. How much does that safe in practice? Do
> you have some performance numbers for processes with rather large number of
> VMAs?

I also only came to this possibility through theoretical analysis and
haven't did any separate performance tests for this patch now.

If you have anything you'd like to test, please let me know, and I can
test the performance benefits.

> --
> Cheers
>
> David

--
Thanks,
Vernon