On Thu, 10 Feb 2011, Tao Ma wrote: > From: Tao Ma <boyu.mt@xxxxxxxxxx> > > 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/sdb2 108G 35G 68G 34% /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 test]# time ./ftrim /mnt/ext4/a > real 0m4.039s > user 0m0.000s > sys 0m1.020s > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m3.577s > user 0m0.001s > sys 0m1.004s > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m3.380s > user 0m0.000s > sys 0m0.991s > > with the patch: > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m3.466s > user 0m0.000s > sys 0m0.966s > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m0.001s > user 0m0.000s > sys 0m0.001s > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m0.001s > user 0m0.000s > sys 0m0.000s > > A big improvement for the 2nd and 3rd run. > > After I delete some big image files and re-run the trim, > it is still much faster than iterating the whole disk. > /dev/sdb2 108G 25G 78G 24% /mnt/ext4 > > [root@boyu-tm test]# time ./ftrim /mnt/ext4/a > real 0m0.513s > user 0m0.000s > sys 0m0.069s Great it looks really good. > > Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx> > Cc: Lukas Czerner <lczerner@xxxxxxxxxx> > Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> > --- > fs/ext4/ext4.h | 8 +++++++- > fs/ext4/mballoc.c | 22 ++++++++++++++++++++++ > 2 files changed, 29 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 0c8d97b..1d59a63 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1200,6 +1200,9 @@ struct ext4_sb_info { > struct ext4_li_request *s_li_request; > /* Wait multiplier for lazy initialization thread */ > unsigned int s_li_wait_mult; > + > + /* record the last minlen when FITRIM is called. */ > + u64 s_last_trim_minblks; > }; > > static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb) > @@ -1970,10 +1973,13 @@ 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_HAS_BEEN_TRIMMED(grp) \ > + (test_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 4eadac8..c7aa094 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -2687,6 +2687,16 @@ 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)) > + clear_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, > + &(db->bb_state)); > + > if (!db->bb_free_root.rb_node) { > /* No more items in the per group rb tree > * balance refcounts from ext4_mb_free_metadata() > @@ -4772,6 +4782,10 @@ ext4_grpblk_t ext4_trim_all_free(struct super_block *sb, struct ext4_buddy *e4b, > > ext4_lock_group(sb, group); > > + if (EXT4_MB_GRP_HAS_BEEN_TRIMMED(e4b->bd_info) && > + minblocks >= EXT4_SB(sb)->s_last_trim_minblks) > + goto out; > + > trace_ext4_trim_all_free(sb, group, start, max); > > while (start < max) { > @@ -4804,6 +4818,11 @@ ext4_grpblk_t ext4_trim_all_free(struct super_block *sb, struct ext4_buddy *e4b, > if ((e4b->bd_info->bb_free - free_count) < minblocks) > break; > } > + > + if (!ret) > + set_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, > + &(e4b->bd_info->bb_state)); > +out: > ext4_unlock_group(sb, group); > > ext4_debug("trimmed %d blocks in the group %d\n", > @@ -4892,6 +4911,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) > } > range->len = trimmed * sb->s_blocksize; > > + if (!ret) > + EXT4_SB(sb)->s_last_trim_minblks = minlen; > + Since this is not protected by any lock, would not it race in case of multiple FITRIM calls ? > out: > return ret; > } > Thanks! -Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html