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Commit 01f38497 authored by Joel Fernandes (Google)'s avatar Joel Fernandes (Google) Committed by Steven Rostedt (VMware)
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lockdep: Use this_cpu_ptr instead of get_cpu_var stats 

get_cpu_var disables preemption which has the potential to call into the
preemption disable trace points causing some complications. There's also
no need to disable preemption in uses of get_lock_stats anyway since
preempt is already disabled. So lets simplify the code.

Link: http://lkml.kernel.org/r/20180730222423.196630-2-joel@joelfernandes.org



Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 6fc7c411

kernel/locking/lockdep.c

+1 −9
Original line number Diff line number Diff line
@@ -248,12 +248,7 @@ void clear_lock_stats(struct lock_class *class) 


static struct lock_class_stats *get_lock_stats(struct lock_class *class)

{

	return &get_cpu_var(cpu_lock_stats)[class - lock_classes];

}



static void put_lock_stats(struct lock_class_stats *stats)

{

	put_cpu_var(cpu_lock_stats);

	return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes];

}



static void lock_release_holdtime(struct held_lock *hlock)
@@ -271,7 +266,6 @@ static void lock_release_holdtime(struct held_lock *hlock) 
		lock_time_inc(&stats->read_holdtime, holdtime);

	else

		lock_time_inc(&stats->write_holdtime, holdtime);

	put_lock_stats(stats);

}

#else

static inline void lock_release_holdtime(struct held_lock *hlock)
@@ -4090,7 +4084,6 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) 
		stats->contending_point[contending_point]++;

	if (lock->cpu != smp_processor_id())

		stats->bounces[bounce_contended + !!hlock->read]++;

	put_lock_stats(stats);

}



static void
@@ -4138,7 +4131,6 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) 
	}

	if (lock->cpu != cpu)

		stats->bounces[bounce_acquired + !!hlock->read]++;

	put_lock_stats(stats);



	lock->cpu = cpu;

	lock->ip = ip;