From: Vlastimil Babka <vbabka@suse.cz>
To: Suren Baghdasaryan <surenb@google.com>, akpm@linux-foundation.org
Cc: Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com,
david@redhat.com, peterx@redhat.com, jannh@google.com,
hannes@cmpxchg.org, mhocko@kernel.org, paulmck@kernel.org,
shuah@kernel.org, adobriyan@gmail.com, brauner@kernel.org,
josef@toxicpanda.com, yebin10@huawei.com, linux@weissschuh.net,
willy@infradead.org, osalvador@suse.de, andrii@kernel.org,
ryan.roberts@arm.com, christophe.leroy@csgroup.eu,
tjmercier@google.com, kaleshsingh@google.com,
aha310510@gmail.com, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org, SeongJae Park <sj@kernel.org>
Subject: Re: [PATCH v4 3/3] fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks
Date: Fri, 8 Aug 2025 19:46:02 +0200 [thread overview]
Message-ID: <2a53f01c-db74-4298-bb9e-36b770e4fcd0@suse.cz> (raw)
In-Reply-To: <20250808152850.2580887-4-surenb@google.com>
On 8/8/25 17:28, Suren Baghdasaryan wrote:
> Utilize per-vma locks to stabilize vma after lookup without taking
> mmap_lock during PROCMAP_QUERY ioctl execution. If vma lock is
> contended, we fall back to mmap_lock but take it only momentarily
> to lock the vma and release the mmap_lock. In a very unlikely case
> of vm_refcnt overflow, this fall back path will fail and ioctl is
> done under mmap_lock protection.
>
> This change is designed to reduce mmap_lock contention and prevent
> PROCMAP_QUERY ioctl calls from blocking address space updates.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Acked-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
next prev parent reply other threads:[~2025-08-08 17:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-08 15:28 [PATCH v4 0/3] execute PROCMAP_QUERY ioctl under per-vma lock Suren Baghdasaryan
2025-08-08 15:28 ` [PATCH v4 1/3] selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified Suren Baghdasaryan
2025-08-13 13:38 ` Lorenzo Stoakes
2025-08-13 16:21 ` Suren Baghdasaryan
2025-08-13 18:53 ` Lorenzo Stoakes
2025-08-08 15:28 ` [PATCH v4 2/3] fs/proc/task_mmu: factor out proc_maps_private fields used by PROCMAP_QUERY Suren Baghdasaryan
2025-08-13 13:44 ` Lorenzo Stoakes
2025-08-08 15:28 ` [PATCH v4 3/3] fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks Suren Baghdasaryan
2025-08-08 17:46 ` Vlastimil Babka [this message]
2025-08-11 23:14 ` Andrii Nakryiko
2025-08-13 13:50 ` Lorenzo Stoakes
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