From: Michal Hocko <mhocko@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"David S. Miller" <davem@davemloft.net>,
Tony Luck <tony.luck@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
x86@kernel.org, linux-alpha@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org
Subject: [PATCH 0/11] introduce down_write_killable for rw_semaphore v2
Date: Fri, 1 Apr 2016 13:04:44 +0200 [thread overview]
Message-ID: <1459508695-14915-1-git-send-email-mhocko@kernel.org> (raw)
Hi,
the following patchset implements a killable variant of write lock
for rw_semaphore. My usecase is to turn as many mmap_sem write users
to use a killable variant which will be helpful for the oom_reaper
merged in 4.6-rc1 (aac453635549 ("mm, oom: introduce oom reaper")) to
asynchronously tear down the oom victim address space which requires
mmap_sem for read. This will reduce a likelihood of OOM livelocks caused
by oom victim being stuck on a lock or other resource which prevents it
to reach its exit path and release the memory. I haven't implemented the
killable variant of the read lock because I do not have any usecase for
this API.
The previous version of this series was posted [1] and the only change
since than was the rebase on top of 4.5 (with a clean merge to 4.6-rc1) and
Patch3 was updated to only check for fatal signals when the caller would
block - aka trylock will get the lock even when signals are pending to
be in sync with mutex implementation as per Peter Zijlstra.
The patchset is organized as follows.
- Patch 1 is a trivial cleanup
- Patch 2, I belive, shouldn't introduce any functional changes as per
Documentation/memory-barriers.txt.
- Patch 3 is the preparatory work and necessary infrastructure for
down_write_killable. It implements generic __down_write_killable
and prepares the write lock slow path to bail out earlier when told so
- Patch 4-1 are implementing arch specific __down_write_killable. One
patch per architecture.
- finally patch 11 implements down_write_killable and ties everything
together. I am not really an expert on lockdep so I hope I got it right.
Follow up patches to change mmap_sem write users to killable form is not
part of the series because that will be routed via mmotm tree later on.
I have tested on x86 with OOM situations with high mmap_sem contention
(basically many parallel page faults racing with many parallel mmap/munmap
tight loops) so the waiters for the write locks are routinely interrupted
by SIGKILL.
Thanks!
Shortlog says:
Michal Hocko (11):
locking, rwsem: get rid of __down_write_nested
locking, rwsem: drop explicit memory barriers
locking, rwsem: introduce basis for down_write_killable
alpha, rwsem: provide __down_write_killable
ia64, rwsem: provide __down_write_killable
s390, rwsem: provide __down_write_killable
sh, rwsem: provide __down_write_killable
sparc, rwsem: provide __down_write_killable
xtensa, rwsem: provide __down_write_killable
x86, rwsem: provide __down_write_killable
locking, rwsem: provide down_write_killable
And diffstat:
arch/alpha/include/asm/rwsem.h | 18 ++++++++++++++++--
arch/ia64/include/asm/rwsem.h | 22 ++++++++++++++++++---
arch/s390/include/asm/rwsem.h | 18 ++++++++++++++----
arch/sh/include/asm/rwsem.h | 32 +++++++++++++++----------------
arch/sparc/include/asm/rwsem.h | 14 +++++++++++---
