linux-kernel - Re: [PATCH v5] page_alloc: allow migration of smaller hugepages during contig

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Message-ID: <aUSQin8iN78L9gKU@gourry-fedora-PF4VCD3F>
Date: Thu, 18 Dec 2025 18:38:50 -0500
From: Gregory Price <gourry@...rry.net>
To: Johannes Weiner <hannes@...xchg.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, kernel-team@...a.com,
	akpm@...ux-foundation.org, vbabka@...e.cz, surenb@...gle.com,
	mhocko@...e.com, jackmanb@...gle.com, ziy@...dia.com,
	richard.weiyang@...il.com, osalvador@...e.de, rientjes@...gle.com,
	david@...hat.com, joshua.hahnjy@...il.com, fvdl@...gle.com
Subject: Re: [PATCH v5] page_alloc: allow migration of smaller hugepages
 during contig_alloc

On Thu, Dec 18, 2025 at 02:35:19PM -0500, Johannes Weiner wrote:
> On Thu, Dec 18, 2025 at 02:08:31PM -0500, Gregory Price wrote:
> > +			page = compound_head(page);
> > +			order = compound_order(page);
> > +			if ((order >= MAX_FOLIO_ORDER) ||
> > +			    (nr_pages <= (1 << order)))
> > +				return false;
> 
> If you keep searching past it, you can step over the whole page to
> speed things up a bit:
> 
> 			i += (1 << order) - 1;

ack, good catch, added to v6

~Gregory