locking/lockdep: Make global debug_locks* variables read-mostly
authorWaiman Long <longman@redhat.com>
Fri, 19 Oct 2018 01:45:18 +0000 (21:45 -0400)
committerIngo Molnar <mingo@kernel.org>
Fri, 19 Oct 2018 05:53:18 +0000 (07:53 +0200)
Make the frequently used lockdep global variable debug_locks read-mostly.
As debug_locks_silent is sometime used together with debug_locks,
it is also made read-mostly so that they can be close together.

With false cacheline sharing, cacheline contention problem can happen
depending on what get put into the same cacheline as debug_locks.

Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
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: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1539913518-15598-2-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

index 120225e9a366ba2c34658e0dc6e4fd6da52878a7..257ab3c92cb8ad5b78f88f8eb81974f550c657c3 100644 (file)
@@ -8,8 +8,8 @@
 struct task_struct;
-extern int debug_locks;
-extern int debug_locks_silent;
+extern int debug_locks __read_mostly;
+extern int debug_locks_silent __read_mostly;
 static inline int __debug_locks_off(void)
index 124fdf238b3d95739292424ef40c12b6b3c22308..ce51749cc145f22e1ffbd2f5d22867f33b1b25cb 100644 (file)
@@ -21,7 +21,7 @@
  * that would just muddy the log. So we report the first one and
  * shut up after that.
-int debug_locks = 1;
+int debug_locks __read_mostly = 1;
@@ -29,7 +29,7 @@ EXPORT_SYMBOL_GPL(debug_locks);
  * 'silent failure': nothing is printed to the console when
  * a locking bug is detected.
-int debug_locks_silent;
+int debug_locks_silent __read_mostly;