[PATCH mm-new v2] mm/zblock: add debugfs

[Igor Belousov <igor.b@beldev.am>]

Add debugfs entry to monitor number of blocks allocated for different
block sizes.

Signed-off-by: Igor Belousov <igor.b@beldev.am>

---
 mm/zblock.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/mm/zblock.c b/mm/zblock.c
index 6afe6986260d..e2036a6e1617 100644
--- a/mm/zblock.c
+++ b/mm/zblock.c
@@ -17,6 +17,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/atomic.h>
+#include <linux/debugfs.h>
 #include <linux/list.h>
 #include <linux/mm.h>
 #include <linux/module.h>
@@ -27,6 +28,7 @@
 #include "zblock.h"
 
 static struct rb_root block_desc_tree = RB_ROOT;
+static struct dentry *zblock_debugfs_root;
 
 /* Encode handle of a particular slot in the pool using metadata */
 static inline unsigned long metadata_to_handle(struct zblock_block *block,
@@ -111,6 +113,22 @@ static struct zblock_block *alloc_block(struct zblock_pool *pool,
 	return block;
 }
 
+static int zblock_blocks_show(struct seq_file *s, void *v)
+{
+	struct zblock_pool *pool = s->private;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(block_desc); i++) {
+		struct block_list *block_list = &pool->block_lists[i];
+
+		seq_printf(s, "%d: %ld blocks of %d pages (total %ld pages)\n",
+			i, block_list->block_count, 1 << block_desc[i].order,
+			block_list->block_count << block_desc[i].order);
+	}
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(zblock_blocks);
+
 /*****************
  * API Functions
  *****************/
@@ -140,6 +158,9 @@ static struct zblock_pool *zblock_create_pool(gfp_t gfp)
 		INIT_LIST_HEAD(&block_list->active_list);
 		block_list->block_count = 0;
 	}
+
+	debugfs_create_file("blocks", S_IFREG | 0444, zblock_debugfs_root,
+			    pool, &zblock_blocks_fops);
 	return pool;
 }
 
@@ -426,12 +447,15 @@ static int __init init_zblock(void)
 		return ret;
 
 	zpool_register_driver(&zblock_zpool_driver);
+
+	zblock_debugfs_root = debugfs_create_dir("zblock", NULL);
 	return 0;
 }
 
 static void __exit exit_zblock(void)
 {
 	zpool_unregister_driver(&zblock_zpool_driver);
+	debugfs_remove_recursive(zblock_debugfs_root);
 	delete_rbtree();
 }
 
-- 
2.49.0