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

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

[Vitaly Wool]

From: 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>
Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se>

---

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

diff --git a/mm/zblock.c b/mm/zblock.c
index 6afe6986260d..7182b1ac85ad 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, block_desc[i].num_pages,
+			block_list->block_count * block_desc[i].num_pages);
+	}
+	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

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

[kernel test robot]

Hi Vitaly,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Vitaly-Wool/mm-zblock-add-debugfs/20250428-042209
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250427201958.491806-1-vitaly.wool%40konsulko.se
patch subject: [PATCH mm-new] mm/zblock: add debugfs
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20250428/202504280934.X1Gqvqj1-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250428/202504280934.X1Gqvqj1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504280934.X1Gqvqj1-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/zblock.c:125:46: error: no member named 'num_pages' in 'struct block_desc'
     125 |                         i, block_list->block_count, block_desc[i].num_pages,
         |                                                     ~~~~~~~~~~~~~ ^
   mm/zblock.c:126:44: error: no member named 'num_pages' in 'struct block_desc'
     126 |                         block_list->block_count * block_desc[i].num_pages);
         |                                                   ~~~~~~~~~~~~~ ^
   2 errors generated.


vim +125 mm/zblock.c

   115	
   116	static int zblock_blocks_show(struct seq_file *s, void *v)
   117	{
   118		struct zblock_pool *pool = s->private;
   119		int i;
   120	
   121		for (i = 0; i < ARRAY_SIZE(block_desc); i++) {
   122			struct block_list *block_list = &pool->block_lists[i];
   123	
   124			seq_printf(s, "%d: %ld blocks of %d pages (total %ld pages)\n",
 > 125				i, block_list->block_count, block_desc[i].num_pages,
   126				block_list->block_count * block_desc[i].num_pages);
   127		}
   128		return 0;
   129	}
   130	DEFINE_SHOW_ATTRIBUTE(zblock_blocks);
   131	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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

[kernel test robot]

Hi Vitaly,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Vitaly-Wool/mm-zblock-add-debugfs/20250428-042209
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250427201958.491806-1-vitaly.wool%40konsulko.se
patch subject: [PATCH mm-new] mm/zblock: add debugfs
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20250428/202504281254.YFJgfUac-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250428/202504281254.YFJgfUac-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504281254.YFJgfUac-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from mm/zblock.c:28:
   mm/zblock.h:24:2: error: #error Unsupported PAGE_SIZE
      24 | #error Unsupported PAGE_SIZE
         |  ^~~~~
   In file included from include/vdso/const.h:5,
                    from include/linux/const.h:4,
                    from include/linux/bits.h:5,
                    from include/linux/ratelimit_types.h:5,
                    from include/linux/printk.h:9,
                    from include/asm-generic/bug.h:22,
                    from arch/alpha/include/asm/bug.h:23,
                    from include/linux/bug.h:5,
                    from include/linux/vfsdebug.h:5,
                    from include/linux/fs.h:5,
                    from include/linux/debugfs.h:15,
                    from mm/zblock.c:20:
   mm/zblock.h:44:40: error: 'SLOT_BITS' undeclared here (not in a function); did you mean 'SLOT_SIZE'?
      44 |         DECLARE_BITMAP(slot_info, 1 << SLOT_BITS);
         |                                        ^~~~~~~~~
   include/uapi/linux/const.h:51:40: note: in definition of macro '__KERNEL_DIV_ROUND_UP'
      51 | #define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
         |                                        ^
   include/linux/types.h:11:28: note: in expansion of macro 'BITS_TO_LONGS'
      11 |         unsigned long name[BITS_TO_LONGS(bits)]
         |                            ^~~~~~~~~~~~~
   mm/zblock.h:44:9: note: in expansion of macro 'DECLARE_BITMAP'
      44 |         DECLARE_BITMAP(slot_info, 1 << SLOT_BITS);
         |         ^~~~~~~~~~~~~~
   mm/zblock.c: In function 'zblock_blocks_show':
>> mm/zblock.c:125:66: error: 'const struct block_desc' has no member named 'num_pages'
     125 |                         i, block_list->block_count, block_desc[i].num_pages,
         |                                                                  ^
   mm/zblock.c:126:64: error: 'const struct block_desc' has no member named 'num_pages'
     126 |                         block_list->block_count * block_desc[i].num_pages);
         |                                                                ^


vim +125 mm/zblock.c

   115	
   116	static int zblock_blocks_show(struct seq_file *s, void *v)
   117	{
   118		struct zblock_pool *pool = s->private;
   119		int i;
   120	
   121		for (i = 0; i < ARRAY_SIZE(block_desc); i++) {
   122			struct block_list *block_list = &pool->block_lists[i];
   123	
   124			seq_printf(s, "%d: %ld blocks of %d pages (total %ld pages)\n",
 > 125				i, block_list->block_count, block_desc[i].num_pages,
   126				block_list->block_count * block_desc[i].num_pages);
   127		}
   128		return 0;
   129	}
   130	DEFINE_SHOW_ATTRIBUTE(zblock_blocks);
   131	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki