From: Kiryl Shutsemau <kas@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>,
"David Hildenbrand (Arm)" <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Usama Arif <usamaarif642@gmail.com>,
Frank van der Linden <fvdl@google.com>,
Oscar Salvador <osalvador@suse.de>,
Mike Rapoport <rppt@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Zi Yan <ziy@nvidia.com>, Baoquan He <bhe@redhat.com>,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
kernel-team@meta.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
loongarch@lists.linux.dev, linux-riscv@lists.infradead.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCHv7 13/18] mm: Drop fake head checks
Date: Wed, 28 Oct 2026 14:16:58 +0000 [thread overview]
Message-ID: <auIDteFAFYTihu4_@thinkstation> (raw)
In-Reply-To: <20261028133439.GK2668804@noisy.programming.kicks-ass.net>
On Wed, Oct 28, 2026 at 02:34:39PM +0100, Peter Zijlstra wrote:
> > Only architectures with HVO matter here: x86-64, riscv and loongarch.
> > arm64 has had it disabled since 060a2c92d1b6.
>
> Per that commit, could it be re-enabled now that its no longer marked RO?
No. The problem there is the PFN change on a live vmemmap PTE, which
needs break-before-make on arm64. Dropping RO only removes the
permission change.
James Houghton is working on it with an Access Flag trick:
https://lore.kernel.org/r/20261003002123.505555-1-jthoughton@google.com
arm64 will need the writable tail too: its atomic_fetch_add_unless() is
a CAS loop.
--
Kiryl Shutsemau / Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: Kiryl Shutsemau <kas@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>,
"David Hildenbrand (Arm)" <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Usama Arif <usamaarif642@gmail.com>,
Frank van der Linden <fvdl@google.com>,
Oscar Salvador <osalvador@suse.de>,
Mike Rapoport <rppt@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Zi Yan <ziy@nvidia.com>, Baoquan He <bhe@redhat.com>,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
kernel-team@meta.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
loongarch@lists.linux.dev, linux-riscv@lists.infradead.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCHv7 13/18] mm: Drop fake head checks
Date: Wed, 28 Oct 2026 14:16:58 +0000 [thread overview]
Message-ID: <auIDteFAFYTihu4_@thinkstation> (raw)
In-Reply-To: <20261028133439.GK2668804@noisy.programming.kicks-ass.net>
On Wed, Oct 28, 2026 at 02:34:39PM +0100, Peter Zijlstra wrote:
> > Only architectures with HVO matter here: x86-64, riscv and loongarch.
> > arm64 has had it disabled since 060a2c92d1b6.
>
> Per that commit, could it be re-enabled now that its no longer marked RO?
No. The problem there is the PFN change on a live vmemmap PTE, which
needs break-before-make on arm64. Dropping RO only removes the
permission change.
James Houghton is working on it with an Access Flag trick:
https://lore.kernel.org/r/20261003002123.505555-1-jthoughton@google.com
arm64 will need the writable tail too: its atomic_fetch_add_unless() is
a CAS loop.
--
Kiryl Shutsemau / Kirill A. Shutemov
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2026-10-28 14:17 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-27 19:42 [PATCHv7 RESEND 00/17] mm: Eliminate fake head pages from vmemmap optimization Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 01/18] mm: Move MAX_FOLIO_ORDER definition to mmzone.h Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 02/18] mm: Change the interface of prep_compound_tail() Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 03/18] mm: Rename the 'compound_head' field in the 'struct page' to 'compound_info' Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 04/18] mm: Move set/clear_compound_head() next to compound_head() Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 05/18] riscv/mm: Align vmemmap to maximal folio size Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-16 16:30 ` David Hildenbrand (Arm)
2026-03-16 16:30 ` David Hildenbrand (Arm)
2026-02-27 19:42 ` [PATCHv7 06/18] LoongArch/mm: " Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-16 16:31 ` David Hildenbrand (Arm)
2026-03-16 16:31 ` David Hildenbrand (Arm)
2026-02-27 19:42 ` [PATCHv7 07/18] mm: Rework compound_head() for power-of-2 sizeof(struct page) Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 08/18] mm/sparse: Check memmap alignment for compound_info_has_mask() Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-16 16:33 ` David Hildenbrand (Arm)
2026-03-16 16:33 ` David Hildenbrand (Arm)
2026-02-27 19:42 ` [PATCHv7 09/18] mm/hugetlb: Defer vmemmap population for bootmem hugepages Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-16 16:48 ` David Hildenbrand (Arm)
2026-03-16 16:48 ` David Hildenbrand (Arm)
2026-03-17 11:28 ` Kiryl Shutsemau
2026-03-17 11:28 ` Kiryl Shutsemau
2026-03-17 12:47 ` David Hildenbrand (Arm)
2026-03-17 12:47 ` David Hildenbrand (Arm)
