[PATCH] ext4: optimize ext4_should_retry_alloc() to improve ENOSPC performance
From: Theodore Ts'o <tytso@mit.edu>
Date: 2016-06-08 02:37:03
If there are pending blocks to be released after a commit, retrying the allocation after a journal commit has no hope of helping. So track how many pending deleted blocks there might be, and don't retry if there are no pending blocks. Reported-by: Chao Yu <redacted> Signed-off-by: Theodore Ts'o <tytso@mit.edu> --- fs/ext4/balloc.c | 9 ++++++++- fs/ext4/ext4.h | 1 + fs/ext4/ext4_jbd2.h | 10 +++++++++- fs/ext4/fsync.c | 5 +++-- fs/ext4/mballoc.c | 12 ++++++++++-- 5 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 3020fd7..371ac63 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c@@ -603,7 +603,14 @@ int ext4_claim_free_clusters(struct ext4_sb_info *sbi, */ int ext4_should_retry_alloc(struct super_block *sb, int *retries) { - if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || + unsigned int pending_blocks; + + spin_lock(&EXT4_SB(sb)->s_md_lock); + pending_blocks = EXT4_SB(sb)->s_mb_free_pending; + spin_unlock(&EXT4_SB(sb)->s_md_lock); + + if (pending_blocks == 0 || + !ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || (*retries)++ > 3 || !EXT4_SB(sb)->s_journal) return 0;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b84aa1c..96c73e6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h@@ -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;
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 09c1ef3..b1d52c1 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h@@ -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
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 8850254..7ee4abd 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c@@ -106,10 +106,10 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) } if (!journal) { - ret = generic_file_fsync(file, start, end, datasync); + ret = __generic_file_fsync(file, start, end, datasync); if (!ret && !hlist_empty(&inode->i_dentry)) ret = ext4_sync_parent(inode); - goto out; + goto issue_flush; } ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
@@ -140,6 +140,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) needs_barrier = true; ret = jbd2_complete_transaction(journal, commit_tid); if (needs_barrier) { + issue_flush: err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); if (!ret) ret = err;
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 @@ 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; }
--
2.5.0