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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) X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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)