From patchwork Mon Dec 10 03:01:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "jianchao.wang" X-Patchwork-Id: 10720561 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 792B31759 for ; Mon, 10 Dec 2018 03:02:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 69B3329CE3 for ; Mon, 10 Dec 2018 03:02:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5E37329CE9; Mon, 10 Dec 2018 03:02:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D62C029CE3 for ; Mon, 10 Dec 2018 03:02:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726451AbeLJDCZ (ORCPT ); Sun, 9 Dec 2018 22:02:25 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:54510 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726481AbeLJDCQ (ORCPT ); Sun, 9 Dec 2018 22:02:16 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wBA2x93X131725; Mon, 10 Dec 2018 03:02:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2018-07-02; bh=btd6DoZkoF/8oWAYNuzBIPI636kyajQBCG9lJ6o/hTw=; b=Tl9KoJkxkukGZQy70ZN7Rlx2zosgmHnZ8AixdiuR28cr8vq3H/BDPMYDQPs+SMrgKgtl KtoAYaCGjgE07S1IgWxUXJPApipeXbalKU9dW9ZA63AKcpkCuD9u3TsfDRF5YjSvatRX J3YpBGydGUGHpVGOTRjxn00sG1UnF+UBiyzMxRVLGoy9lCnF+BcV0IkaOns8p82X8Z/W IJMODMGCWvgbqpft3WZWAJ4YEwPYUVmaf7SIdCuRsmg0/23+EvYIuPJMawXLm5rGKe2J Tm56QBPLpgNZ7jZJ7naz0dk+em1GN7Zh3ZKqCVMBcoc+ITjfON7RToXhk3abG/qC60gT Lg== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2p86kqkdje-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 10 Dec 2018 03:02:13 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wBA326gf001877 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 10 Dec 2018 03:02:07 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wBA326nQ012671; Mon, 10 Dec 2018 03:02:06 GMT Received: from will-ThinkCentre-M93p.cn.oracle.com (/10.182.70.234) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 09 Dec 2018 19:02:06 -0800 From: Jianchao Wang To: axboe@kernel.dk Cc: ming.lei@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V13 1/3] blk-mq: refactor the code of issue request directly Date: Mon, 10 Dec 2018 11:01:30 +0800 Message-Id: <1544410892-2905-2-git-send-email-jianchao.w.wang@oracle.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1544410892-2905-1-git-send-email-jianchao.w.wang@oracle.com> References: <1544410892-2905-1-git-send-email-jianchao.w.wang@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9102 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812100026 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly into one interface to unify the interfaces to issue requests directly. The merged interface takes over the requests totally, it could insert, end or do nothing based on the return value of .queue_rq and 'bypass' parameter. Then caller needn't any other handling any more and then code could be cleaned up. Signed-off-by: Jianchao Wang --- block/blk-mq.c | 103 ++++++++++++++++++++++++++++++--------------------------- 1 file changed, 54 insertions(+), 49 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index b645275..8dc34d2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1794,78 +1794,83 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, return ret; } -static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, +static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie, - bool bypass_insert, bool last) + bool bypass, bool last) { struct request_queue *q = rq->q; bool run_queue = true; + blk_status_t ret = BLK_STS_RESOURCE; + int srcu_idx; + bool force = false; + hctx_lock(hctx, &srcu_idx); /* - * RCU or SRCU read lock is needed before checking quiesced flag. + * hctx_lock is needed before checking quiesced flag. * - * When queue is stopped or quiesced, ignore 'bypass_insert' from - * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, - * and avoid driver to try to dispatch again. + * When queue is stopped or quiesced, ignore 'bypass', insert + * and return BLK_STS_OK to caller, and avoid driver to try to + * dispatch again. */ - if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { + if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) { run_queue = false; - bypass_insert = false; - goto insert; + bypass = false; + goto out_unlock; } - if (q->elevator && !bypass_insert) - goto insert; + if (unlikely(q->elevator && !bypass)) + goto out_unlock; if (!blk_mq_get_dispatch_budget(hctx)) - goto insert; + goto out_unlock; if (!blk_mq_get_driver_tag(rq)) { blk_mq_put_dispatch_budget(hctx); - goto insert; + goto out_unlock; } - return __blk_mq_issue_directly(hctx, rq, cookie, last); -insert: - if (bypass_insert) - return BLK_STS_RESOURCE; - - blk_mq_request_bypass_insert(rq, run_queue); - return BLK_STS_OK; -} - -static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, - struct request *rq, blk_qc_t *cookie) -{ - blk_status_t ret; - int srcu_idx; - - might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); - - hctx_lock(hctx, &srcu_idx); - - ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true); - if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) - blk_mq_request_bypass_insert(rq, true); - else if (ret != BLK_STS_OK) - blk_mq_end_request(rq, ret); - + /* + * Always add a request that has been through + *.queue_rq() to the hardware dispatch list. + */ + force = true; + ret = __blk_mq_issue_directly(hctx, rq, cookie, last); +out_unlock: hctx_unlock(hctx, srcu_idx); + switch (ret) { + case BLK_STS_OK: + break; + case BLK_STS_DEV_RESOURCE: + case BLK_STS_RESOURCE: + if (force) { + blk_mq_request_bypass_insert(rq, run_queue); + /* + * We have to return BLK_STS_OK for the DM + * to avoid livelock. Otherwise, we return + * the real result to indicate whether the + * request is direct-issued successfully. + */ + ret = bypass ? BLK_STS_OK : ret; + } else if (!bypass) { + blk_mq_sched_insert_request(rq, false, + run_queue, false); + } + break; + default: + if (!bypass) + blk_mq_end_request(rq, ret); + break; + } + + return ret; } blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) { - blk_status_t ret; - int srcu_idx; - blk_qc_t unused_cookie; - struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + blk_qc_t unused; - hctx_lock(hctx, &srcu_idx); - ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last); - hctx_unlock(hctx, srcu_idx); - - return ret; + return blk_mq_try_issue_directly(rq->mq_hctx, rq, &unused, true, last); } void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, @@ -2006,13 +2011,13 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) if (same_queue_rq) { data.hctx = same_queue_rq->mq_hctx; blk_mq_try_issue_directly(data.hctx, same_queue_rq, - &cookie); + &cookie, false, true); } } else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator && !data.hctx->dispatch_busy)) { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); - blk_mq_try_issue_directly(data.hctx, rq, &cookie); + blk_mq_try_issue_directly(data.hctx, rq, &cookie, false, true); } else { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio);