linux-kernel - Re: [PATCH 1/3] mm/pagewalk: use min() macro instead of manual ternary

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Message-ID: <20251118165609.16c09e74@pumpkin>
Date: Tue, 18 Nov 2025 16:56:09 +0000
From: David Laight <david.laight.linux@...il.com>
To: Matthew Wilcox <willy@...radead.org>
Cc: Sahil Chandna <chandna.sahil@...il.com>, akpm@...ux-foundation.org,
 david@...hat.com, lorenzo.stoakes@...cle.com, mhocko@...e.com,
 vbabka@...e.cz, rppt@...nel.org, surenb@...gle.com, hannes@...xchg.org,
 shakeel.butt@...ux.dev, zhengqi.arch@...edance.com,
 Liam.Howlett@...cle.com, weixugc@...gle.com, axelrasmussen@...gle.com,
 yuanchu@...gle.com, yosry.ahmed@...ux.dev, nphamcs@...il.com,
 chengming.zhou@...ux.dev, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] mm/pagewalk: use min() macro instead of manual
 ternary

On Tue, 18 Nov 2025 15:18:50 +0000
Matthew Wilcox <willy@...radead.org> wrote:

> On Tue, Nov 18, 2025 at 10:45:37AM +0000, David Laight wrote:
> > On Tue, 18 Nov 2025 11:38:49 +0530
> > Sahil Chandna <chandna.sahil@...il.com> wrote:  
> > > +++ b/mm/pagewalk.c
> > > @@ -313,7 +313,7 @@ static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
> > >  				       unsigned long end)
> > >  {
> > >  	unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
> > > -	return boundary < end ? boundary : end;
> > > +	return min(boundary, end);  
> > 
> > You can remove the temporary:
> > 	return min((addr & huge_page_mask(h)) + huge_page_size(h), end);  
> 
> You can, but I'm not sure that's better.  What would be better is:
> 
> 	unsigned long boundary = (addr | ~huge_page_mask(h)) + 1;
> 	return min(boundary, end);
> 
> if you insist, we could do:
> 
> 	return min((addr | ~huge_page_mask(h)) + 1, end);

Indeed...

	David