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Commit 6ba495e9 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Add configurable run-time mballoc debugging 



Allow mballoc debugging to be enabled at run-time instead of just at
compile time.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 91cc219a

fs/ext4/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -77,3 +77,12 @@ config EXT4_FS_SECURITY 


	  If you are not using a security module that requires using

	  extended attributes for file security labels, say N.



config EXT4_DEBUG

	bool "EXT4 debugging support"

	depends on EXT4_FS

	help

	  Enables run-time debugging support for the ext4 filesystem.



	  If you select Y here, then you will be able to turn on debugging

	  with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug"

fs/ext4/mballoc.c

+59 −22
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
 */



#include "mballoc.h"

#include <linux/debugfs.h>

#include <trace/events/ext4.h>



/*
@@ -743,7 +744,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) 
	char *data;

	char *bitmap;



	mb_debug("init page %lu\n", page->index);

	mb_debug(1, "init page %lu\n", page->index);



	inode = page->mapping->host;

	sb = inode->i_sb;
@@ -822,7 +823,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) 
		set_bitmap_uptodate(bh[i]);

		bh[i]->b_end_io = end_buffer_read_sync;

		submit_bh(READ, bh[i]);

		mb_debug("read bitmap for group %u\n", first_group + i);

		mb_debug(1, "read bitmap for group %u\n", first_group + i);

	}



	/* wait for I/O completion */
@@ -862,7 +863,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) 
		if ((first_block + i) & 1) {

			/* this is block of buddy */

			BUG_ON(incore == NULL);

			mb_debug("put buddy for group %u in page %lu/%x\n",

			mb_debug(1, "put buddy for group %u in page %lu/%x\n",

				group, page->index, i * blocksize);

			grinfo = ext4_get_group_info(sb, group);

			grinfo->bb_fragments = 0;
@@ -878,7 +879,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) 
		} else {

			/* this is block of bitmap */

			BUG_ON(incore != NULL);

			mb_debug("put bitmap for group %u in page %lu/%x\n",

			mb_debug(1, "put bitmap for group %u in page %lu/%x\n",

				group, page->index, i * blocksize);



			/* see comments in ext4_mb_put_pa() */
@@ -922,7 +923,7 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, 
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	struct inode *inode = sbi->s_buddy_cache;



	mb_debug("load group %u\n", group);

	mb_debug(1, "load group %u\n", group);



	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;

	grp = ext4_get_group_info(sb, group);
@@ -1851,7 +1852,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group) 
	struct inode *inode = sbi->s_buddy_cache;

	struct page *page = NULL, *bitmap_page = NULL;



	mb_debug("init group %u\n", group);

	mb_debug(1, "init group %u\n", group);

	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;

	this_grp = ext4_get_group_info(sb, group);

	/*
@@ -2739,7 +2740,7 @@ static void ext4_mb_cleanup_pa(struct ext4_group_info *grp) 
		kmem_cache_free(ext4_pspace_cachep, pa);

	}

	if (count)

		mb_debug("mballoc: %u PAs left\n", count);

		mb_debug(1, "mballoc: %u PAs left\n", count);



}
@@ -2820,7 +2821,7 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) 
	list_for_each_safe(l, ltmp, &txn->t_private_list) {

		entry = list_entry(l, struct ext4_free_data, list);



		mb_debug("gonna free %u blocks in group %u (0x%p):",

		mb_debug(1, "gonna free %u blocks in group %u (0x%p):",

			 entry->count, entry->group, entry);



		err = ext4_mb_load_buddy(sb, entry->group, &e4b);
@@ -2855,9 +2856,43 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) 
		ext4_mb_release_desc(&e4b);

	}



	mb_debug("freed %u blocks in %u structures\n", count, count2);

	mb_debug(1, "freed %u blocks in %u structures\n", count, count2);

}



#ifdef CONFIG_EXT4_DEBUG

u8 mb_enable_debug __read_mostly;



static struct dentry *debugfs_dir;

static struct dentry *debugfs_debug;



static void __init ext4_create_debugfs_entry(void)

{

	debugfs_dir = debugfs_create_dir("ext4", NULL);

	if (debugfs_dir)

		debugfs_debug = debugfs_create_u8("mballoc-debug",

						  S_IRUGO | S_IWUSR,

						  debugfs_dir,

						  &mb_enable_debug);

}



static void ext4_remove_debugfs_entry(void)

{

	debugfs_remove(debugfs_debug);

	debugfs_remove(debugfs_dir);

}



#else



static void __init ext4_create_debugfs_entry(void)

{

}



static void ext4_remove_debugfs_entry(void)

{

}



#endif



int __init init_ext4_mballoc(void)

{

	ext4_pspace_cachep =
@@ -2885,6 +2920,7 @@ int __init init_ext4_mballoc(void) 
		kmem_cache_destroy(ext4_ac_cachep);

		return -ENOMEM;

	}

	ext4_create_debugfs_entry();

	return 0;

