linux-kernel - Re: [PATCH mm-new v6 2/5] mm: khugepaged: refine scan progress number

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Message-ID: <85e8ded9-a9eb-4663-9c96-93af60006fb6@kernel.org>
Date: Thu, 5 Feb 2026 13:11:47 +0100
From: "David Hildenbrand (arm)" <david@...nel.org>
To: Vernon Yang <vernon2gm@...il.com>
Cc: akpm@...ux-foundation.org, lorenzo.stoakes@...cle.com, ziy@...dia.com,
 dev.jain@....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 mm-new v6 2/5] mm: khugepaged: refine scan progress number

On 2/5/26 07:08, Vernon Yang wrote:
> On Thu, Feb 5, 2026 at 5:35 AM David Hildenbrand (arm) <david@...nel.org> wrote:
>>
>> [...]
>>
>>> +     if (cur_progress) {
>>> +             if (_pte >= pte + HPAGE_PMD_NR)
>>> +                     *cur_progress = HPAGE_PMD_NR;
>>> +             else
>>> +                     *cur_progress = _pte - pte + 1;
>>
>> *cur_progress = max(_pte - pte + 1, HPAGE_PMD_NR);
> 
> I guess, your meaning is "min(_pte - pte + 1, HPAGE_PMD_NR)", not max().

Yes!

> 
>> ?
>>
>> It's still a bit nasty, though.
>>
>> Can't we just add one at the beginning of the loop and let the compiler
>> optimize that? ;)
> 
> I'm also worried that the compiler can't optimize this since the body of
> the loop is complex, as with Dev's opinion [1].

Why do we even have to optimize this? :)

Premature ... ? :)

-- 
Cheers,

David