@@ -7792,6 +7792,7 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
int nr_pages = 0;
int ret;
int async_submit = 0;
+ u64 alloc_profile;
map_length = orig_bio->bi_iter.bi_size;
ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
@@ -7799,15 +7800,26 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
if (ret)
return -EIO;
+ alloc_profile = btrfs_get_alloc_profile(root, 1);
+
if (map_length >= orig_bio->bi_iter.bi_size) {
bio = orig_bio;
dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
+
+ /*
+ * In the case of 'single' profile, the above check is very
+ * likely to be true as map_length is (chunk_length - offset),
+ * so checking BTRFS_STRIPE_LEN here.
+ */
+ if ((alloc_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
+ orig_bio->bi_iter.bi_size >= BTRFS_STRIPE_LEN)
+ async_submit = 1;
+
goto submit;
}
/* async crcs make it difficult to collect full stripe writes. */
- if (btrfs_get_alloc_profile(root, 1) &
- (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
+ if (alloc_profile & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
async_submit = 0;
else
async_submit = 1;
Commit 1ae399382512 ("Btrfs: do not use async submit for small DIO io's") benefits small DIO io's. However, if we're owning the SINGLE profile, this also affects large DIO io's since in that case, map_length is (chunk_length - bio's offset_in_chunk), it's farily large so that it's very likely to be larger than a large bio's size, which avoids asynchronous submit. For instance, if we have a 512k bio, the efforts of calculating (512k/4k=128) checksums will be taken by the DIO task. This adds a limit 'BTRFS_STRIPE_LEN' to decide if it's small enough to avoid asynchronous submit. Still, in this case we don't need to split the bio and can submit it directly. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/inode.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)