lkml.org 
[lkml]   [2016]   [Feb]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:locking/core] locking/pvqspinlock: Move lock stealing count tracking code into pv_queued_spin_steal_lock()
Commit-ID:  eaff0e7003cca6c2748b67ead2d4b1a8ad858fc7
Gitweb: http://git.kernel.org/tip/eaff0e7003cca6c2748b67ead2d4b1a8ad858fc7
Author: Waiman Long <Waiman.Long@hpe.com>
AuthorDate: Thu, 10 Dec 2015 15:17:46 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 29 Feb 2016 10:02:41 +0100

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>
---
kernel/locking/qspinlock_paravirt.h | 16 +++++++++-------
kernel/locking/qspinlock_stat.h | 13 -------------
2 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 87bb235..78f04a2 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
diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h
index 640dcec..869988d 100644
--- a/kernel/locking/qspinlock_stat.h
+++ b/kernel/locking/qspinlock_stat.h
@@ -279,19 +279,6 @@ static inline void __pv_wait(u8 *ptr, u8 val)
#define pv_kick(c) __pv_kick(c)
#define pv_wait(p, v) __pv_wait(p, v)

-/*
- * PV unfair trylock count tracking function
- */
-static inline int qstat_spin_steal_lock(struct qspinlock *lock)
-{
- int ret = pv_queued_spin_steal_lock(lock);
-
- qstat_inc(qstat_pv_lock_stealing, ret);
- return ret;
-}
-#undef queued_spin_trylock
-#define queued_spin_trylock(l) qstat_spin_steal_lock(l)
-
#else /* CONFIG_QUEUED_LOCK_STAT */

static inline void qstat_inc(enum qlock_stats stat, bool cond) { }
\
 
 \ /
  Last update: 2016-02-29 13:01    [W:0.055 / U:0.892 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site