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From: Peter Xu <peterx@redhat.com>
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Nikita Kalyazin <kalyazin@amazon.com>,
	Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	Suren Baghdasaryan <surenb@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Vlastimil Babka <vbabka@suse.cz>,
	Muchun Song <muchun.song@linux.dev>,
	Mike Rapoport <rppt@kernel.org>, Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	James Houghton <jthoughton@google.com>,
	Michal Hocko <mhocko@suse.com>,
	David Hildenbrand <david@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Oscar Salvador <osalvador@suse.de>,
	Axel Rasmussen <axelrasmussen@google.com>,
	Ujwal Kundur <ujwal.kundur@gmail.com>
Subject: Re: [PATCH v2 1/4] mm: Introduce vm_uffd_ops API
Date: Wed, 2 Jul 2025 17:36:36 -0400	[thread overview]
Message-ID: <aGWmZKwcpLMfAN2O@x1.local> (raw)
In-Reply-To: <rsumpavnbe63jvfz7w63batked4obgnzmz4boeee6q3wiv7smi@rkok2a4vug72>

On Wed, Jul 02, 2025 at 05:24:02PM -0400, Liam R. Howlett wrote:
> That's because the entry point is from a function pointer, so [3] won't
> help at all.
> 
> It is recreating the situation that existed for the vma through the
> vm_ops in mmap, but for uffd.  And at a lower level (page tables).  I do not
> want to relive that experience.
> 
> We are not doing this.  It is for the benefit of everyone that we are
> not doing this.

Is the vma issue about "allowing vma->vm_flags to be modified anywhere"
issue?  Or is there a pointer to the issue being discussed if not?

> 
> We need to find another way.

Could you suggest something?  The minimum goal is to allow guest-memfd
support minor faults.

Thanks,

-- 
Peter Xu



  reply	other threads:[~2025-07-02 21:36 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-27 15:46 [PATCH v2 0/4] mm/userfaultfd: modulize memory types Peter Xu
2025-06-27 15:46 ` [PATCH v2 1/4] mm: Introduce vm_uffd_ops API Peter Xu
2025-06-29  8:50   ` Mike Rapoport
2025-07-02 19:30     ` Peter Xu
2025-06-30 10:15   ` Lorenzo Stoakes
2025-07-01 17:04     ` Suren Baghdasaryan
2025-07-02 15:40       ` Liam R. Howlett
2025-07-02 15:56       ` Lorenzo Stoakes
2025-07-02 17:08         ` Nikita Kalyazin
2025-07-02 17:39           ` Mike Rapoport
2025-07-02 19:46             ` Peter Xu
2025-07-03 17:48               ` Mike Rapoport
2025-07-04  9:34                 ` David Hildenbrand
2025-07-04 14:59                   ` Peter Xu
2025-07-04 19:39                     ` Liam R. Howlett
2025-09-01 16:01                       ` Nikita Kalyazin
2025-07-02 21:24           ` Liam R. Howlett
2025-07-02 21:36             ` Peter Xu [this message]
2025-07-03  2:00               ` Liam R. Howlett
2025-07-03 15:24                 ` Peter Xu
2025-07-03 16:15                   ` Lorenzo Stoakes
2025-07-03 17:39                   ` Liam R. Howlett
2025-07-02 20:24         ` Peter Xu
2025-07-03 16:32           ` Lorenzo Stoakes
2025-07-02 18:16       ` Mike Rapoport
2025-07-02 20:22         ` Peter Xu
2025-07-03 15:01           ` Suren Baghdasaryan
2025-07-03 15:45             ` Peter Xu
2025-07-03 16:01               ` Lorenzo Stoakes
2025-06-27 15:46 ` [PATCH v2 2/4] mm/shmem: Support " Peter Xu
2025-06-29  8:51   ` Mike Rapoport
2025-06-27 15:46 ` [PATCH v2 3/4] mm/hugetlb: " Peter Xu
2025-06-29  8:52   ` Mike Rapoport
2025-06-27 15:46 ` [PATCH v2 4/4] mm: Apply vm_uffd_ops API to core mm Peter Xu
2025-06-29  8:55   ` Mike Rapoport
2025-07-02 20:38     ` Peter Xu
2025-06-30 10:29 ` [PATCH v2 0/4] mm/userfaultfd: modulize memory types Lorenzo Stoakes
2025-07-01  0:15   ` Andrew Morton
2025-07-02 20:36   ` Peter Xu
2025-07-03 15:55     ` Lorenzo Stoakes
2025-07-03 16:26       ` Peter Xu
2025-07-03 16:44         ` Lorenzo Stoakes

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