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lockdep.c likely

RFC PATCH In review Michal Piotrowski 2 participants 2 messages Jul 9, 2006

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Michal Piotrowski

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#0 lore raw

RFC PATCH 1/1 lockdep.c likely

Hi,

I have noticed this

+unlikely | 53202934| 80576 trace_softirqs_on()@:/usr/src/linux-mm/kernel/lockdep.c@1861
[..]
+unlikely | 53202350| 80542 trace_softirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1895
[..]
+unlikely |272060329| 3784394 trace_hardirqs_on()@:/usr/src/linux-mm/kernel/lockdep.c@1787 [..]
+unlikely |361155686| 2959425 check_unlock()@:/usr/src/linux-mm/kernel/lockdep.c@2197 [..]

+unlikely |  1821294|  1140788  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1977
 unlikely |        0|  2962331  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1965
 unlikely |        0|  2962035  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1962
+unlikely |361188304|  2961749  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1959
[..]
+unlikely | 14528808|   413114  debug_check_no_locks_freed()@:/usr/src/linux-mm/kernel/lockdep.c@2607
 likely   |    92394|      156  lock_kernel()@:/usr/src/linux-mm/lib/kernel_lock.c@70
 unlikely |        0|   305177  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1927
 unlikely |        0|   305177  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1925
+unlikely |  2156369|   305176  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1922
 unlikely |        0|  4412613  trace_hardirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1837
+unlikely |319757688|  4409721  trace_hardirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1834

in /proc/likely_prof

I'm not sure of it, but patch below should optimalize it.

Regards,
Michal

--
Michal K. K. Piotrowski
LTG - Linux Testers Group
(http://www.stardust.webpages.pl/ltg/wiki/)

Signed-off-by Michal Piotrowski <[email protected]>
kernel/lockdep.c +9 -9
diff -uprN -X linux-mm/Documentation/dontdiff linux-mm-clean/kernel/lockdep.c linux-mm/kernel/lockdep.c
@@ -1784,7 +1784,7 @@ void trace_hardirqs_on(void)
 	struct task_struct *curr = current;
 	unsigned long ip;
 
-	if (unlikely(!debug_locks || current->lockdep_recursion))
+	if (likely(!debug_locks || current->lockdep_recursion))
 		return;
 
 	if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))

@@ -1831,7 +1831,7 @@ void trace_hardirqs_off(void)
 {
 	struct task_struct *curr = current;
 
-	if (unlikely(!debug_locks || current->lockdep_recursion))
+	if (likely(!debug_locks || current->lockdep_recursion))
 		return;
 
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))

@@ -1858,7 +1858,7 @@ void trace_softirqs_on(unsigned long ip)
 {
 	struct task_struct *curr = current;
 
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return;
 
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))

@@ -1892,7 +1892,7 @@ void trace_softirqs_off(unsigned long ip
 {
 	struct task_struct *curr = current;
 
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return;
 
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))

@@ -1919,7 +1919,7 @@ void trace_softirqs_off(unsigned long ip
 void lockdep_init_map(struct lockdep_map *lock, const char *name,
 		      struct lock_class_key *key)
 {
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return;
 
 	if (DEBUG_LOCKS_WARN_ON(!key))

@@ -1956,7 +1956,7 @@ static int __lock_acquire(struct lockdep
 	int chain_head = 0;
 	u64 chain_key;
 
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return 0;
 
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))

@@ -1974,7 +1974,7 @@ static int __lock_acquire(struct lockdep
 	/*
 	 * Not cached yet or subclass?
 	 */
-	if (unlikely(!class)) {
+	if (likely(!class)) {
 		class = register_lock_class(lock, subclass);
 		if (!class)
 			return 0;

@@ -2194,7 +2194,7 @@ print_unlock_inbalance_bug(struct task_s
 static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
 			unsigned long ip)
 {
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return 0;
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
 		return 0;

@@ -2604,7 +2604,7 @@ void debug_check_no_locks_freed(const vo
 	unsigned long flags;
 	int i;
 
-	if (unlikely(!debug_locks))
+	if (likely(!debug_locks))
 		return;
 
 	local_irq_save(flags);
#1 lore raw
Quoted 25 lines · Michal Piotrowski

Hi,

I have noticed this

(quoted diff) +9 -0
+unlikely | 53202934|    80576  trace_softirqs_on()@:/usr/src/linux-mm/kernel/lockdep.c@1861
[..]
+unlikely | 53202350|    80542  trace_softirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1895
[..]
+unlikely |272060329|  3784394  trace_hardirqs_on()@:/usr/src/linux-mm/kernel/lockdep.c@1787
[..]
+unlikely |361155686|  2959425  check_unlock()@:/usr/src/linux-mm/kernel/lockdep.c@2197
[..]
+unlikely |  1821294|  1140788  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1977
 unlikely |        0|  2962331  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1965
 unlikely |        0|  2962035  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1962
+unlikely |361188304|  2961749  __lock_acquire()@:/usr/src/linux-mm/kernel/lockdep.c@1959
[..]
+unlikely | 14528808|   413114  debug_check_no_locks_freed()@:/usr/src/linux-mm/kernel/lockdep.c@2607
 likely   |    92394|      156  lock_kernel()@:/usr/src/linux-mm/lib/kernel_lock.c@70
 unlikely |        0|   305177  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1927
 unlikely |        0|   305177  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1925
+unlikely |  2156369|   305176  lockdep_init_map()@:/usr/src/linux-mm/kernel/lockdep.c@1922
 unlikely |        0|  4412613  trace_hardirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1837
+unlikely |319757688|  4409721  trace_hardirqs_off()@:/usr/src/linux-mm/kernel/lockdep.c@1834
Quoted 3 lines

in /proc/likely_prof

I'm not sure of it, but patch below should optimalize it.

this is only likely after you've hit a lockdep message though..