From: Harry Yoo <harry@kernel.org>
To: tao <tao.wangtao@honor.com>,
catalin.marinas@arm.com, will@kernel.org, tglx@kernel.org,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
x86@kernel.org, akpm@linux-foundation.org, david@kernel.org,
willy@infradead.org, sj@kernel.org, kees@kernel.org,
luizcap@redhat.com, zhangjiao2@cmss.chinamobile.com,
kas@kernel.org, ljs@kernel.org
Cc: hpa@zytor.com, liam@infradead.org, vbabka@kernel.org,
rppt@kernel.org, surenb@google.com, mhocko@suse.com,
jack@suse.cz, riel@surriel.com, jannh@google.com, jgg@ziepe.ca,
jhubbard@nvidia.com, peterx@redhat.com, ziy@nvidia.com,
baolin.wang@linux.alibaba.com, npache@redhat.com,
ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org,
lance.yang@linux.dev, xu.xin16@zte.com.cn,
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ying.huang@linux.alibaba.com, apopple@nvidia.com,
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shakeel.butt@linux.dev, ryncsn@gmail.com, 21cnbao@gmail.com,
jparsana@google.com, dvander@google.com, zhangji1@honor.com,
wangzicheng@honor.com
Subject: Re: [PATCH 0/15] mm: introduce ANON_VMA_LAZY for deferred anon_vma creation
Date: Wed, 3 Jun 2026 01:07:39 +0900 [thread overview]
Message-ID: <0867dac0-bc48-4aa9-891f-2066a3eff989@kernel.org> (raw)
In-Reply-To: <20260527110147.17815-1-tao.wangtao@honor.com>
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On 5/27/26 8:01 PM, tao wrote:
> Design overview
> ---------------
>
> ANON_VMA_LAZY defers anon_vma allocation until it is actually needed
> (for example during fork). VMAs that never participate in sharing can
> avoid creating anon_vma structures entirely.
>
> Before an anon_vma exists, rmap operations rely directly on VMA
> information, so no anon_vma locking is required. An anon_vma is created
> and linked only when sharing semantics are required.
It is unfortunate that the design overview doesn't cover correctness
aspect at all. VMAs are subject to change (even before being shared with
other processes), and rmap needs something that doesn't go away across
VMA merging, split, etc.
I'm not sure how the idea is supposed work correctly.
--
Cheers,
Harry / Hyeonggon
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next prev parent reply other threads:[~2026-06-02 16:08 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 11:01 [PATCH 0/15] mm: introduce ANON_VMA_LAZY for deferred anon_vma creation tao
2026-05-27 11:01 ` [PATCH 01/15] mm/rmap: introduce anon_rmap APIs for anonymous folios tao
2026-05-27 11:44 ` Lorenzo Stoakes
2026-05-28 7:47 ` wangtao
2026-05-27 11:01 ` [PATCH 02/15] mm: convert anon_vma rmap APIs to anon_rmap tao
2026-05-27 11:49 ` Lorenzo Stoakes
2026-05-28 8:55 ` wangtao
2026-05-27 11:01 ` [PATCH 03/15] mm: introduce anon_vma_tree_t for multiple anon_vma topologies tao
2026-05-27 11:56 ` Lorenzo Stoakes
2026-05-28 9:00 ` wangtao
2026-05-27 11:01 ` [PATCH 04/15] mm: switch to anon_vma_tree_t APIs in preparation for ANON_VMA_LAZY tao
2026-05-27 11:01 ` [PATCH 05/15] mm: add CONFIG_ANON_VMA_LAZY and folio helpers tao
2026-05-27 11:01 ` [PATCH 06/15] mm: add CONFIG_VMA_REF and VMA helpers tao
2026-05-27 11:01 ` [PATCH 07/15] mm: replace direct FOLIO_MAPPING_ANON usage with helpers tao
2026-05-27 11:01 ` [PATCH 08/15] mm: prepare rmap infrastructure for ANON_VMA_LAZY tao
2026-05-27 11:01 ` [PATCH 09/15] mm: implement ANON_VMA_LAZY rmap semantics tao
2026-05-27 11:01 ` [PATCH 10/15] mm: defer anon_vma creation with ANON_VMA_LAZY tao
2026-05-27 11:01 ` [PATCH 11/15] mm: handle ANON_VMA_LAZY in huge page operations tao
2026-05-27 11:01 ` [PATCH 12/15] mm: handle ANON_VMA_LAZY during migration tao
2026-05-27 11:01 ` [PATCH 13/15] mm: support setup and upgrade of ANON_VMA_LAZY folios tao
2026-05-27 11:01 ` [PATCH 14/15] mm: support merging of ANON_VMA_LAZY VMAs tao
2026-05-27 11:01 ` [PATCH 15/15] mm: enable CONFIG_ANON_VMA_LAZY on arm64 and x86_64 tao
2026-05-27 11:23 ` [PATCH 0/15] mm: introduce ANON_VMA_LAZY for deferred anon_vma creation Pedro Falcato
2026-05-28 6:45 ` wangtao
2026-05-28 7:14 ` Lorenzo Stoakes
2026-05-27 11:30 ` Lorenzo Stoakes
2026-05-28 7:11 ` wangtao
2026-05-28 7:22 ` Lorenzo Stoakes
2026-05-27 14:33 ` Lorenzo Stoakes
2026-05-28 7:57 ` wangtao
2026-05-28 8:14 ` Lorenzo Stoakes
2026-05-28 23:31 ` Barry Song
2026-05-29 2:20 ` wangzicheng
2026-05-29 6:56 ` Lorenzo Stoakes
2026-05-29 6:45 ` Lorenzo Stoakes
2026-05-29 9:41 ` wangtao
2026-05-29 12:03 ` Lorenzo Stoakes
2026-06-01 1:46 ` wangtao
2026-06-02 2:15 ` Barry Song
2026-06-02 2:46 ` Lance Yang
2026-06-02 15:37 ` Lorenzo Stoakes
2026-06-02 19:44 ` Pedro Falcato
2026-06-02 23:03 ` Barry Song
2026-06-03 7:07 ` Lorenzo Stoakes
2026-06-02 19:56 ` Harry Yoo
2026-06-02 22:27 ` Barry Song
2026-06-02 20:47 ` Lorenzo Stoakes
2026-05-29 15:07 ` Jonathan Corbet
2026-05-29 15:40 ` Lorenzo Stoakes
2026-05-30 11:28 ` Barry Song
2026-06-02 16:07 ` Harry Yoo [this message]
2026-06-03 2:59 ` wangtao
2026-06-03 3:12 ` wangtao
2026-06-03 7:54 ` Lorenzo Stoakes
2026-06-03 11:05 ` wangtao
2026-06-03 11:53 ` Lorenzo Stoakes
2026-06-04 3:50 ` wangtao
2026-06-03 20:25 ` David Hildenbrand (Arm)
2026-06-03 22:14 ` Barry Song
2026-06-04 4:03 ` wangtao
2026-06-04 4:20 ` Barry Song
2026-06-04 7:35 ` wangtao
2026-06-09 15:26 ` Suren Baghdasaryan
2026-06-09 15:49 ` David Hildenbrand (Arm)
2026-06-04 3:10 ` xu.xin16
2026-06-04 4:10 ` wangtao
2026-06-05 9:38 ` David Hildenbrand (Arm)
2026-06-05 10:07 ` Lorenzo Stoakes
2026-06-05 10:56 ` David Hildenbrand (Arm)
2026-06-04 9:40 ` Lorenzo Stoakes
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