summaryrefslogtreecommitdiffstats
path: root/kernel/locking/mutex.c
diff options
context:
space:
mode:
authorDavidlohr Bueso <dave@stgolabs.net>2015-01-30 01:14:25 -0800
committerIngo Molnar <mingo@kernel.org>2015-02-18 16:57:13 +0100
commit7a215f89a0335582292ec6f3edaa3abd570da75a (patch)
treee2f21b6e285b864eab87f5a13a1cbf91b2152eb4 /kernel/locking/mutex.c
parent49e4b2bcf7b812e985e65b6c8a0255b1520a6e7e (diff)
downloadop-kernel-dev-7a215f89a0335582292ec6f3edaa3abd570da75a.zip
op-kernel-dev-7a215f89a0335582292ec6f3edaa3abd570da75a.tar.gz
locking/rwsem: Set lock ownership ASAP
In order to optimize the spinning step, we need to set the lock owner as soon as the lock is acquired; after a successful counter cmpxchg operation, that is. This is particularly useful as rwsems need to set the owner to nil for readers, so there is a greater chance of falling out of the spinning. Currently we only set the owner much later in the game, in the more generic level -- latency can be specially bad when waiting for a node->next pointer when releasing the osq in up_write calls. As such, update the owner inside rwsem_try_write_lock (when the lock is obtained after blocking) and rwsem_try_write_lock_unqueued (when the lock is obtained while spinning). This requires creating a new internal rwsem.h header to share the owner related calls. Also cleanup some headers for mutex and rwsem. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michel Lespinasse <walken@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1422609267-15102-4-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/mutex.c')
-rw-r--r--kernel/locking/mutex.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 59cd6c3..43bf25e 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -25,7 +25,7 @@
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
-#include "mcs_spinlock.h"
+#include <linux/osq_lock.h>
/*
* In the DEBUG case we are using the "NULL fastpath" for mutexes,
OpenPOWER on IntegriCloud