From: Matthew Wilcox <willy@infradead•org>
To: Barry Song <baohua@kernel•org>
Cc: Lorenzo Stoakes <ljs@kernel•org>,
surenb@google•com, akpm@linux-foundation•org, linux-mm@kvack•org,
david@kernel•org, liam@infradead•org, vbabka@kernel•org,
rppt@kernel•org, mhocko@suse•com, jack@suse•cz, pfalcato@suse•de,
wanglian@kylinos•cn, chentao@kylinos•cn, lianux.mm@gmail•com,
kunwu.chan@gmail•com, liyangouwen1@oppo•com, chrisl@kernel•org,
kasong@tencent•com, shikemeng@huaweicloud•com, nphamcs@gmail•com,
bhe@redhat•com, youngjun.park@lge•com,
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, Nanzhe Zhao <nzzhao@126•com>
Subject: Re: [PATCH v2 0/5] mm: reduce mmap_lock contention and improve page fault performance
Date: Mon, 18 May 2026 17:17:28 +0100 [thread overview]
Message-ID: <ags7mPK7Ong0ZsBf@casper.infradead.org> (raw)
In-Reply-To: <CAGsJ_4zqLfdWoTH9s7FFaqWWj0mESfikYgr7=GcV64qcuXrPxA@mail.gmail.com>
On Mon, May 18, 2026 at 07:25:54PM +0800, Barry Song wrote:
> We have clearly observed that the `fork()` operations of many
> popular Android apps, such as iQiyi, Baidu Tieba, and 10086,
> end up waiting on page-fault (PF) I/O when the VMA lock is
> held during I/O operations. This has already become a
> practical issue. I also believe this can lead to chained
> waiting, since the global `mmap_lock` blocks all threads that
> need to acquire it.
It's always been a terrible idea to call fork() from a multithreaded
application. For example, this question:
https://stackoverflow.com/questions/53601200/calling-fork-on-a-multithreaded-process
or this lwn thread: https://lwn.net/Articles/674660/
Do we have any insight into why these applications are doing this
horrible thing?
next prev parent reply other threads:[~2026-05-18 16:17 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-30 4:04 [PATCH v2 0/5] mm: reduce mmap_lock contention and improve page fault performance Barry Song (Xiaomi)
2026-04-30 4:04 ` [PATCH v2 1/5] mm/filemap: Retry fault by VMA lock if the lock was released for I/O Barry Song (Xiaomi)
2026-04-30 4:04 ` [PATCH v2 2/5] mm/swapin: Retry swapin " Barry Song (Xiaomi)
2026-04-30 4:04 ` [PATCH v2 3/5] mm: Move folio_lock_or_retry() and drop __folio_lock_or_retry() Barry Song (Xiaomi)
2026-04-30 4:04 ` [PATCH v2 4/5] mm: Don't retry page fault if folio is uptodate during swap-in Barry Song (Xiaomi)
2026-04-30 12:35 ` Matthew Wilcox
2026-05-01 16:11 ` Matthew Wilcox
2026-04-30 4:04 ` [PATCH v2 5/5] mm/filemap: Avoid retrying page faults on uptodate folios in filemap faults Barry Song (Xiaomi)
2026-04-30 12:37 ` [PATCH v2 0/5] mm: reduce mmap_lock contention and improve page fault performance Matthew Wilcox
2026-04-30 22:49 ` Barry Song
2026-05-01 14:56 ` Matthew Wilcox
2026-05-01 17:44 ` Barry Song
2026-05-01 17:57 ` Matthew Wilcox
2026-05-01 18:25 ` Barry Song
2026-05-01 19:39 ` Matthew Wilcox
2026-05-03 20:39 ` Barry Song
2026-05-03 13:13 ` Jan Kara
2026-05-03 19:55 ` Barry Song
2026-05-04 13:03 ` Jan Kara
2026-05-04 13:35 ` Barry Song
2026-05-04 14:15 ` Barry Song
2026-05-17 8:45 ` Barry Song
2026-05-18 9:46 ` Lorenzo Stoakes
2026-05-18 11:25 ` Barry Song
2026-05-18 16:17 ` Matthew Wilcox [this message]
2026-05-18 20:50 ` Barry Song
2026-05-18 19:56 ` Suren Baghdasaryan
2026-05-18 21:14 ` Barry Song
2026-05-19 12:45 ` Lorenzo Stoakes
2026-05-19 14:17 ` Liam R. Howlett
2026-05-19 22:01 ` Barry Song
2026-05-20 21:04 ` Matthew Wilcox
2026-05-20 21:14 ` Barry Song
2026-05-20 21:15 ` Matthew Wilcox
2026-05-20 21:35 ` David Hildenbrand (Arm)
2026-05-20 23:37 ` Barry Song
2026-05-22 15:53 ` Lorenzo Stoakes
2026-05-22 21:31 ` Barry Song
2026-05-22 2:33 ` Barry Song (Xiaomi)
2026-05-22 13:09 ` Matthew Wilcox
2026-05-22 13:36 ` Barry Song
2026-05-22 13:48 ` Barry Song
2026-05-22 15:42 ` Lorenzo Stoakes
2026-05-19 12:53 ` Lorenzo Stoakes
2026-05-19 21:18 ` Barry Song
2026-05-20 7:50 ` Lorenzo Stoakes
2026-05-20 9:07 ` Barry Song
2026-05-20 10:07 ` Lorenzo Stoakes
2026-05-20 16:20 ` Suren Baghdasaryan
2026-05-20 5:51 ` Suren Baghdasaryan
2026-05-22 15:39 ` Lorenzo Stoakes
2026-05-20 10:33 ` David Hildenbrand (Arm)
2026-05-20 12:55 ` Lorenzo Stoakes
2026-05-20 21:39 ` Yang Shi
2026-05-22 15:37 ` Lorenzo Stoakes
2026-05-19 12:43 ` Lorenzo Stoakes
2026-05-18 9:53 ` David Hildenbrand (Arm)
2026-05-19 13:42 ` Lorenzo Stoakes
2026-05-18 21:21 ` Yang Shi
2026-05-19 11:07 ` Barry Song
2026-05-19 13:34 ` Lorenzo Stoakes
2026-05-19 18:50 ` Yang Shi
2026-05-19 20:53 ` Yang Shi
2026-05-19 13:12 ` Lorenzo Stoakes
2026-05-19 13:39 ` Lorenzo Stoakes
2026-05-19 18:41 ` Yang Shi
2026-05-19 21:02 ` Yang Shi
2026-05-20 8:11 ` Lorenzo Stoakes
2026-05-01 15:52 ` Lorenzo Stoakes
2026-05-01 16:06 ` Matthew Wilcox
2026-05-01 17:09 ` Lorenzo Stoakes
2026-05-01 17:59 ` Barry Song
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