Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 35 insertions, 3 deletions

diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt
index 65f4c795015d..cef00d42ed5b 100644
--- a/Documentation/lockstat.txt
+++ b/Documentation/lockstat.txt
@@ -12,8 +12,9 @@ Because things like lock contention can severely impact performance.
 - HOW
 
 Lockdep already has hooks in the lock functions and maps lock instances to
-lock classes. We build on that. The graph below shows the relation between
-the lock functions and the various hooks therein.
+lock classes. We build on that (see Documentation/lockdep-design.txt).
+The graph below shows the relation between the lock functions and the various
+hooks therein.
 
         __acquire
             |
@@ -128,6 +129,37 @@ points are the points we're contending with.
 
 The integer part of the time values is in us.
 
+Dealing with nested locks, subclasses may appear:
+
+32...............................................................................................................................................................................................
+33
+34                               &rq->lock:         13128          13128           0.43         190.53      103881.26          97454        3453404           0.00         401.11    13224683.11
+35                               ---------
+36                               &rq->lock            645          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
+37                               &rq->lock            297          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+38                               &rq->lock            360          [<ffffffff8103c4c5>] select_task_rq_fair+0x1f0/0x74a
+39                               &rq->lock            428          [<ffffffff81045f98>] scheduler_tick+0x46/0x1fb
+40                               ---------
+41                               &rq->lock             77          [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
+42                               &rq->lock            174          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+43                               &rq->lock           4715          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
+44                               &rq->lock            893          [<ffffffff81340524>] schedule+0x157/0x7b8
+45
+46...............................................................................................................................................................................................
+47
+48                             &rq->lock/1:         11526          11488           0.33         388.73      136294.31          21461          38404           0.00          37.93      109388.53
+49                             -----------
+50                             &rq->lock/1          11526          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
+51                             -----------
+52                             &rq->lock/1           5645          [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
+53                             &rq->lock/1           1224          [<ffffffff81340524>] schedule+0x157/0x7b8
+54                             &rq->lock/1           4336          [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
+55                             &rq->lock/1            181          [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+
+Line 48 shows statistics for the second subclass (/1) of &rq->lock class
+(subclass starts from 0), since in this case, as line 50 suggests,
+double_rq_lock actually acquires a nested lock of two spinlocks.
+
 View the top contending locks:
 
 # grep : /proc/lock_stat | head
@@ -136,7 +168,7 @@ View the top contending locks:
                              dcache_lock:          1037           1161           0.38          45.32         774.51           6611         243371           0.15         306.48       77387.24
                          &inode->i_mutex:           161            286 18446744073709       62882.54     1244614.55           3653          20598 18446744073709       62318.60     1693822.74
                          &zone->lru_lock:            94             94           0.53           7.33          92.10           4366          32690           0.29          59.81       16350.06
-              &inode->i_data.i_mmap_lock:            79             79           0.40           3.77          53.03          11779          87755           0.28         116.93       29898.44
+              &inode->i_data.i_mmap_mutex:            79             79           0.40           3.77          53.03          11779          87755           0.28         116.93       29898.44
                         &q->__queue_lock:            48             50           0.52          31.62          86.31            774          13131           0.17         113.08       12277.52
                         &rq->rq_lock_key:            43             47           0.74          68.50         170.63           3706          33929           0.22         107.99       17460.62
                       &rq->rq_lock_key#2:            39             46           0.75           6.68          49.03           2979          32292           0.17         125.17       17137.63