arch/x86/include/asm/rwsem.h | 42 +++++++++++++++++++++++++----------------
arch/x86/lib/rwsem.S | 8 ++++++++
arch/xtensa/include/asm/rwsem.h | 27 ++++++++++++++------------
include/asm-generic/rwsem.h | 13 ++++++++++---
include/linux/lockdep.h | 15 +++++++++++++++
include/linux/rwsem-spinlock.h | 2 +-
include/linux/rwsem.h | 3 +++
kernel/locking/rwsem-spinlock.c | 19 ++++++++++++++++---
kernel/locking/rwsem-xadd.c | 31 ++++++++++++++++++++++++------
kernel/locking/rwsem.c | 19 +++++++++++++++++++
15 files changed, 213 insertions(+), 70 deletions(-)
---
[1] http://lkml.kernel.org/r/1456750705-7141-1-git-send-email-mhocko@kernel.org
next reply other threads:[~2016-04-01 11:05 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 11:04 Michal Hocko [this message]
2016-04-01 11:04 ` [PATCH 01/11] locking, rwsem: get rid of __down_write_nested Michal Hocko
2016-04-02 0:28 ` Davidlohr Bueso
2016-04-01 11:04 ` [PATCH 02/11] locking, rwsem: drop explicit memory barriers Michal Hocko
2016-04-02 1:17 ` Davidlohr Bueso
2016-04-04 9:03 ` Michal Hocko
2016-04-04 9:06 ` [PATCH 1/2] xtensa, rwsem: drop superfluous arch specific implementation Michal Hocko
2016-04-04 9:06 ` [PATCH 2/2] sh, " Michal Hocko
2016-04-06 9:26 ` Peter Zijlstra
2016-04-06 9:50 ` Geert Uytterhoeven
2016-04-06 10:27 ` Peter Zijlstra
2016-04-04 10:23 ` [PATCH 1/2] xtensa, " Max Filippov
2016-04-06 9:06 ` [PATCH] sparc, " Michal Hocko
2016-04-01 11:04 ` [PATCH 03/11] locking, rwsem: introduce basis for down_write_killable Michal Hocko
2016-04-02 4:41 ` Davidlohr Bueso
2016-04-04 9:17 ` Michal Hocko
2016-04-04 9:21 ` Peter Zijlstra
2016-04-07 6:58 ` Davidlohr Bueso
2016-04-07 7:38 ` Michal Hocko
2016-05-10 10:43 ` Tetsuo Handa
2016-05-10 11:53 ` Michal Hocko
2016-05-10 12:38 ` Peter Zijlstra
2016-05-10 13:57 ` Tetsuo Handa
2016-05-11 7:23 ` Michal Hocko
2016-05-11 8:28 ` Michal Hocko
2016-05-11 8:44 ` Peter Zijlstra
2016-05-11 9:04 ` Michal Hocko
2016-05-11 9:17 ` Peter Zijlstra
2016-05-11 9:31 ` Michal Hocko
2016-05-11 9:41 ` Peter Zijlstra
2016-05-11 13:59 ` Michal Hocko
2016-05-11 18:03 ` Michal Hocko
2016-05-12 11:57 ` [PATCH] locking, rwsem: Fix down_write_killable() Peter Zijlstra
2016-05-12 12:15 ` [tip:locking/rwsem] locking/rwsem: " tip-bot for Peter Zijlstra
2016-05-12 16:59 ` [PATCH] locking, rwsem: " Michal Hocko
2016-05-15 20:57 ` [tip:locking/rwsem] locking/rwsem: " tip-bot for Peter Zijlstra
2016-05-12 12:12 ` [PATCH 03/11] locking, rwsem: introduce basis for down_write_killable Peter Zijlstra
2016-05-12 12:19 ` Michal Hocko
2016-05-12 13:58 ` Peter Zijlstra
2016-05-12 19:42 ` Waiman Long
2016-05-11 8:35 ` Peter Zijlstra
2016-05-11 9:02 ` Michal Hocko
2016-04-01 11:04 ` [PATCH 04/11] alpha, rwsem: provide __down_write_killable Michal Hocko
2016-04-01 11:04 ` [PATCH 05/11] ia64, " Michal Hocko
2016-04-01 11:04 ` [PATCH 06/11] s390, " Michal Hocko
2016-04-01 11:04 ` [PATCH 07/11] sh, " Michal Hocko
2016-04-01 11:04 ` [PATCH 08/11] sparc, " Michal Hocko
2016-04-01 11:04 ` [PATCH 09/11] xtensa, " Michal Hocko
2016-04-01 11:04 ` [PATCH 10/11] x86, " Michal Hocko
2016-04-06 18:31 ` Peter Zijlstra
2016-04-01 11:04 ` [PATCH 11/11] locking, rwsem: provide down_write_killable Michal Hocko
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