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Wed, 26 Nov 2025 17:15:05 -0800 (PST) Received: from Barrys-MBP.hub ([47.72.129.29]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7c414c226f9sm22447356b3a.53.2025.11.26.17.14.44 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 26 Nov 2025 17:15:04 -0800 (PST) From: Barry Song <21cnbao@gmail.com> To: akpm@linux-foundation.org, linux-mm@kvack.org Cc: Barry Song , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Matthew Wilcox , Pedro Falcato , Jarkko Sakkinen , Oscar Salvador , Kuninori Morimoto , Oven Liyang , Mark Rutland , Ada Couprie Diaz , Robin Murphy , =?UTF-8?q?Kristina=20Mart=C5=A1enko?= , Kevin Brodsky , Yeoreum Yun , Wentao Guan , Thorsten Blum , Steven Rostedt , Yunhui Cui , Nam Cao , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [RFC PATCH 0/2] mm: continue using per-VMA lock when retrying page faults after I/O Date: Thu, 27 Nov 2025 09:14:36 +0800 Message-Id: <20251127011438.6918-1-21cnbao@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 2CEDC180006 X-Stat-Signature: pyymh594ypdgi4jz17cgapc4gsnfniyn X-Rspam-User: X-HE-Tag: 1764206106-278196 X-HE-Meta: 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 6BzuoXv/ 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 5i+cRNx6 ip0YiXMid1JzuoBqnDHsP4at2zegStciV8vIEW8s+Ausq0tRIUqhwnjIwULGbU7iyfSAJq6P4YB2Kz9VpECqC+Gbn9DlzJnjCNtrX1z4YxeGtCtUIHhCM+HJx+wBOM6+hYe2l7dLB3EOY0HJug+3c3Dj8i0UT2DpoROOSg8CyJURGVL2MZWzQcjYjVKC6qeiKYkqA/TSgMOdbIB/C65V+lsca+BxF4f4IWKlKXAJUNbZmqSS1l9ZT7dtnsbWxdfyZsgFrEAey3GXiuhjSd1OfJB6m23ygcirIWVXidAZoOxbykV2xAoLJA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Barry Song Oven observed most mmap_lock contention and priority inversion come from page fault retries after waiting for I/O completion. Oven subsequently raised the following idea: There is no need to always fall back to mmap_lock if the per-VMA lock was released only to wait for pagecache or swapcache to become ready. In this case, the retry path can continue using the per-VMA lock. This is a big win: it greatly reduces mmap_lock acquisitions. Oven Liyang (1): mm/filemap: Retry fault by VMA lock if the lock was released for I/O Barry Song (1): mm/swapin: Retry swapin by VMA lock if the lock was released for I/O arch/arm/mm/fault.c | 5 +++++ arch/arm64/mm/fault.c | 5 +++++ arch/loongarch/mm/fault.c | 4 ++++ arch/powerpc/mm/fault.c | 5 ++++- arch/riscv/mm/fault.c | 4 ++++ arch/s390/mm/fault.c | 4 ++++ arch/x86/mm/fault.c | 4 ++++ include/linux/mm_types.h | 9 +++++---- mm/filemap.c | 5 ++++- mm/memory.c | 10 ++++++++-- 10 files changed, 47 insertions(+), 8 deletions(-) Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: Huacai Chen Cc: WANG Xuerui Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Alexandre Ghiti Cc: Alexander Gordeev Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Sven Schnelle Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: x86@kernel.org Cc: H. Peter Anvin Cc: David Hildenbrand Cc: Lorenzo Stoakes Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Matthew Wilcox Cc: Pedro Falcato Cc: Jarkko Sakkinen Cc: Oscar Salvador Cc: Kuninori Morimoto Cc: Oven Liyang Cc: Mark Rutland Cc: Ada Couprie Diaz Cc: Robin Murphy Cc: Kristina Martšenko Cc: Kevin Brodsky Cc: Yeoreum Yun Cc: Wentao Guan Cc: Thorsten Blum Cc: Steven Rostedt Cc: Yunhui Cui Cc: Nam Cao Cc: Chris Li Cc: Kairui Song Cc: Kemeng Shi Cc: Nhat Pham Cc: Baoquan He Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: loongarch@lists.linux.dev Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-riscv@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org -- 2.39.3 (Apple Git-146)