six locks: Lock contended tracepoints

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/six.c

@@ -11,6 +11,8 @@
 #include <linux/sched/task.h>
 #include <linux/slab.h>
 
+#include <trace/events/lock.h>
+
 #include "six.h"
 
 #ifdef DEBUG
@@ -462,11 +464,12 @@ static int six_lock_slowpath(struct six_lock *lock, enum six_lock_type type,
 		smp_mb__after_atomic();
 	}
 
+	trace_contention_begin(lock, 0);
+	lock_contended(&lock->dep_map, ip);
+
 	if (six_optimistic_spin(lock, type))
 		goto out;
 
-	lock_contended(&lock->dep_map, ip);
-
 	wait->task		= current;
 	wait->lock_want		= type;
 	wait->lock_acquired	= false;
@@ -546,6 +549,7 @@ static int six_lock_slowpath(struct six_lock *lock, enum six_lock_type type,
 		six_clear_bitmask(lock, SIX_LOCK_HELD_write);
 		six_lock_wakeup(lock, atomic_read(&lock->state), SIX_LOCK_read);
 	}
+	trace_contention_end(lock, 0);
 
 	return ret;
 }