lockstat: contend with points
We currently only provide points that have to wait on contention, also lists the points we have to wait for. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
7317d7b87e
commit
c7e78cff6b
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@ -71,34 +71,48 @@ Look at the current lock statistics:
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# less /proc/lock_stat
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01 lock_stat version 0.2
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01 lock_stat version 0.3
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02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
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04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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05
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06 &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60
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07 &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38
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08 --------------------------
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09 &inode->i_data.tree_lock 0 [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190
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10
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11 ...............................................................................................................................................................................................
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12
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13 dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
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14 -----------
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15 dcache_lock 180 [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230
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16 dcache_lock 165 [<ffffffff802c002a>] d_alloc+0x15a/0x210
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17 dcache_lock 33 [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70
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18 dcache_lock 1 [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130
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06 &mm->mmap_sem-W: 233 538 18446744073708 22924.27 607243.51 1342 45806 1.71 8595.89 1180582.34
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07 &mm->mmap_sem-R: 205 587 18446744073708 28403.36 731975.00 1940 412426 0.58 187825.45 6307502.88
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08 ---------------
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09 &mm->mmap_sem 487 [<ffffffff8053491f>] do_page_fault+0x466/0x928
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10 &mm->mmap_sem 179 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
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11 &mm->mmap_sem 279 [<ffffffff80210a57>] sys_mmap+0x75/0xce
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12 &mm->mmap_sem 76 [<ffffffff802a490b>] sys_munmap+0x32/0x59
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13 ---------------
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14 &mm->mmap_sem 270 [<ffffffff80210a57>] sys_mmap+0x75/0xce
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15 &mm->mmap_sem 431 [<ffffffff8053491f>] do_page_fault+0x466/0x928
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16 &mm->mmap_sem 138 [<ffffffff802a490b>] sys_munmap+0x32/0x59
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17 &mm->mmap_sem 145 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
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18
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19 ...............................................................................................................................................................................................
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20
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21 dcache_lock: 621 623 0.52 118.26 1053.02 6745 91930 0.29 316.29 118423.41
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22 -----------
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23 dcache_lock 179 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
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24 dcache_lock 113 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
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25 dcache_lock 99 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
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26 dcache_lock 104 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
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27 -----------
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28 dcache_lock 192 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
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29 dcache_lock 98 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
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30 dcache_lock 72 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
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31 dcache_lock 112 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
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This excerpt shows the first two lock class statistics. Line 01 shows the
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output version - each time the format changes this will be updated. Line 02-04
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show the header with column descriptions. Lines 05-10 and 13-18 show the actual
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show the header with column descriptions. Lines 05-18 and 20-31 show the actual
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statistics. These statistics come in two parts; the actual stats separated by a
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short separator (line 08, 14) from the contention points.
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short separator (line 08, 13) from the contention points.
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The first lock (05-10) is a read/write lock, and shows two lines above the
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The first lock (05-18) is a read/write lock, and shows two lines above the
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short separator. The contention points don't match the column descriptors,
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they have two: contentions and [<IP>] symbol.
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they have two: contentions and [<IP>] symbol. The second set of contention
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points are the points we're contending with.
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The integer part of the time values is in us.
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@ -73,6 +73,8 @@ struct lock_class_key {
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struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
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};
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#define LOCKSTAT_POINTS 4
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/*
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* The lock-class itself:
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*/
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@ -119,7 +121,8 @@ struct lock_class {
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int name_version;
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#ifdef CONFIG_LOCK_STAT
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unsigned long contention_point[4];
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unsigned long contention_point[LOCKSTAT_POINTS];
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unsigned long contending_point[LOCKSTAT_POINTS];
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#endif
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};
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@ -144,6 +147,7 @@ enum bounce_type {
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struct lock_class_stats {
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unsigned long contention_point[4];
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unsigned long contending_point[4];
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struct lock_time read_waittime;
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struct lock_time write_waittime;
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struct lock_time read_holdtime;
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@ -165,6 +169,7 @@ struct lockdep_map {
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const char *name;
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#ifdef CONFIG_LOCK_STAT
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int cpu;
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unsigned long ip;
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#endif
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};
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@ -355,7 +360,7 @@ struct lock_class_key { };
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#ifdef CONFIG_LOCK_STAT
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extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
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extern void lock_acquired(struct lockdep_map *lock);
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extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
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#define LOCK_CONTENDED(_lock, try, lock) \
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do { \
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@ -363,13 +368,13 @@ do { \
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lock_contended(&(_lock)->dep_map, _RET_IP_); \
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lock(_lock); \
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} \
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lock_acquired(&(_lock)->dep_map); \
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lock_acquired(&(_lock)->dep_map, _RET_IP_); \
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} while (0)
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#else /* CONFIG_LOCK_STAT */
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#define lock_contended(lockdep_map, ip) do {} while (0)
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#define lock_acquired(lockdep_map) do {} while (0)
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#define lock_acquired(lockdep_map, ip) do {} while (0)
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#define LOCK_CONTENDED(_lock, try, lock) \
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lock(_lock)
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@ -136,16 +136,16 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock)
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#ifdef CONFIG_LOCK_STAT
