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Subject[PATCH 2/2] locking/lockdep: Make global debug_locks* variables read-mostly
Date
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>
---
include/linux/debug_locks.h | 4 ++--
lib/debug_locks.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index 120225e..257ab3c 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -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)
diff --git a/lib/debug_locks.c b/lib/debug_locks.c
index 124fdf2..ce51749 100644
--- a/lib/debug_locks.c
+++ b/lib/debug_locks.c
@@ -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;
EXPORT_SYMBOL_GPL(debug_locks);

/*
@@ -29,7 +29,7 @@
* 'silent failure': nothing is printed to the console when
* a locking bug is detected.
*/
-int debug_locks_silent;
+int debug_locks_silent __read_mostly;
EXPORT_SYMBOL_GPL(debug_locks_silent);

/*
--
1.8.3.1
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