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Commit d08854f5 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: optimize ext4_should_retry_alloc() to improve ENOSPC performance 



If there are no pending blocks to be released after a commit, forcing
a journal commit has no hope of helping.  It's possible that a commit
had just completed, so if there are now free blocks available for
allocation, it's worth retrying the commit.

Reported-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 1a695a90

fs/ext4/balloc.c

+3 −1
Original line number Diff line number Diff line
@@ -610,6 +610,8 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries) 


	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);



	smp_mb();

	if (EXT4_SB(sb)->s_mb_free_pending)

		jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);

	return 1;

}

fs/ext4/ext4.h

+1 −0
Original line number Diff line number Diff line
@@ -1430,6 +1430,7 @@ struct ext4_sb_info { 
	unsigned short *s_mb_offsets;

	unsigned int *s_mb_maxs;

	unsigned int s_group_info_size;

	unsigned int s_mb_free_pending;



	/* tunables */

	unsigned long s_stripe;

fs/ext4/ext4_jbd2.h

+9 −1
Original line number Diff line number Diff line
@@ -175,6 +175,13 @@ struct ext4_journal_cb_entry { 
 * There is no guaranteed calling order of multiple registered callbacks on

 * the same transaction.

 */

static inline void _ext4_journal_callback_add(handle_t *handle,

			struct ext4_journal_cb_entry *jce)

{

	/* Add the jce to transaction's private list */

	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);

}



static inline void ext4_journal_callback_add(handle_t *handle,

			void (*func)(struct super_block *sb,

				     struct ext4_journal_cb_entry *jce,
@@ -187,10 +194,11 @@ static inline void ext4_journal_callback_add(handle_t *handle, 
	/* Add the jce to transaction's private list */

	jce->jce_func = func;

	spin_lock(&sbi->s_md_lock);

	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);

	_ext4_journal_callback_add(handle, jce);

	spin_unlock(&sbi->s_md_lock);

}





/**

 * ext4_journal_callback_del: delete a registered callback

 * @handle: active journal transaction handle on which callback was registered

fs/ext4/mballoc.c

+10 −2
Original line number Diff line number Diff line
@@ -2627,6 +2627,7 @@ int ext4_mb_init(struct super_block *sb) 


	spin_lock_init(&sbi->s_md_lock);

	spin_lock_init(&sbi->s_bal_lock);

	sbi->s_mb_free_pending = 0;



	sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;

	sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
@@ -2814,6 +2815,9 @@ static void ext4_free_data_callback(struct super_block *sb, 
	/* we expect to find existing buddy because it's pinned */

	BUG_ON(err != 0);



	spin_lock(&EXT4_SB(sb)->s_md_lock);

	EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;

	spin_unlock(&EXT4_SB(sb)->s_md_lock);



	db = e4b.bd_info;

	/* there are blocks to put in buddy to make them really free */
@@ -4583,6 +4587,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, 
{

	ext4_group_t group = e4b->bd_group;

	ext4_grpblk_t cluster;

	ext4_grpblk_t clusters = new_entry->efd_count;

	struct ext4_free_data *entry;

	struct ext4_group_info *db = e4b->bd_info;

	struct super_block *sb = e4b->bd_sb;
@@ -4649,8 +4654,11 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, 
		}

	}

	/* Add the extent to transaction's private list */

	ext4_journal_callback_add(handle, ext4_free_data_callback,

				  &new_entry->efd_jce);

	new_entry->efd_jce.jce_func = ext4_free_data_callback;

	spin_lock(&sbi->s_md_lock);

	_ext4_journal_callback_add(handle, &new_entry->efd_jce);

	sbi->s_mb_free_pending += clusters;

	spin_unlock(&sbi->s_md_lock);

	return 0;

}