lkml.org 
[lkml]   [2018]   [May]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH v2 2/2] locking/percpu-rwsem: Mark rwsem as non-spinnable in percpu_rwsem_release()
Date
The percpu_rwsem_release() is called when the ownership of the embedded
rwsem is to be transferred to another task. The new owner, however, may
take a while to get the ownership of the lock via percpu_rwsem_acquire().
During that period, the rwsem is now marked as writer-owned with no
optimistic spinning.

Signed-off-by: Waiman Long <longman@redhat.com>
---
include/linux/percpu-rwsem.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index b1f37a8..dd37102 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -131,16 +131,16 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
lock_release(&sem->rw_sem.dep_map, 1, ip);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
if (!read)
- sem->rw_sem.owner = NULL;
-#endif
+ rwsem_set_writer_owned_nospin(&sem->rw_sem);
}

static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
+ if (!read)
+ rwsem_set_writer_owned(&sem->rw_sem, current);
}

#endif
--
1.8.3.1
\
 
 \ /
  Last update: 2018-05-14 21:34    [W:0.198 / U:0.768 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site