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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c1ab3ec..77249e1 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2627,6 +2627,7 @@
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 @@
/* 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_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 @@
}
}
/* 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;
}