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Message-Id: <1309445439-3753-4-git-send-email-tm@tao.ma>
Date: Thu, 30 Jun 2011 22:50:39 +0800
From: Tao Ma <tm@....ma>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu
Subject: [PATCH 4/4] ext4: Speed up FITRIM by recording flags in ext4_group_info.
From: Tao Ma <boyu.mt@...bao.com>
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@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
real 0m5.505s
user 0m0.000s
sys 0m1.224s
[root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
real 0m5.359s
user 0m0.000s
sys 0m1.178s
[root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
real 0m5.228s
user 0m0.000s
sys 0m1.151s
with the patch:
[root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
real 0m5.625s
user 0m0.000s
sys 0m1.269s
[root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
real 0m0.002s
user 0m0.000s
sys 0m0.001s
[root@...u-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@...u-tm test]# time ./ftrim /mnt/ext4/a
real 0m1.217s
user 0m0.000s
sys 0m0.196s
Reviewed-by: Andreas Dilger <adilger.kernel@...ger.ca>
Signed-off-by: Tao Ma <boyu.mt@...bao.com>
---
fs/ext4/ext4.h | 13 ++++++++++++-
fs/ext4/mballoc.c | 20 ++++++++++++++++++++
fs/ext4/super.c | 2 ++
3 files changed, 34 insertions(+), 1 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1921392..5878a22 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1214,6 +1214,9 @@ 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)
@@ -2067,11 +2070,19 @@ 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 a822f2a..afdd869 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()
@@ -4840,6 +4849,10 @@ 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;
@@ -4871,6 +4884,10 @@ 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);
@@ -4960,6 +4977,9 @@ 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;
}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9ea71aa..080e9f9 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3086,6 +3086,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
sbi->s_sectors_written_start =
part_stat_read(sb->s_bdev->bd_part, sectors[1]);
+ atomic_set(&sbi->s_last_trim_minblks, 0);
+
/* Cleanup superblock name */
for (cp = sb->s_id; (cp = strchr(cp, '/'));)
*cp = '!';
--
1.7.4
--
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