From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, Liam.Howlett@oracle.com,
lorenzo.stoakes@oracle.com, david@redhat.com, vbabka@suse.cz,
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: Mon, 11 Aug 2025 16:14:58 -0700 [thread overview]
Message-ID: <CAEf4BzaRgFid5WDsNGOzE=ysc6jPcSAmB0MwRHYdtSbm-vLrWQ@mail.gmail.com> (raw)
In-Reply-To: <20250808152850.2580887-4-surenb@google.com>
On Fri, Aug 8, 2025 at 8:29 AM Suren Baghdasaryan <surenb@google.com> 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>
> ---
> fs/proc/task_mmu.c | 103 +++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 85 insertions(+), 18 deletions(-)
>
LGTM
Acked-by: Andrii Nakryiko <andrii@kernel.org>
[...]
next prev parent reply other threads:[~2025-08-11 23:15 UTC|newest]
Thread overview: 12+ 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
2025-08-11 23:14 ` Andrii Nakryiko [this message]
2025-08-13 13:50 ` Lorenzo Stoakes
[not found] ` <20250914114308.3024033-1-clm@meta.com>
2025-09-15 0:43 ` Suren Baghdasaryan
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