From: Davidlohr Bueso <davidlohr@hp.com>
To: Jason Low <jason.low2@hp.com>
Cc: peterz@infradead.org, mingo@kernel.org, mpatocka@redhat.com,
torvalds@linux-foundation.org, waiman.long@hp.com,
jejb@parisc-linux.org, paulmck@linux.vnet.ibm.com,
dave.anglin@bell.net, aswin@hp.com, linux-kernel@vger.kernel.org,
linux-parisc@vger.kernel.org
Subject: Re: [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER
Date: Fri, 06 Jun 2014 12:20:41 -0700 [thread overview]
Message-ID: <1402082441.14433.12.camel@buesod1.americas.hpqcorp.net> (raw)
In-Reply-To: <1402081726.6680.61.camel@j-VirtualBox>
On Fri, 2014-06-06 at 12:08 -0700, Jason Low wrote:
> And should we also change that in the optimistic spinning functions so
> that it defaults to:
>
> static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
> {
> return false;
> }
Oops Yep, afaict the last offending user.
8<----------------------------------
From: Davidlohr Bueso <davidlohr@hp.com>
Date: Fri, 6 Jun 2014 12:15:03 -0700
Subject: [PATCH v3 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER
Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER),
encapsulate the dependencies for rwsem optimistic spinning.
No logical changes here as it continues to depend on both
SMP and the XADD algorithm variant.
Acked-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
---
include/linux/rwsem.h | 4 ++--
kernel/Kconfig.locks | 4 ++++
kernel/locking/rwsem-xadd.c | 4 ++--
kernel/locking/rwsem.c | 2 +-
4 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 8d79708..accdef7 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -27,7 +27,7 @@ struct rw_semaphore {
long count;
raw_spinlock_t wait_lock;
struct list_head wait_list;
-#ifdef CONFIG_SMP
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
/*
* Write owner. Used as a speculative check to see
* if the owner is running on the cpu.
@@ -64,7 +64,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
# define __RWSEM_DEP_MAP_INIT(lockname)
#endif
-#if defined(CONFIG_SMP) && !defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
#define __RWSEM_INITIALIZER(name) \
{ RWSEM_UNLOCKED_VALUE, \
__RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index 35536d9..e4c3162 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -224,6 +224,10 @@ config MUTEX_SPIN_ON_OWNER
def_bool y
depends on SMP && !DEBUG_MUTEXES
+config RWSEM_SPIN_ON_OWNER
+ def_bool y
+ depends on SMP && RWSEM_XCHGADD_ALGORITHM
+
config ARCH_USE_QUEUE_RWLOCK
bool
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index dacc321..abe6e06 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -82,7 +82,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name,
sem->count = RWSEM_UNLOCKED_VALUE;
raw_spin_lock_init(&sem->wait_lock);
INIT_LIST_HEAD(&sem->wait_list);
-#ifdef CONFIG_SMP
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
sem->owner = NULL;
sem->osq = NULL;
#endif
@@ -262,7 +262,7 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
return false;
}
-#ifdef CONFIG_SMP
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
/*
* Try to acquire write lock before the writer has been put on wait queue.
*/
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 42f806d..e2d3bc7 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -12,7 +12,7 @@
#include <linux/atomic.h>
-#if defined(CONFIG_SMP) && defined(CONFIG_RWSEM_XCHGADD_ALGORITHM)
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
static inline void rwsem_set_owner(struct rw_semaphore *sem)
{
sem->owner = current;
--
1.8.1.4
next prev parent reply other threads:[~2014-06-06 19:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-06 15:55 [PATCH 0/2] locking/rwsem: disable optimistic spinning for PA-RISC Davidlohr Bueso
2014-06-06 15:55 ` [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER Davidlohr Bueso
2014-06-06 17:13 ` Jason Low
2014-06-06 18:12 ` Davidlohr Bueso
2014-06-06 18:48 ` Davidlohr Bueso
2014-06-06 19:08 ` Jason Low
2014-06-06 19:20 ` Davidlohr Bueso [this message]
2014-06-06 15:55 ` [PATCH 2/2] locking/rwsem: Disable optimistic spinning for PA-RISC Davidlohr Bueso
2014-06-06 16:09 ` James Bottomley
2014-06-06 17:11 ` Peter Zijlstra
2014-06-06 17:19 ` Chris Metcalf
2014-06-06 17:22 ` Linus Torvalds
2014-06-06 17:53 ` Peter Zijlstra
2014-06-06 17:57 ` James Bottomley
2014-06-06 17:58 ` James Bottomley
2014-06-06 18:01 ` Peter Zijlstra
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