}
@@ -2898,6 +2934,7 @@ void exit_ext4_mballoc(void) 
	kmem_cache_destroy(ext4_pspace_cachep);

	kmem_cache_destroy(ext4_ac_cachep);

	kmem_cache_destroy(ext4_free_ext_cachep);

	ext4_remove_debugfs_entry();

}
@@ -3042,7 +3079,7 @@ static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) 
		ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;

	else

		ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;

	mb_debug("#%u: goal %u blocks for locality group\n",

	mb_debug(1, "#%u: goal %u blocks for locality group\n",

		current->pid, ac->ac_g_ex.fe_len);

}
@@ -3232,7 +3269,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, 
		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;

	}



	mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size,

	mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,

		(unsigned) orig_size, (unsigned) start);

}
@@ -3281,7 +3318,7 @@ static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac, 
	BUG_ON(pa->pa_free < len);

	pa->pa_free -= len;



	mb_debug("use %llu/%u from inode pa %p\n", start, len, pa);

	mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);

}



/*
@@ -3305,7 +3342,7 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, 
	 * in on-disk bitmap -- see ext4_mb_release_context()

	 * Other CPUs are prevented from allocating from this pa by lg_mutex

	 */

	mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);

	mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);

}



/*
@@ -3484,7 +3521,7 @@ void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, 
		preallocated += len;

		count++;

	}

	mb_debug("prellocated %u for group %u\n", preallocated, group);

	mb_debug(1, "prellocated %u for group %u\n", preallocated, group);

}



static void ext4_mb_pa_callback(struct rcu_head *head)
@@ -3619,7 +3656,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) 
	pa->pa_deleted = 0;

	pa->pa_type = MB_INODE_PA;



	mb_debug("new inode pa %p: %llu/%u for %u\n", pa,

	mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,

			pa->pa_pstart, pa->pa_len, pa->pa_lstart);

	trace_ext4_mb_new_inode_pa(ac, pa);
@@ -3679,7 +3716,7 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac) 
	pa->pa_deleted = 0;

	pa->pa_type = MB_GROUP_PA;



	mb_debug("new group pa %p: %llu/%u for %u\n", pa,

	mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,

			pa->pa_pstart, pa->pa_len, pa->pa_lstart);

	trace_ext4_mb_new_group_pa(ac, pa);
@@ -3758,7 +3795,7 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh, 
		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);

		start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +

				le32_to_cpu(sbi->s_es->s_first_data_block);

		mb_debug("    free preallocated %u/%u in group %u\n",

		mb_debug(1, "    free preallocated %u/%u in group %u\n",

				(unsigned) start, (unsigned) next - bit,

				(unsigned) group);

		free += next - bit;
@@ -3849,7 +3886,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb, 
	int busy = 0;

	int free = 0;



	mb_debug("discard preallocation for group %u\n", group);

	mb_debug(1, "discard preallocation for group %u\n", group);



	if (list_empty(&grp->bb_prealloc_list))

		return 0;
@@ -3973,7 +4010,7 @@ void ext4_discard_preallocations(struct inode *inode) 
		return;

	}



	mb_debug("discard preallocation for inode %lu\n", inode->i_ino);

	mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);

	trace_ext4_discard_preallocations(inode);



	INIT_LIST_HEAD(&list);
@@ -4078,7 +4115,7 @@ static void ext4_mb_return_to_preallocation(struct inode *inode, 
{

	BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list));

}

#ifdef MB_DEBUG

#ifdef CONFIG_EXT4_DEBUG

static void ext4_mb_show_ac(struct ext4_allocation_context *ac)

{

	struct super_block *sb = ac->ac_sb;
@@ -4227,7 +4264,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac, 
	 * locality group. this is a policy, actually */

	ext4_mb_group_or_file(ac);



	mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "

	mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "

			"left: %u/%u, right %u/%u to %swritable\n",

			(unsigned) ar->len, (unsigned) ar->logical,

			(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
@@ -4249,7 +4286,7 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb, 
	struct ext4_prealloc_space *pa, *tmp;

	struct ext4_allocation_context *ac;



	mb_debug("discard locality group preallocation\n");

	mb_debug(1, "discard locality group preallocation\n");



	INIT_LIST_HEAD(&discard_list);

	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);

fs/ext4/mballoc.h

+12 −4
Original line number Diff line number Diff line
@@ -37,11 +37,19 @@ 


/*

 */

#define MB_DEBUG__

#ifdef MB_DEBUG

#define mb_debug(fmt, a...)	printk(fmt, ##a)

#ifdef CONFIG_EXT4_DEBUG

extern u8 mb_enable_debug;



#define mb_debug(n, fmt, a...)	                                        \

	do {								\

		if ((n) <= mb_enable_debug) {		        	\

			printk(KERN_DEBUG "(%s, %d): %s: ",		\

			       __FILE__, __LINE__, __func__);		\

			printk(fmt, ## a);				\

		}							\

	} while (0)

#else

#define mb_debug(fmt, a...)

#define mb_debug(n, fmt, a...)

#endif



/*