@@ -5083,9 +5083,9 @@ static void init_alloc_chunk_ctl_policy_regular(
if (ctl->type & BTRFS_BLOCK_GROUP_SYSTEM)
ctl->devs_max = min_t(int, ctl->devs_max, BTRFS_MAX_DEVS_SYS_CHUNK);
- /* We don't want a chunk larger than 10% of writable space */
- ctl->max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
- ctl->max_chunk_size);
+ /* We don't want a chunk larger than 1/8 of writable space */
+ ctl->max_chunk_size = min_t(u64, ctl->max_chunk_size,
+ rounddown_pow_of_two(fs_devices->total_rw_bytes >> 3));
ctl->dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
}
@@ -5143,10 +5143,9 @@ static void init_alloc_chunk_ctl_policy_zoned(
BUG();
}
- /* We don't want a chunk larger than 10% of writable space */
- limit = max(round_down(div_factor(fs_devices->total_rw_bytes, 1),
- zone_size),
- min_chunk_size);
+ /* We don't want a chunk larger than 1/8 of writable space */
+ limit = max_t(u64, min_chunk_size,
+ rounddown_pow_of_two(fs_devices->total_rw_bytes >> 3));
ctl->max_chunk_size = min(limit, ctl->max_chunk_size);
ctl->dev_extent_min = zone_size * ctl->dev_stripes;
}
@@ -5284,13 +5283,12 @@ static int decide_stripe_size_regular(struct alloc_chunk_ctl *ctl,
*/
if (ctl->stripe_size * data_stripes > ctl->max_chunk_size) {
/*
- * Reduce stripe_size, round it up to a 16MB boundary again and
+ * Reduce stripe_size, round it up to pow of 2 boundary again and
* then use it, unless it ends up being even bigger than the
* previous value we had already.
*/
- ctl->stripe_size = min(round_up(div_u64(ctl->max_chunk_size,
- data_stripes), SZ_16M),
- ctl->stripe_size);
+ ctl->stripe_size = min_t(u64, ctl->stripe_size,
+ roundup_pow_of_two(div_u64(ctl->max_chunk_size, data_stripes)));
}
/* Align to BTRFS_STRIPE_LEN */
In decide_stripe_size_regular(), when new disk is added to RAID0/RAID10/RAID56, it is better to alloc/free-then-reuse the free space if stripe size is kept or changed to 1/2. so stripe size of pow of 2 will be more friendly. In a rare case that file system is quite small, we calc max chunk size in pow of 2 too, so that max chunk size / chunk size /stripe size are same or match easy. Signed-off-by: Wang Yugui <wangyugui@e16-tech.com> --- changes since v1: - change rounddown_pow_of_two() to roundup_pow_of_two() to match better with orig roundup(). fs/btrfs/volumes.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)