From: David Hildenbrand <david@redhat.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Barry Song <21cnbao@gmail.com>
Cc: lokeshgidra@google.com, Liam.Howlett@oracle.com,
aarcange@redhat.com, akpm@linux-foundation.org,
axelrasmussen@google.com, bgeffon@google.com, jannh@google.com,
kaleshsingh@google.com, kernel-team@android.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, ngeoffray@google.com, peterx@redhat.com,
rppt@kernel.org, ryan.roberts@arm.com, selinux@vger.kernel.org,
surenb@google.com, timmurray@google.com, willy@infradead.org
Subject: Re: [PATCH v7 4/4] userfaultfd: use per-vma locks in userfaultfd operations
Date: Thu, 23 Jan 2025 18:14:50 +0100 [thread overview]
Message-ID: <7a4f8c38-13a1-4a28-b7ce-ad3bb983dd69@redhat.com> (raw)
In-Reply-To: <6aee73c6-09aa-4c2a-a28e-af9532f3f66c@lucifer.local>
>>
>> ┌────────────┐TASK_SIZE
>> │ │
>> │ │
>> │ │mmap VOLATILE
>> ┼────────────┤
>> │ │
>> │ │
>> │ │
>> │ │
>> │ │default mmap
>> │ │
>> │ │
>> └────────────┘
>>
>> VMAs in the volatile region are assigned their own volatile_mmap_lock,
>> which is independent of the mmap_lock for the non-volatile region.
>> Additionally, we ensure that no single VMA spans the boundary between
>> the volatile and non-volatile regions. This separation prevents the
>> frequent modifications of a small number of volatile VMAs from blocking
>> other operations on a large number of non-volatile VMAs.
>
> I think really overall this will be solving one can of worms by introducing
> another can of very large worms in space :P but perhaps I am missing
> details here.
Fully agreed; not a big fan :)
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-01-23 17:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 18:27 [PATCH v7 0/4] per-vma locks in userfaultfd Lokesh Gidra
2024-02-15 18:27 ` [PATCH v7 1/4] userfaultfd: move userfaultfd_ctx struct to header file Lokesh Gidra
2024-02-15 18:27 ` [PATCH v7 2/4] userfaultfd: protect mmap_changing with rw_sem in userfaulfd_ctx Lokesh Gidra
2024-02-15 18:27 ` [PATCH v7 3/4] mm: add vma_assert_locked() for !CONFIG_PER_VMA_LOCK Lokesh Gidra
2024-02-15 22:19 ` Suren Baghdasaryan
2024-02-15 18:27 ` [PATCH v7 4/4] userfaultfd: use per-vma locks in userfaultfd operations Lokesh Gidra
2025-01-23 4:14 ` Barry Song
2025-01-23 16:48 ` Lorenzo Stoakes
2025-01-23 17:07 ` Lorenzo Stoakes
2025-01-23 17:14 ` David Hildenbrand [this message]
2025-01-23 17:46 ` Suren Baghdasaryan
2025-01-23 16:52 ` Liam R. Howlett
2025-01-23 18:45 ` Lokesh Gidra
2025-01-27 22:08 ` Barry Song
2025-01-23 17:14 ` Matthew Wilcox
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