Commit 01a14bda authored Oct 18, 2018 by Waiman Long Committed by Ingo Molnar Oct 19, 2018

locking/lockdep: Make global debug_locks* variables read-mostly



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>

parent 9506a742

include/linux/debug_locks.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -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)

lib/debug_locks.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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 @@ 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;
		EXPORT_SYMBOL_GPL(debug_locks_silent);

		/*

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