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authorTao Ma <boyu.mt@taobao.com>2011-07-11 00:03:38 -0400
committerTheodore Ts'o <tytso@mit.edu>2011-07-11 00:03:38 -0400
commit3d56b8d2c74cc3f375ce332b3ac3519e009d79ee (patch)
tree47c13dc80779a3d8d93902897a500b056375689c
parentb3d4c2b10b68d205d3eb1b5c17dcb4649a502798 (diff)
ext4: Speed up FITRIM by recording flags in ext4_group_info
In ext4, when FITRIM is called every time, we iterate all the groups and do trim one by one. It is a bit time wasting if the group has been trimmed and there is no change since the last trim. So this patch adds a new flag in ext4_group_info->bb_state to indicate that the group has been trimmed, and it will be cleared if some blocks is freed(in release_blocks_on_commit). Another trim_minlen is added in ext4_sb_info to record the last minlen we use to trim the volume, so that if the caller provide a small one, we will go on the trim regardless of the bb_state. A simple test with my intel x25m ssd: df -h shows: /dev/sdb1 40G 21G 17G 56% /mnt/ext4 Block size: 4096 run the FITRIM with the following parameter: range.start = 0; range.len = UINT64_MAX; range.minlen = 1048576; without the patch: [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m5.505s user 0m0.000s sys 0m1.224s [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m5.359s user 0m0.000s sys 0m1.178s [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m5.228s user 0m0.000s sys 0m1.151s with the patch: [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m5.625s user 0m0.000s sys 0m1.269s [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m0.002s user 0m0.000s sys 0m0.001s [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a real 0m0.002s user 0m0.000s sys 0m0.001s A big improvement for the 2nd and 3rd run. Even after I delete some big image files, it is still much faster than iterating the whole disk. [root@boyu-tm test]# time ./ftrim /mnt/ext4/a real 0m1.217s user 0m0.000s sys 0m0.196s Cc: Lukas Czerner <lczerner@redhat.com> Reviewed-by: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/ext4.h13
-rw-r--r--fs/ext4/mballoc.c20
2 files changed, 32 insertions, 1 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d13f3b50988..62cee2b6fe7 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1215,6 +1215,9 @@ struct ext4_sb_info {
/* Kernel thread for multiple mount protection */
struct task_struct *s_mmp_tsk;
+
+ /* record the last minlen when FITRIM is called. */
+ atomic_t s_last_trim_minblks;
};
static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
@@ -2080,11 +2083,19 @@ struct ext4_group_info {
* 5 free 8-block regions. */
};
-#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
+#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
+#define EXT4_GROUP_INFO_WAS_TRIMMED_BIT 1
#define EXT4_MB_GRP_NEED_INIT(grp) \
(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_WAS_TRIMMED(grp) \
+ (test_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_SET_TRIMMED(grp) \
+ (set_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_CLEAR_TRIMMED(grp) \
+ (clear_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
+
#define EXT4_MAX_CONTENTION 8
#define EXT4_CONTENTION_THRESHOLD 2
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7aa4c16caca..73c254085a4 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2628,6 +2628,15 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
rb_erase(&entry->node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count);
+ /*
+ * Clear the trimmed flag for the group so that the next
+ * ext4_trim_fs can trim it.
+ * If the volume is mounted with -o discard, online discard
+ * is supported and the free blocks will be trimmed online.
+ */
+ if (!test_opt(sb, DISCARD))
+ EXT4_MB_GRP_CLEAR_TRIMMED(db);
+
if (!db->bb_free_root.rb_node) {
/* No more items in the per group rb tree
* balance refcounts from ext4_mb_free_metadata()
@@ -4838,6 +4847,10 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
bitmap = e4b.bd_bitmap;
ext4_lock_group(sb, group);
+ if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
+ minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
+ goto out;
+
start = (e4b.bd_info->bb_first_free > start) ?
e4b.bd_info->bb_first_free : start;
@@ -4869,6 +4882,10 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
if ((e4b.bd_info->bb_free - free_count) < minblocks)
break;
}
+
+ if (!ret)
+ EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
+out:
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
@@ -4957,6 +4974,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
}
range->len = trimmed * sb->s_blocksize;
+ if (!ret)
+ atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
+
out:
return ret;
}