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ext4: optimize ext4_should_retry_alloc() to improve ENOSPC performance

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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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2016-06-26 18:24:01 -04:00
parent 1a695a905c
commit d08854f5bc
4 changed files with 23 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/ext4/balloc.c
View File

@ -610,7 +610,9 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
smp_mb();
if (EXT4_SB(sb)->s_mb_free_pending)
jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
return 1;
}

1
fs/ext4/ext4.h
View File

@ -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;

10
fs/ext4/ext4_jbd2.h
View File

@ -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

12
fs/ext4/mballoc.c
View File

@ -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;
}