2026-02-27 19:42 ` [PATCHv7 10/18] mm/hugetlb: Refactor code around vmemmap_walk Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 11/18] x86/vdso: Undefine CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP for vdso32 Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-16 16:49 ` David Hildenbrand (Arm)
2026-03-16 16:49 ` David Hildenbrand (Arm)
2026-02-27 19:42 ` [PATCHv7 12/18] mm/hugetlb: Remove fake head pages Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-03-05 10:39 ` Vlastimil Babka (SUSE)
2026-03-05 10:39 ` Vlastimil Babka (SUSE)
2026-03-16 17:01 ` David Hildenbrand (Arm)
2026-03-16 17:01 ` David Hildenbrand (Arm)
2026-03-17 11:47 ` [PATCHv7.1 " Kiryl Shutsemau (Meta)
2026-03-17 11:47 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 13/18] mm: Drop fake head checks Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-10-26 17:45 ` David Hildenbrand (Arm)
2026-10-26 17:45 ` David Hildenbrand (Arm)
2026-10-26 23:25 ` Kiryl Shutsemau
2026-10-26 23:25 ` Kiryl Shutsemau
2026-10-26 23:37 ` David Hildenbrand (Arm)
2026-10-26 23:37 ` David Hildenbrand (Arm)
2026-10-27 11:00 ` Peter Zijlstra
2026-10-27 11:00 ` Peter Zijlstra
2026-10-27 12:00 ` Kiryl Shutsemau
2026-10-27 12:00 ` Kiryl Shutsemau
2026-10-27 12:05 ` David Hildenbrand (Arm)
2026-10-27 12:05 ` David Hildenbrand (Arm)
2026-10-27 12:31 ` Kiryl Shutsemau
2026-10-27 12:31 ` Kiryl Shutsemau
2026-10-27 12:47 ` Peter Zijlstra
2026-10-27 12:47 ` Peter Zijlstra
2026-10-27 12:49 ` Peter Zijlstra
2026-10-27 12:49 ` Peter Zijlstra
2026-10-27 12:58 ` David Hildenbrand (Arm)
2026-10-27 12:58 ` David Hildenbrand (Arm)
2026-10-27 13:13 ` Muchun Song
2026-10-27 13:13 ` Muchun Song
2026-10-27 13:35 ` David Hildenbrand (Arm)
2026-10-27 13:35 ` David Hildenbrand (Arm)
2026-10-27 14:03 ` Muchun Song
2026-10-27 14:03 ` Muchun Song
2026-10-27 17:51 ` Kiryl Shutsemau
2026-10-27 17:51 ` Kiryl Shutsemau
2026-10-27 20:16 ` David Hildenbrand (Arm)
2026-10-27 20:16 ` David Hildenbrand (Arm)
2026-10-28 2:38 ` Muchun Song
2026-10-28 2:38 ` Muchun Song
2026-10-28 8:06 ` Peter Zijlstra
2026-10-28 8:06 ` Peter Zijlstra
2026-10-28 12:58 ` Kiryl Shutsemau
2026-10-28 12:58 ` Kiryl Shutsemau
2026-10-28 13:34 ` Peter Zijlstra
2026-10-28 13:34 ` Peter Zijlstra
2026-10-28 14:16 ` Kiryl Shutsemau [this message]
2026-10-28 14:16 ` Kiryl Shutsemau
2026-10-28 13:04 ` Kiryl Shutsemau
2026-10-28 13:04 ` Kiryl Shutsemau
2026-10-27 12:13 ` Peter Zijlstra
2026-10-27 12:13 ` Peter Zijlstra
2026-10-27 12:22 ` Kiryl Shutsemau
2026-10-27 12:22 ` Kiryl Shutsemau
2026-10-27 12:29 ` Peter Zijlstra
2026-10-27 12:29 ` Peter Zijlstra
2026-02-27 19:42 ` [PATCHv7 14/18] hugetlb: Remove VMEMMAP_SYNCHRONIZE_RCU Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 15/18] mm/hugetlb: Remove hugetlb_optimize_vmemmap_key static key Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 16/18] mm: Remove the branch from compound_head() Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` [PATCHv7 17/18] hugetlb: Update vmemmap_dedup.rst Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-27 21:08 ` Randy Dunlap
2026-02-27 21:08 ` Randy Dunlap
2026-03-02 3:10 ` Muchun Song
2026-03-02 3:10 ` Muchun Song
2026-03-02 10:56 ` [PATCHv7.1 " Kiryl Shutsemau (Meta)
2026-03-02 10:56 ` Kiryl Shutsemau (Meta)
2026-04-30 3:25 ` patchwork-bot+linux-riscv
2026-04-30 3:25 ` patchwork-bot+linux-riscv
2026-02-27 19:42 ` [PATCHv7 18/18] mm/slab: Use compound_head() in page_slab() Kiryl Shutsemau (Meta)
2026-02-27 19:42 ` Kiryl Shutsemau (Meta)
2026-02-28 23:01 ` [PATCHv7 RESEND 00/17] mm: Eliminate fake head pages from vmemmap optimization Andrew Morton
2026-02-28 23:01 ` Andrew Morton
2026-04-30 3:25 ` patchwork-bot+linux-riscv
2026-04-30 3:25 ` patchwork-bot+linux-riscv
-- strict thread matches above, loose matches on Subject: below --
2026-02-02 15:56 [PATCHv6 " Kiryl Shutsemau
2026-02-27 19:30 ` [PATCHv7 13/18] mm: Drop fake head checks Kiryl Shutsemau (Meta)
2026-02-27 19:30 ` Kiryl Shutsemau (Meta)
2026-04-30 3:25 ` patchwork-bot+linux-riscv
2026-04-30 3:25 ` patchwork-bot+linux-riscv
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=auIDteFAFYTihu4_@thinkstation \
--to=kas@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=alex@ghiti.fr \
--cc=aou@eecs.berkeley.edu \
--cc=bhe@redhat.com \
--cc=chenhuacai@kernel.org \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=david@kernel.org \
--cc=fvdl@google.com \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@meta.com \
--cc=kernel@xen0n.name \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-riscv@lists.infradead.org \
--cc=loongarch@lists.linux.dev \
--cc=lorenzo.stoakes@oracle.com \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=muchun.song@linux.dev \
--cc=osalvador@suse.de \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=peterz@infradead.org \
--cc=rppt@kernel.org \
--cc=usamaarif642@gmail.com \
--cc=vbabka@suse.cz \
--cc=willy@infradead.org \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.