From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2172C433FE for ; Fri, 8 Apr 2022 07:24:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229937AbiDHH0y (ORCPT ); Fri, 8 Apr 2022 03:26:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbiDHH0q (ORCPT ); Fri, 8 Apr 2022 03:26:46 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5301D36A451; Fri, 8 Apr 2022 00:24:43 -0700 (PDT) Received: from kwepemi100003.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4KZV9m2SBdzdZgB; Fri, 8 Apr 2022 15:24:12 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100003.china.huawei.com (7.221.188.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 8 Apr 2022 15:24:41 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 8 Apr 2022 15:24:40 +0800 From: Yu Kuai To: , , , , CC: , , Subject: [PATCH -next RFC v2 6/8] blk-mq: force tag preemption for split bios Date: Fri, 8 Apr 2022 15:39:14 +0800 Message-ID: <20220408073916.1428590-7-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220408073916.1428590-1-yukuai3@huawei.com> References: <20220408073916.1428590-1-yukuai3@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org For HDD, sequential io is much faster than random io, thus it's better to issue split io continuously. However, this is broken when tag preemption is disabled, because wakers can only get one tag each time. Thus tag preemption should be disabled for split bios, specifically the first bio won't preempt tag, and following split bios will preempt tag. Signed-off-by: Yu Kuai --- block/blk-merge.c | 9 ++++++++- block/blk-mq.c | 1 + include/linux/blk_types.h | 4 ++++ 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 7771dacc99cb..cab6ca681513 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -343,12 +343,19 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio, if (split) { /* there isn't chance to merge the splitted bio */ - split->bi_opf |= REQ_NOMERGE; + split->bi_opf |= (REQ_NOMERGE | REQ_SPLIT); + if ((*bio)->bi_opf & REQ_SPLIT) + split->bi_opf |= REQ_PREEMPT; + else + (*bio)->bi_opf |= REQ_SPLIT; bio_chain(split, *bio); trace_block_split(split, (*bio)->bi_iter.bi_sector); submit_bio_noacct(*bio); *bio = split; + } else { + if ((*bio)->bi_opf & REQ_SPLIT) + (*bio)->bi_opf |= REQ_PREEMPT; } } diff --git a/block/blk-mq.c b/block/blk-mq.c index ed3ed86f7dd2..909420c5186c 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2737,6 +2737,7 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, .q = q, .nr_tags = 1, .cmd_flags = bio->bi_opf, + .preemption = (bio->bi_opf & REQ_PREEMPT), }; struct request *rq; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index c62274466e72..6b56e271f926 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -418,6 +418,8 @@ enum req_flag_bits { /* for driver use */ __REQ_DRV, __REQ_SWAP, /* swapping request. */ + __REQ_SPLIT, + __REQ_PREEMPT, __REQ_NR_BITS, /* stops here */ }; @@ -443,6 +445,8 @@ enum req_flag_bits { #define REQ_DRV (1ULL << __REQ_DRV) #define REQ_SWAP (1ULL << __REQ_SWAP) +#define REQ_SPLIT (1ULL << __REQ_SPLIT) +#define REQ_PREEMPT (1ULL << __REQ_PREEMPT) #define REQ_FAILFAST_MASK \ (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER) -- 2.31.1