From: Johannes Weiner <hannes@cmpxchg.org>
To: Usama Arif <usama.arif@linux.dev>
Cc: David Hildenbrand <david@kernel.org>,
"willy@infradead.org" <willy@infradead.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Zi Yan <ziy@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
lsf-pc@lists.linux-foundation.org,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"riel@surriel.com" <riel@surriel.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Kiryl Shutsemau <kas@kernel.org>, Barry Song <baohua@kernel.org>,
Dev Jain <dev.jain@arm.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Nico Pache <npache@redhat.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Ryan Roberts <ryan.roberts@arm.com>,
Vlastimil Babka <vbabka@suse.cz>,
Lance Yang <lance.yang@linux.dev>,
Frank van der Linden <fvdl@google.com>
Subject: Re: [LSF/MM/BPF TOPIC] Beyond 2MB: Why Terabyte-Scale Machines Need 1GB Transparent Huge Pages
Date: Tue, 24 Feb 2026 14:03:12 -0500 [thread overview]
Message-ID: <aZ318PoxdAZjqnLX@cmpxchg.org> (raw)
In-Reply-To: <540c5c13-9cfb-44ea-b18f-8e4abff30a01@linux.dev>
On Thu, Feb 19, 2026 at 03:53:35PM +0000, Usama Arif wrote:
> Why 1G THP over hugetlbfs?
> ==========================
I know this isn't your intention, but one interesting aspect of
supporting PUD mapped folios natively is that it could open the door
to simplifying hugetlb as well.
We currently have all kinds of huge_vma checks scattered over the page
table code, and entirely parallel paths for unmapping etc. With native
PUD mappings, this could allow pushing the special casing out of the
virtual memory layer and into where we deal with the page objects.
You might be able to take it as far as the only thing left of hugetlb
is the reservation pool. Such that a naive application does mmap() as
per usual, and it comes down to a separate allocation policy how the
backing pages are served (buddy, CMA, boot-time reservations, ...)
Approaching it this way could help separate out the discussion on code
impact and tech debt of PUD mappings, from the allocation technique
question, which in itself is a fairly large topic.
next prev parent reply other threads:[~2026-02-24 19:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-19 15:53 Usama Arif
2026-02-19 16:00 ` David Hildenbrand (Arm)
2026-02-19 16:48 ` Johannes Weiner
2026-02-19 16:52 ` Zi Yan
2026-02-19 17:08 ` Johannes Weiner
2026-02-19 17:09 ` David Hildenbrand (Arm)
2026-02-19 17:09 ` David Hildenbrand (Arm)
2026-02-19 16:49 ` Zi Yan
2026-02-19 17:13 ` Matthew Wilcox
2026-02-19 17:28 ` Zi Yan
2026-02-19 19:02 ` Rik van Riel
2026-02-20 10:00 ` David Hildenbrand (Arm)
2026-02-24 19:03 ` Johannes Weiner [this message]
2026-02-24 19:08 ` Zi Yan
2026-02-24 20:35 ` Matthew Wilcox
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