From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:19982 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751761AbbAGJVb (ORCPT ); Wed, 7 Jan 2015 04:21:31 -0500 Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t079LUDa027910 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 7 Jan 2015 09:21:31 GMT Received: from aserz7022.oracle.com (aserz7022.oracle.com [141.146.126.231]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id t079LU3j007543 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Wed, 7 Jan 2015 09:21:30 GMT Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserz7022.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id t079LT4V006437 for ; Wed, 7 Jan 2015 09:21:30 GMT From: Liu Bo To: linux-btrfs@vger.kernel.org Subject: [RFC PATCH] Btrfs: use asynchronous submit for large DIO io in single profile Date: Wed, 7 Jan 2015 17:21:12 +0800 Message-Id: <1420622472-9656-1-git-send-email-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: 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 --- fs/btrfs/inode.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e687bb0..c640d7e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -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; -- 1.8.1.4