Message-Id: <20251127011438.6918-1-21cnbao@gmail.com>
Date: Thu, 27 Nov 2025 09:14:36 +0800
From: Barry Song <21cnbao@...il.com>
To: akpm@...ux-foundation.org,
	linux-mm@...ck.org
Cc: Barry Song <v-songbaohua@...o.com>,
	Russell King <linux@...linux.org.uk>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Huacai Chen <chenhuacai@...nel.org>,
	WANG Xuerui <kernel@...0n.name>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Paul Walmsley <pjw@...nel.org>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Alexandre Ghiti <alex@...ti.fr>,
	Alexander Gordeev <agordeev@...ux.ibm.com>,
	Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
	Heiko Carstens <hca@...ux.ibm.com>,
	Vasily Gorbik <gor@...ux.ibm.com>,
	Christian Borntraeger <borntraeger@...ux.ibm.com>,
	Sven Schnelle <svens@...ux.ibm.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Andy Lutomirski <luto@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	x86@...nel.org,
	"H . Peter Anvin" <hpa@...or.com>,
	David Hildenbrand <david@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	"Liam R . Howlett" <Liam.Howlett@...cle.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Mike Rapoport <rppt@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>,
	Matthew Wilcox <willy@...radead.org>,
	Pedro Falcato <pfalcato@...e.de>,
	Jarkko Sakkinen <jarkko@...nel.org>,
	Oscar Salvador <osalvador@...e.de>,
	Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
	Oven Liyang <liyangouwen1@...o.com>,
	Mark Rutland <mark.rutland@....com>,
	Ada Couprie Diaz <ada.coupriediaz@....com>,
	Robin Murphy <robin.murphy@....com>,
	Kristina Martšenko <kristina.martsenko@....com>,
	Kevin Brodsky <kevin.brodsky@....com>,
	Yeoreum Yun <yeoreum.yun@....com>,
	Wentao Guan <guanwentao@...ontech.com>,
	Thorsten Blum <thorsten.blum@...ux.dev>,
	Steven Rostedt <rostedt@...dmis.org>,
	Yunhui Cui <cuiyunhui@...edance.com>,
	Nam Cao <namcao@...utronix.de>,
	Chris Li <chrisl@...nel.org>,
	Kairui Song <kasong@...cent.com>,
	Kemeng Shi <shikemeng@...weicloud.com>,
	Nhat Pham <nphamcs@...il.com>,
	Baoquan He <bhe@...hat.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linuxppc-dev@...ts.ozlabs.org,
	linux-riscv@...ts.infradead.org,
	linux-s390@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: [RFC PATCH 0/2] mm: continue using per-VMA lock when retrying page faults after I/O

From: Barry Song <v-songbaohua@...o.com>

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 <linux@...linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Huacai Chen <chenhuacai@...nel.org>
Cc: WANG Xuerui <kernel@...0n.name>
Cc: Madhavan Srinivasan <maddy@...ux.ibm.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: Paul Walmsley <pjw@...nel.org>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: Alexandre Ghiti <alex@...ti.fr>
Cc: Alexander Gordeev <agordeev@...ux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
Cc: Heiko Carstens <hca@...ux.ibm.com>
Cc: Vasily Gorbik <gor@...ux.ibm.com>
Cc: Christian Borntraeger <borntraeger@...ux.ibm.com>
Cc: Sven Schnelle <svens@...ux.ibm.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: x86@...nel.org
Cc: H. Peter Anvin <hpa@...or.com>
Cc: David Hildenbrand <david@...nel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: Liam R. Howlett <Liam.Howlett@...cle.com>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: Mike Rapoport <rppt@...nel.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Pedro Falcato <pfalcato@...e.de>
Cc: Jarkko Sakkinen <jarkko@...nel.org>
Cc: Oscar Salvador <osalvador@...e.de>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
Cc: Oven Liyang <liyangouwen1@...o.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Ada Couprie Diaz <ada.coupriediaz@....com>
Cc: Robin Murphy <robin.murphy@....com>
Cc: Kristina Martšenko <kristina.martsenko@....com>
Cc: Kevin Brodsky <kevin.brodsky@....com>
Cc: Yeoreum Yun <yeoreum.yun@....com>
Cc: Wentao Guan <guanwentao@...ontech.com>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Yunhui Cui <cuiyunhui@...edance.com>
Cc: Nam Cao <namcao@...utronix.de>
Cc: Chris Li <chrisl@...nel.org>
Cc: Kairui Song <kasong@...cent.com>
Cc: Kemeng Shi <shikemeng@...weicloud.com>
Cc: Nhat Pham <nphamcs@...il.com>
Cc: Baoquan He <bhe@...hat.com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Cc: loongarch@...ts.linux.dev
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: linux-riscv@...ts.infradead.org
Cc: linux-s390@...r.kernel.org
Cc: linux-mm@...ck.org
Cc: linux-fsdevel@...r.kernel.org

-- 
2.39.3 (Apple Git-146)

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