From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: locking/core] locking/rwsem: Introduce rwsem_write_trylock()
Date: Wed, 09 Dec 2020 18:38:48 -0000 [thread overview]
Message-ID: <160753912849.3364.5418908733944209234.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20201207090243.GE3040@hirez.programming.kicks-ass.net>
The following commit has been merged into the locking/core branch of tip:
Commit-ID: 285c61aedf6bc5d81b37e4dc48c19012e8ff9836
Gitweb: https://git.kernel.org/tip/285c61aedf6bc5d81b37e4dc48c19012e8ff9836
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Tue, 08 Dec 2020 10:25:06 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 09 Dec 2020 17:08:47 +01:00
locking/rwsem: Introduce rwsem_write_trylock()
One copy of this logic is better than three.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201207090243.GE3040@hirez.programming.kicks-ass.net
---
kernel/locking/rwsem.c | 38 ++++++++++++++++----------------------
1 file changed, 16 insertions(+), 22 deletions(-)
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 5c0dc7e..7915456 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -285,6 +285,18 @@ static inline bool rwsem_read_trylock(struct rw_semaphore *sem)
return false;
}
+static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
+{
+ long tmp = RWSEM_UNLOCKED_VALUE;
+
+ if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, RWSEM_WRITER_LOCKED)) {
+ rwsem_set_owner(sem);
+ return true;
+ }
+
+ return false;
+}
+
/*
* Return just the real task structure pointer of the owner
*/
@@ -1395,42 +1407,24 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
*/
static inline void __down_write(struct rw_semaphore *sem)
{
- long tmp = RWSEM_UNLOCKED_VALUE;
-
- if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
- RWSEM_WRITER_LOCKED)))
+ if (unlikely(!rwsem_write_trylock(sem)))
rwsem_down_write_slowpath(sem, TASK_UNINTERRUPTIBLE);
- else
- rwsem_set_owner(sem);
}
static inline int __down_write_killable(struct rw_semaphore *sem)
{
- long tmp = RWSEM_UNLOCKED_VALUE;
-
- if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
- RWSEM_WRITER_LOCKED))) {
+ if (unlikely(!rwsem_write_trylock(sem))) {
if (IS_ERR(rwsem_down_write_slowpath(sem, TASK_KILLABLE)))
return -EINTR;
- } else {
- rwsem_set_owner(sem);
}
+
return 0;
}
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
- long tmp;
-
DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
-
- tmp = RWSEM_UNLOCKED_VALUE;
- if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
- RWSEM_WRITER_LOCKED)) {
- rwsem_set_owner(sem);
- return true;
- }
- return false;
+ return rwsem_write_trylock(sem);
}
/*
next prev parent reply other threads:[~2020-12-09 18:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 20:09 [PATCH 0/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-03 20:10 ` [PATCH 1/3] rwsem: Implement down_read_killable_nested Eric W. Biederman
2020-12-04 1:58 ` Waiman Long
2020-12-09 18:38 ` [tip: locking/core] " tip-bot2 for Eric W. Biederman
2020-12-03 20:11 ` [PATCH 2/3] rwsem: Implement down_read_interruptible Eric W. Biederman
2020-12-04 1:59 ` Waiman Long
2020-12-07 9:02 ` Peter Zijlstra
2020-12-07 15:33 ` Waiman Long
2020-12-07 16:58 ` David Laight
2020-12-07 19:02 ` Waiman Long
2020-12-08 9:12 ` David Laight
2020-12-08 12:32 ` Peter Zijlstra
2020-12-08 13:13 ` David Laight
2020-12-08 15:34 ` Waiman Long
2020-12-08 16:23 ` David Laight
2020-12-07 15:56 ` Eric W. Biederman
2020-12-08 14:52 ` Peter Zijlstra
2020-12-08 18:27 ` Eric W. Biederman
2020-12-09 18:36 ` Peter Zijlstra
2020-12-10 19:33 ` Eric W. Biederman
2020-12-11 8:16 ` Peter Zijlstra
2020-12-09 18:38 ` tip-bot2 for Peter Zijlstra [this message]
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Fold __down_{read,write}*() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Better collate rwsem_read_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] rwsem: Implement down_read_interruptible tip-bot2 for Eric W. Biederman
2020-12-03 20:12 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 16:08 ` Bernd Edlinger
2020-12-04 17:21 ` Linus Torvalds
2020-12-04 19:34 ` Eric W. Biederman
2020-12-04 20:10 ` Linus Torvalds
2020-12-04 20:30 ` Bernd Edlinger
2020-12-04 20:48 ` Linus Torvalds
2020-12-04 21:48 ` Davidlohr Bueso
2020-12-05 18:05 ` Eric W. Biederman
2020-12-07 9:15 ` Peter Zijlstra
2020-12-07 9:09 ` Peter Zijlstra
2020-12-07 18:40 ` Linus Torvalds
2020-12-08 8:34 ` [PATCH] perf: Break deadlock involving exec_update_mutex Peter Zijlstra
2020-12-08 18:37 ` Linus Torvalds
2020-12-10 18:38 ` Davidlohr Bueso
2020-12-10 19:40 ` Eric W. Biederman
2020-12-05 17:43 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 17:39 ` Eric W. Biederman
2020-12-03 22:42 ` [PATCH 0/3] " Linus Torvalds
2020-12-04 1:56 ` Waiman Long
2020-12-04 4:54 ` Davidlohr Bueso
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