summaryrefslogtreecommitdiff
path: root/kernel/locking/qspinlock_paravirt.h
diff options
context:
space:
mode:
authorWaiman Long <Waiman.Long@hpe.com>2015-12-10 23:17:46 +0300
committerIngo Molnar <mingo@kernel.org>2016-02-29 12:02:41 +0300
commiteaff0e7003cca6c2748b67ead2d4b1a8ad858fc7 (patch)
tree8b081a7e1cf7e9dadad408861193269ad03749e0 /kernel/locking/qspinlock_paravirt.h
parent920c720aa5aa3900a7f1689228fdfc2580a91e7e (diff)
downloadlinux-eaff0e7003cca6c2748b67ead2d4b1a8ad858fc7.tar.xz
locking/pvqspinlock: Move lock stealing count tracking code into pv_queued_spin_steal_lock()
This patch moves the lock stealing count tracking code into pv_queued_spin_steal_lock() instead of via a jacket function simplifying the code. Signed-off-by: Waiman Long <Waiman.Long@hpe.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Douglas Hatch <doug.hatch@hpe.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott J Norton <scott.norton@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1449778666-13593-3-git-send-email-Waiman.Long@hpe.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/qspinlock_paravirt.h')
-rw-r--r--kernel/locking/qspinlock_paravirt.h16
1 files changed, 9 insertions, 7 deletions
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 87bb235c3448..78f04a232d3a 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -55,6 +55,11 @@ struct pv_node {
};
/*
+ * Include queued spinlock statistics code
+ */
+#include "qspinlock_stat.h"
+
+/*
* By replacing the regular queued_spin_trylock() with the function below,
* it will be called once when a lock waiter enter the PV slowpath before
* being queued. By allowing one lock stealing attempt here when the pending
@@ -65,9 +70,11 @@ struct pv_node {
static inline bool pv_queued_spin_steal_lock(struct qspinlock *lock)
{
struct __qspinlock *l = (void *)lock;
+ int ret = !(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) &&
+ (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0);
- return !(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) &&
- (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0);
+ qstat_inc(qstat_pv_lock_stealing, ret);
+ return ret;
}
/*
@@ -138,11 +145,6 @@ static __always_inline int trylock_clear_pending(struct qspinlock *lock)
#endif /* _Q_PENDING_BITS == 8 */
/*
- * Include queued spinlock statistics code
- */
-#include "qspinlock_stat.h"
-
-/*
* Lock and MCS node addresses hash table for fast lookup
*
* Hashing is done on a per-cacheline basis to minimize the need to access