From: Gregory Price <gourry@gourry.net>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, akpm@linux-foundation.org, vbabka@suse.cz,
surenb@google.com, mhocko@suse.com, jackmanb@google.com,
hannes@cmpxchg.org, ziy@nvidia.com, osalvador@suse.de,
rientjes@google.com, david@redhat.com, joshua.hahnjy@gmail.com,
fvdl@google.com
Subject: Re: [PATCH v6] page_alloc: allow migration of smaller hugepages during contig_alloc
Date: Fri, 19 Dec 2025 09:26:40 -0500 [thread overview]
Message-ID: <aUVgoEiaXj94IBmW@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <20251219000800.tnpqzvcdyeqcwryt@master>
On Fri, Dec 19, 2025 at 12:08:00AM +0000, Wei Yang wrote:
> >+
> >+ page = compound_head(page);
> >+ order = compound_order(page);
>
> The order is get from head page.
>
> >+ if ((order >= MAX_FOLIO_ORDER) ||
> >+ (nr_pages <= (1 << order)))
> >+ return false;
> >+
> >+ /* No need to check the pfns for this page */
> >+ i += (1 << order) - 1;
>
> So this advance should based on "head page" instead of original page, right?
>
hm, I think the thought here was that since we're moving forward from
start of an aligned chunk, we'd never hit a non-head page - but this
may not be true.
Will think about this for a bit.
~Gregory
next prev parent reply other threads:[~2025-12-19 14:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-18 23:38 Gregory Price
2025-12-19 0:08 ` Wei Yang
2025-12-19 14:26 ` Gregory Price [this message]
2025-12-19 20:46 ` Zi Yan
2025-12-19 20:56 ` Gregory Price
2025-12-20 6:37 ` Wei Yang
2025-12-21 11:32 ` Gregory Price
2025-12-21 12:42 ` Gregory Price
2025-12-19 20:48 ` Zi Yan
2025-12-19 20:59 ` Gregory Price
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