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AJvYcCU0JAn7SJOo+M+nA5KoS2WGNxbLitz1tNsqwSzIvDRbAMJ+6D39EeOkXdGLpVfiqTbGZaHYtXFiUl7AXnw=@vger.kernel.org X-Gm-Message-State: AOJu0YxPdDPozSXIImFi2agrKrzxeL6DFG0X/TPgXI+1rrDBtW34sL2D P5yAJwpTUGoD2pami56RVlejcNC+UF8siPEgS7IhjwxM/6r3VkQWWl6BiAWisEi1O1oEsPYsGiJ N/sKuMQ== X-Google-Smtp-Source: AGHT+IELDzzPgMm+39UaZJjm8Tn8NXpoMJEAAaRaanTag6m6o3qi4t1yNnmGCams/nVAxvB7CcmtNDxM1x4= X-Received: from plbm13.prod.google.com ([2002:a17:902:d18d:b0:234:b2bd:b68f]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:3bd0:b0:240:66ff:b253 with SMTP id d9443c01a7336-242c222c21bmr56641595ad.46.1754666933115; Fri, 08 Aug 2025 08:28:53 -0700 (PDT) Date: Fri, 8 Aug 2025 08:28:46 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.50.1.703.g449372360f-goog Message-ID: <20250808152850.2580887-1-surenb@google.com> Subject: [PATCH v4 0/3] execute PROCMAP_QUERY ioctl under per-vma lock From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: 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, surenb@google.com Content-Type: text/plain; charset="UTF-8" With /proc/pid/maps now being read under per-vma lock protection we can reuse parts of that code to execute PROCMAP_QUERY ioctl also without taking mmap_lock. The change is designed to reduce mmap_lock contention and prevent PROCMAP_QUERY ioctl calls from blocking address space updates. This patchset was split out of the original patchset [1] that introduced per-vma lock usage for /proc/pid/maps reading. It contains PROCMAP_QUERY tests, code refactoring patch to simplify the main change and the actual transition to per-vma lock. Changes since v3 [2] - change lock_vma_range()/unlock_vma_range() parameters, per Lorenzo Stoakes - minimize priv->lock_ctx dereferences by storing it in a local variable, per Lorenzo Stoakes - rename unlock_vma to unlock_ctx_vma, per Lorenzo Stoakes - factored out reset_lock_ctx(), per Lorenzo Stoakes - reset lock_ctx->mmap_locked inside query_vma_teardown(), per Lorenzo Stoakes - add clarifying comments in query_vma_find_by_addr() and procfs_procmap_ioctl(), per Lorenzo Stoakes - refactored error handling code inside query_vma_find_by_addr(), per Lorenzo Stoakes - add Acked-by as changes were cosmetic, per SeongJae Park [1] https://lore.kernel.org/all/20250704060727.724817-1-surenb@google.com/ [2] https://lore.kernel.org/all/20250806155905.824388-1-surenb@google.com/ Suren Baghdasaryan (3): selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified fs/proc/task_mmu: factor out proc_maps_private fields used by PROCMAP_QUERY fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks fs/proc/internal.h | 15 +- fs/proc/task_mmu.c | 184 ++++++++++++------ fs/proc/task_nommu.c | 14 +- tools/testing/selftests/proc/proc-maps-race.c | 65 +++++++ 4 files changed, 210 insertions(+), 68 deletions(-) base-commit: c2144e09b922d422346a44d72b674bf61dbd84c0 -- 2.50.1.703.g449372360f-goog