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static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
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static int lock_contention_point(struct lock_class *class, unsigned long ip)
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static int lock_point(unsigned long points[], unsigned long ip)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
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if (class->contention_point[i] == 0) {
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class->contention_point[i] = ip;
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for (i = 0; i < LOCKSTAT_POINTS; i++) {
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if (points[i] == 0) {
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points[i] = ip;
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break;
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}
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if (class->contention_point[i] == ip)
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if (points[i] == ip)
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break;
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}
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@ -185,6 +185,9 @@ struct lock_class_stats lock_stats(struct lock_class *class)
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for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
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stats.contention_point[i] += pcs->contention_point[i];
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for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
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stats.contending_point[i] += pcs->contending_point[i];
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lock_time_add(&pcs->read_waittime, &stats.read_waittime);
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lock_time_add(&pcs->write_waittime, &stats.write_waittime);
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@ -209,6 +212,7 @@ void clear_lock_stats(struct lock_class *class)
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memset(cpu_stats, 0, sizeof(struct lock_class_stats));
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}
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memset(class->contention_point, 0, sizeof(class->contention_point));
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memset(class->contending_point, 0, sizeof(class->contending_point));
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}
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static struct lock_class_stats *get_lock_stats(struct lock_class *class)
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@ -3001,7 +3005,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
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struct held_lock *hlock, *prev_hlock;
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struct lock_class_stats *stats;
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unsigned int depth;
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int i, point;
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int i, contention_point, contending_point;
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depth = curr->lockdep_depth;
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if (DEBUG_LOCKS_WARN_ON(!depth))
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@ -3025,18 +3029,22 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
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found_it:
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hlock->waittime_stamp = sched_clock();
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point = lock_contention_point(hlock_class(hlock), ip);
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contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
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contending_point = lock_point(hlock_class(hlock)->contending_point,
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lock->ip);
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stats = get_lock_stats(hlock_class(hlock));
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if (point < ARRAY_SIZE(stats->contention_point))
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stats->contention_point[point]++;
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if (contention_point < LOCKSTAT_POINTS)
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stats->contention_point[contention_point]++;
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if (contending_point < LOCKSTAT_POINTS)
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stats->contending_point[contending_point]++;
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if (lock->cpu != smp_processor_id())
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stats->bounces[bounce_contended + !!hlock->read]++;
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put_lock_stats(stats);
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}
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static void
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__lock_acquired(struct lockdep_map *lock)
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__lock_acquired(struct lockdep_map *lock, unsigned long ip)
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{
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struct task_struct *curr = current;
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struct held_lock *hlock, *prev_hlock;
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@ -3085,6 +3093,7 @@ found_it:
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put_lock_stats(stats);
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lock->cpu = cpu;
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lock->ip = ip;
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}
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void lock_contended(struct lockdep_map *lock, unsigned long ip)
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@ -3106,7 +3115,7 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
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}
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EXPORT_SYMBOL_GPL(lock_contended);
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void lock_acquired(struct lockdep_map *lock)
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void lock_acquired(struct lockdep_map *lock, unsigned long ip)
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{
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unsigned long flags;
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@ -3119,7 +3128,7 @@ void lock_acquired(struct lockdep_map *lock)
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raw_local_irq_save(flags);
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check_flags(flags);
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current->lockdep_recursion = 1;
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__lock_acquired(lock);
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__lock_acquired(lock, ip);
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current->lockdep_recursion = 0;
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raw_local_irq_restore(flags);
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}
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@ -557,7 +557,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
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if (stats->read_holdtime.nr)
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namelen += 2;
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for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
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for (i = 0; i < LOCKSTAT_POINTS; i++) {
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char sym[KSYM_SYMBOL_LEN];
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char ip[32];
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@ -574,6 +574,23 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
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stats->contention_point[i],
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ip, sym);
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}
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for (i = 0; i < LOCKSTAT_POINTS; i++) {
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char sym[KSYM_SYMBOL_LEN];
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char ip[32];
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if (class->contending_point[i] == 0)
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break;
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if (!i)
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seq_line(m, '-', 40-namelen, namelen);
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sprint_symbol(sym, class->contending_point[i]);
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snprintf(ip, sizeof(ip), "[<%p>]",
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(void *)class->contending_point[i]);
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seq_printf(m, "%40s %14lu %29s %s\n", name,
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stats->contending_point[i],
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ip, sym);
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}
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if (i) {
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seq_puts(m, "\n");
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seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
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@ -583,7 +600,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
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static void seq_header(struct seq_file *m)
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{
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seq_printf(m, "lock_stat version 0.2\n");
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seq_printf(m, "lock_stat version 0.3\n");
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seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
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seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
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"%14s %14s\n",
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@ -184,7 +184,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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}
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done:
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lock_acquired(&lock->dep_map);
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lock_acquired(&lock->dep_map, ip);
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/* got the lock - rejoice! */
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mutex_remove_waiter(lock, &waiter, task_thread_info(task));
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debug_mutex_set_owner(lock, task_thread_info(task));
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