Commit 3365e779 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

lockdep: Use cpu_clock() for lockstat 



Some tracepoint magic (TRACE_EVENT(lock_acquired)) relies on
the fact that lock hold times are positive and uses div64 on
that. That triggered a build warning on MIPS, and probably
causes bad output in certain circumstances as well.

Make it truly positive.

Reported-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1254818502.21044.112.camel@laptop>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 36a07902

kernel/lockdep.c

+12 −8
Original line number Diff line number Diff line
@@ -142,6 +142,11 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock) 
#ifdef CONFIG_LOCK_STAT

static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);



static inline u64 lockstat_clock(void)

{

	return cpu_clock(smp_processor_id());

}



static int lock_point(unsigned long points[], unsigned long ip)

{

	int i;
@@ -158,7 +163,7 @@ static int lock_point(unsigned long points[], unsigned long ip) 
	return i;

}



static void lock_time_inc(struct lock_time *lt, s64 time)

static void lock_time_inc(struct lock_time *lt, u64 time)

{

	if (time > lt->max)

		lt->max = time;
@@ -234,12 +239,12 @@ static void put_lock_stats(struct lock_class_stats *stats) 
static void lock_release_holdtime(struct held_lock *hlock)

{

	struct lock_class_stats *stats;

	s64 holdtime;

	u64 holdtime;



	if (!lock_stat)

		return;



	holdtime = sched_clock() - hlock->holdtime_stamp;

	holdtime = lockstat_clock() - hlock->holdtime_stamp;



	stats = get_lock_stats(hlock_class(hlock));

	if (hlock->read)
@@ -2792,7 +2797,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	hlock->references = references;

#ifdef CONFIG_LOCK_STAT

	hlock->waittime_stamp = 0;

	hlock->holdtime_stamp = sched_clock();

	hlock->holdtime_stamp = lockstat_clock();

#endif



	if (check == 2 && !mark_irqflags(curr, hlock))
@@ -3322,7 +3327,7 @@ found_it: 
	if (hlock->instance != lock)

		return;



	hlock->waittime_stamp = sched_clock();

	hlock->waittime_stamp = lockstat_clock();



	contention_point = lock_point(hlock_class(hlock)->contention_point, ip);

	contending_point = lock_point(hlock_class(hlock)->contending_point,
@@ -3345,8 +3350,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) 
	struct held_lock *hlock, *prev_hlock;

	struct lock_class_stats *stats;

	unsigned int depth;

	u64 now;

	s64 waittime = 0;

	u64 now, waittime = 0;

	int i, cpu;



	depth = curr->lockdep_depth;
@@ -3374,7 +3378,7 @@ found_it: 


	cpu = smp_processor_id();

	if (hlock->waittime_stamp) {

		now = sched_clock();

		now = lockstat_clock();

		waittime = now - hlock->waittime_stamp;

		hlock->holdtime_stamp = now;

	}

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