locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs

The percpu event counts used by qspinlock code can be useful for
other locking code as well. So a new set of lockevent_* counting APIs
is introduced with the lock event names extracted out into the new
lock_events_list.h header file for easier addition in the future.

The existing qstat_inc() calls are replaced by either lockevent_inc() or
lockevent_cond_inc() calls.

The qstat_hop() call is renamed to lockevent_pv_hop(). The "reset_counters"
debugfs file is also renamed to ".reset_counts".

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20190404174320.22416-8-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 10 insertions, 9 deletions

diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 8f36c27c1794..89bab079e7a4 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -89,7 +89,7 @@ static inline bool pv_hybrid_queued_unfair_trylock(struct qspinlock *lock)
 
 		if (!(val & _Q_LOCKED_PENDING_MASK) &&
 		   (cmpxchg_acquire(&lock->locked, 0, _Q_LOCKED_VAL) == 0)) {
-			qstat_inc(qstat_pv_lock_stealing, true);
+			lockevent_inc(pv_lock_stealing);
 			return true;
 		}
 		if (!(val & _Q_TAIL_MASK) || (val & _Q_PENDING_MASK))
@@ -219,7 +219,7 @@ static struct qspinlock **pv_hash(struct qspinlock *lock, struct pv_node *node)
 		hopcnt++;
 		if (!cmpxchg(&he->lock, NULL, lock)) {
 			WRITE_ONCE(he->node, node);
-			qstat_hop(hopcnt);
+			lockevent_pv_hop(hopcnt);
 			return &he->lock;
 		}
 	}
@@ -320,8 +320,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
 		smp_store_mb(pn->state, vcpu_halted);
 
 		if (!READ_ONCE(node->locked)) {
-			qstat_inc(qstat_pv_wait_node, true);
-			qstat_inc(qstat_pv_wait_early, wait_early);
+			lockevent_inc(pv_wait_node);
+			lockevent_cond_inc(pv_wait_early, wait_early);
 			pv_wait(&pn->state, vcpu_halted);
 		}
 
@@ -339,7 +339,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
 		 * So it is better to spin for a while in the hope that the
 		 * MCS lock will be released soon.
 		 */
-		qstat_inc(qstat_pv_spurious_wakeup, !READ_ONCE(node->locked));
+		lockevent_cond_inc(pv_spurious_wakeup,
+				  !READ_ONCE(node->locked));
 	}
 
 	/*
@@ -416,7 +417,7 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node)
 	/*
 	 * Tracking # of slowpath locking operations
 	 */
-	qstat_inc(qstat_lock_slowpath, true);
+	lockevent_inc(lock_slowpath);
 
 	for (;; waitcnt++) {
 		/*
@@ -464,8 +465,8 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node)
 			}
 		}
 		WRITE_ONCE(pn->state, vcpu_hashed);
-		qstat_inc(qstat_pv_wait_head, true);
-		qstat_inc(qstat_pv_wait_again, waitcnt);
+		lockevent_inc(pv_wait_head);
+		lockevent_cond_inc(pv_wait_again, waitcnt);
 		pv_wait(&lock->locked, _Q_SLOW_VAL);
 
 		/*
@@ -528,7 +529,7 @@ __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked)
 	 * vCPU is harmless other than the additional latency in completing
 	 * the unlock.
 	 */
-	qstat_inc(qstat_pv_kick_unlock, true);
+	lockevent_inc(pv_kick_unlock);
 	pv_kick(node->cpu);
 }