ext4: improve extents status tree trace point

This commit improves the trace point of extents status tree.  We rename
trace_ext4_es_shrink_enter in ext4_es_count() because it is also used
in ext4_es_scan() and we can not identify them from the result.

Further this commit fixes a variable name in trace point in order to
keep consistency with others.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/extents_status.c

@@ -1019,7 +1019,7 @@ static unsigned long ext4_es_count(struct shrinker *shrink,
 
 	sbi = container_of(shrink, struct ext4_sb_info, s_es_shrinker);
 	nr = percpu_counter_read_positive(&sbi->s_extent_cache_cnt);
-	trace_ext4_es_shrink_enter(sbi->s_sb, sc->nr_to_scan, nr);
+	trace_ext4_es_shrink_count(sbi->s_sb, sc->nr_to_scan, nr);
 	return nr;
 }
 
@@ -1032,14 +1032,14 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
 	int ret, nr_shrunk;
 
 	ret = percpu_counter_read_positive(&sbi->s_extent_cache_cnt);
-	trace_ext4_es_shrink_enter(sbi->s_sb, nr_to_scan, ret);
+	trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret);
 
 	if (!nr_to_scan)
 		return ret;
 
 	nr_shrunk = __ext4_es_shrink(sbi, nr_to_scan, NULL);
 
-	trace_ext4_es_shrink_exit(sbi->s_sb, nr_shrunk, ret);
+	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
 	return nr_shrunk;
 }
 

include/trace/events/ext4.h

@@ -2369,7 +2369,7 @@ TRACE_EVENT(ext4_es_lookup_extent_exit,
 		  show_extent_status(__entry->found ? __entry->status : 0))
 );
 
-TRACE_EVENT(ext4_es_shrink_enter,
+DECLARE_EVENT_CLASS(ext4__es_shrink_enter,
 	TP_PROTO(struct super_block *sb, int nr_to_scan, int cache_cnt),
 
 	TP_ARGS(sb, nr_to_scan, cache_cnt),
@@ -2391,26 +2391,38 @@ TRACE_EVENT(ext4_es_shrink_enter,
 		  __entry->nr_to_scan, __entry->cache_cnt)
 );
 
-TRACE_EVENT(ext4_es_shrink_exit,
-	TP_PROTO(struct super_block *sb, int shrunk_nr, int cache_cnt),
+DEFINE_EVENT(ext4__es_shrink_enter, ext4_es_shrink_count,
+	TP_PROTO(struct super_block *sb, int nr_to_scan, int cache_cnt),
+
+	TP_ARGS(sb, nr_to_scan, cache_cnt)
+);
+
+DEFINE_EVENT(ext4__es_shrink_enter, ext4_es_shrink_scan_enter,
+	TP_PROTO(struct super_block *sb, int nr_to_scan, int cache_cnt),
+
+	TP_ARGS(sb, nr_to_scan, cache_cnt)
+);
+
+TRACE_EVENT(ext4_es_shrink_scan_exit,
+	TP_PROTO(struct super_block *sb, int nr_shrunk, int cache_cnt),
 
-	TP_ARGS(sb, shrunk_nr, cache_cnt),
+	TP_ARGS(sb, nr_shrunk, cache_cnt),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,	dev			)
-		__field(	int,	shrunk_nr		)
+		__field(	int,	nr_shrunk		)
 		__field(	int,	cache_cnt		)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= sb->s_dev;
-		__entry->shrunk_nr	= shrunk_nr;
+		__entry->nr_shrunk	= nr_shrunk;
 		__entry->cache_cnt	= cache_cnt;
 	),
 
-	TP_printk("dev %d,%d shrunk_nr %d cache_cnt %d",
+	TP_printk("dev %d,%d nr_shrunk %d cache_cnt %d",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
-		  __entry->shrunk_nr, __entry->cache_cnt)
+		  __entry->nr_shrunk, __entry->cache_cnt)
 );
 
 TRACE_EVENT(ext4_collapse_range,