f2fs: adjust showing of extent cache stat

This patch alters to replace total hit stat with rbtree hit stat,
and then adjust showing of extent cache stat:

Hit Count:
L1-1: for largest node hit count;
L1-2: for last cached node hit count;
L2: for extent node hit after lookuping in rbtree.

Hit Ratio:
ratio (hit count / total lookup count)

Inner Struct Count:
tree count, node count.

Before:
Extent Hit Ratio: 0 / 2

Extent Tree Count: 3

Extent Node Count: 2

Patched:
Exten Cacache:
  - Hit Count: L1-1:4871 L1-2:2074 L2:208
  - Hit Ratio: 1% (7153 / 550751)
  - Inner Struct Count: tree: 26560, node: 11824
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/debug.c

@@ -35,7 +35,8 @@ static void update_general_status(struct f2fs_sb_info *sbi)
 	/* validation check of the segment numbers */
 	si->hit_largest = atomic_read(&sbi->read_hit_largest);
 	si->hit_cached = atomic_read(&sbi->read_hit_cached);
-	si->hit_ext = atomic_read(&sbi->read_hit_ext);
+	si->hit_rbtree = atomic_read(&sbi->read_hit_rbtree);
+	si->hit_total = si->hit_largest + si->hit_cached + si->hit_rbtree;
 	si->total_ext = atomic_read(&sbi->total_hit_ext);
 	si->ext_tree = sbi->total_ext_tree;
 	si->ext_node = atomic_read(&sbi->total_ext_node);
@@ -281,11 +282,16 @@ static int stat_show(struct seq_file *s, void *v)
 				si->bg_data_blks);
 		seq_printf(s, "  - node blocks : %d (%d)\n", si->node_blks,
 				si->bg_node_blks);
-		seq_printf(s, "\nExtent Hit Ratio: L1-1:%d L1-2:%d L2:%d / %d\n",
+		seq_puts(s, "\nExtent Cache:\n");
+		seq_printf(s, "  - Hit Count: L1-1:%d L1-2:%d L2:%d\n",
 				si->hit_largest, si->hit_cached,
-				si->hit_ext, si->total_ext);
-		seq_printf(s, "\nExtent Tree Count: %d\n", si->ext_tree);
-		seq_printf(s, "\nExtent Node Count: %d\n", si->ext_node);
+				si->hit_rbtree);
+		seq_printf(s, "  - Hit Ratio: %d%% (%d / %d)\n",
+				!si->total_ext ? 0 :
+				(si->hit_total * 100) / si->total_ext,
+				si->hit_total, si->total_ext);
+		seq_printf(s, "  - Inner Struct Count: tree: %d, node: %d\n",
+				si->ext_tree, si->ext_node);
 		seq_puts(s, "\nBalancing F2FS Async:\n");
 		seq_printf(s, "  - inmem: %4d, wb: %4d\n",
 			   si->inmem_pages, si->wb_pages);
@@ -373,7 +379,7 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
 	sbi->stat_info = si;
 
 	atomic_set(&sbi->total_hit_ext, 0);
-	atomic_set(&sbi->read_hit_ext, 0);
+	atomic_set(&sbi->read_hit_rbtree, 0);
 	atomic_set(&sbi->read_hit_largest, 0);
 	atomic_set(&sbi->read_hit_cached, 0);
 

fs/f2fs/extent_cache.c

@@ -99,12 +99,14 @@ static struct extent_node *__lookup_extent_tree(struct f2fs_sb_info *sbi,
 	while (node) {
 		en = rb_entry(node, struct extent_node, rb_node);
 
-		if (fofs < en->ei.fofs)
+		if (fofs < en->ei.fofs) {
 			node = node->rb_left;
-		else if (fofs >= en->ei.fofs + en->ei.len)
+		} else if (fofs >= en->ei.fofs + en->ei.len) {
 			node = node->rb_right;
-		else
+		} else {
+			stat_inc_rbtree_node_hit(sbi);
 			return en;
+		}
 	}
 	return NULL;
 }
@@ -281,7 +283,6 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 			et->largest.fofs + et->largest.len > pgofs) {
 		*ei = et->largest;
 		ret = true;
-		stat_inc_read_hit(sbi);
 		stat_inc_largest_node_hit(sbi);
 		goto out;
 	}
@@ -295,7 +296,6 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 		et->cached_en = en;
 		spin_unlock(&sbi->extent_lock);
 		ret = true;
-		stat_inc_read_hit(sbi);
 	}
 out:
 	stat_inc_total_hit(sbi);

fs/f2fs/f2fs.h

@@ -788,7 +788,7 @@ struct f2fs_sb_info {
 	unsigned int block_count[2];		/* # of allocated blocks */
 	atomic_t inplace_count;		/* # of inplace update */
 	atomic_t total_hit_ext;			/* # of lookup extent cache */
-	atomic_t read_hit_ext;			/* # of hit extent cache */
+	atomic_t read_hit_rbtree;		/* # of hit rbtree extent node */
 	atomic_t read_hit_largest;		/* # of hit largest extent node */
 	atomic_t read_hit_cached;		/* # of hit cached extent node */
 	atomic_t inline_xattr;			/* # of inline_xattr inodes */
@@ -1826,7 +1826,8 @@ struct f2fs_stat_info {
 	struct f2fs_sb_info *sbi;
 	int all_area_segs, sit_area_segs, nat_area_segs, ssa_area_segs;
 	int main_area_segs, main_area_sections, main_area_zones;
-	int hit_largest, hit_cached, hit_ext, total_ext, ext_tree, ext_node;
+	int hit_largest, hit_cached, hit_rbtree, hit_total, total_ext;
+	int ext_tree, ext_node;
 	int ndirty_node, ndirty_dent, ndirty_dirs, ndirty_meta;
 	int nats, dirty_nats, sits, dirty_sits, fnids;
 	int total_count, utilization;
@@ -1863,7 +1864,7 @@ static inline struct f2fs_stat_info *F2FS_STAT(struct f2fs_sb_info *sbi)
 #define stat_inc_dirty_dir(sbi)		((sbi)->n_dirty_dirs++)
 #define stat_dec_dirty_dir(sbi)		((sbi)->n_dirty_dirs--)
 #define stat_inc_total_hit(sbi)		(atomic_inc(&(sbi)->total_hit_ext))
-#define stat_inc_read_hit(sbi)		(atomic_inc(&(sbi)->read_hit_ext))
+#define stat_inc_rbtree_node_hit(sbi)	(atomic_inc(&(sbi)->read_hit_rbtree))
 #define stat_inc_largest_node_hit(sbi)	(atomic_inc(&(sbi)->read_hit_largest))
 #define stat_inc_cached_node_hit(sbi)	(atomic_inc(&(sbi)->read_hit_cached))
 #define stat_inc_inline_xattr(inode)					\
@@ -1945,7 +1946,7 @@ void f2fs_destroy_root_stats(void);
 #define stat_inc_dirty_dir(sbi)
 #define stat_dec_dirty_dir(sbi)
 #define stat_inc_total_hit(sb)
-#define stat_inc_read_hit(sb)
+#define stat_inc_rbtree_node_hit(sb)
 #define stat_inc_largest_node_hit(sbi)
 #define stat_inc_cached_node_hit(sbi)
 #define stat_inc_inline_xattr(inode)