1 files changed, 8 insertions, 31 deletions

diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c
index 368b840e7508..f186d57df2c6 100644
--- a/mm/mmap_lock.c
+++ b/mm/mmap_lock.c
@@ -19,43 +19,23 @@ EXPORT_TRACEPOINT_SYMBOL(mmap_lock_released);
 
 #ifdef CONFIG_MEMCG
 
-static atomic_t reg_refcount;
-
 /*
  * Size of the buffer for memcg path names. Ignoring stack trace support,
  * trace_events_hist.c uses MAX_FILTER_STR_VAL for this, so we also use it.
  */
 #define MEMCG_PATH_BUF_SIZE MAX_FILTER_STR_VAL
 
-int trace_mmap_lock_reg(void)
-{
-	atomic_inc(&reg_refcount);
-	return 0;
-}
-
-void trace_mmap_lock_unreg(void)
-{
-	atomic_dec(&reg_refcount);
-}
-
-#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                    \
-	do {                                                    \
-		char buf[MEMCG_PATH_BUF_SIZE];                  \
-		get_mm_memcg_path(mm, buf, sizeof(buf));        \
-		trace_mmap_lock_##type(mm, buf, ##__VA_ARGS__); \
+#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)				\
+	do {								\
+		if (trace_mmap_lock_##type##_enabled()) {		\
+			char buf[MEMCG_PATH_BUF_SIZE];                  \
+			get_mm_memcg_path(mm, buf, sizeof(buf));        \
+			trace_mmap_lock_##type(mm, buf, ##__VA_ARGS__); \
+		}							\
 	} while (0)
 
 #else /* !CONFIG_MEMCG */
 
-int trace_mmap_lock_reg(void)
-{
-	return 0;
-}
-
-void trace_mmap_lock_unreg(void)
-{
-}
-
 #define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
 	trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
 
@@ -65,16 +45,13 @@ void trace_mmap_lock_unreg(void)
 #ifdef CONFIG_MEMCG
 /*
  * Write the given mm_struct's memcg path to a buffer. If the path cannot be
- * determined or the trace event is being unregistered, empty string is written.
+ * determined, empty string is written.
  */
 static void get_mm_memcg_path(struct mm_struct *mm, char *buf, size_t buflen)
 {
 	struct mem_cgroup *memcg;
 
 	buf[0] = '\0';
-	/* No need to get path if no trace event is registered. */
-	if (!atomic_read(&reg_refcount))
-		return;
 	memcg = get_mem_cgroup_from_mm(mm);
 	if (memcg == NULL)
 		return;