From patchwork Tue Oct 18 21:50:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 9383119 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8A0006086B for ; Tue, 18 Oct 2016 21:50:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7E5E0296C2 for ; Tue, 18 Oct 2016 21:50:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 72E5129769; Tue, 18 Oct 2016 21:50:38 +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=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable 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 CE442297E9 for ; Tue, 18 Oct 2016 21:50:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756049AbcJRVuf (ORCPT ); Tue, 18 Oct 2016 17:50:35 -0400 Received: from mail-cys01nam02on0062.outbound.protection.outlook.com ([104.47.37.62]:5767 "EHLO NAM02-CY1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754138AbcJRVuc (ORCPT ); Tue, 18 Oct 2016 17:50:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sandiskcorp.onmicrosoft.com; s=selector1-sandisk-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=KUgKM4d8e4fNw1hAiPb7nzHBFpDjTCyJ+VrZAJGYKQU=; b=rpYBNetKuZbLdNYdKxm/PRdAHbOXQAl5uVcSiL5OpteLZzykUsNQVEcK6jUVQbbhQyK7b8pFaAvy2YwAxZx659bkYDnTxGIUgwkCJ/yzo5HUXV6tQRfseM/pYFnv87Yq/hBZ+mLUkaupUOBJYP+97OAMHYXpXQ8AE+5U5pf53u8= Received: from DM5PR02CA0062.namprd02.prod.outlook.com (10.168.192.24) by BY2PR0201MB1910.namprd02.prod.outlook.com (10.163.75.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.16; Tue, 18 Oct 2016 21:50:30 +0000 Received: from BN1BFFO11FD025.protection.gbl (2a01:111:f400:7c10::1:181) by DM5PR02CA0062.outlook.office365.com (2603:10b6:3:39::24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.16 via Frontend Transport; Tue, 18 Oct 2016 21:50:29 +0000 Authentication-Results: spf=pass (sender IP is 63.163.107.21) smtp.mailfrom=sandisk.com; redhat.com; dkim=none (message not signed) header.d=none;redhat.com; dmarc=bestguesspass action=none header.from=sandisk.com; Received-SPF: Pass (protection.outlook.com: domain of sandisk.com designates 63.163.107.21 as permitted sender) receiver=protection.outlook.com; client-ip=63.163.107.21; helo=milsmgep15.sandisk.com; Received: from milsmgep15.sandisk.com (63.163.107.21) by BN1BFFO11FD025.mail.protection.outlook.com (10.58.144.88) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.7 via Frontend Transport; Tue, 18 Oct 2016 21:50:28 +0000 Received: from MILHUBIP04.sdcorp.global.sandisk.com (Unknown_Domain [10.201.67.162]) (using TLS with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by (Symantec Messaging Gateway) with SMTP id EC.CD.26959.2A696085; Tue, 18 Oct 2016 14:39:46 -0700 (PDT) Received: from milsmgip12.sandisk.com (10.177.8.100) by MILHUBIP04.sdcorp.global.sandisk.com (10.177.9.97) with Microsoft SMTP Server id 14.3.319.2; Tue, 18 Oct 2016 14:50:25 -0700 X-AuditID: 0ac94369-ef8199800001694f-3f-580696a24880 Received: from exp-402881.sandisk.com ( [10.177.9.6]) by (Symantec Messaging Gateway) with SMTP id 4D.A3.03615.12996085; Tue, 18 Oct 2016 14:50:25 -0700 (PDT) Subject: [PATCH v3 04/11] blk-mq: Introduce blk_mq_quiesce_queue() To: Jens Axboe References: CC: Christoph Hellwig , James Bottomley , "Martin K. Petersen" , Mike Snitzer , Doug Ledford , Keith Busch , Ming Lin , Laurence Oberman , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" From: Bart Van Assche Message-ID: Date: Tue, 18 Oct 2016 14:50:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrPIsWRmVeSWpSXmKPExsXCddJ5ke6iaWwRBt8OaFn833OMzeLl+Q+s FitXH2WyWDUxz+Le0S9MFntvaVvMX/aU3eLZoV4Wi+7rO9gszn94xWSx/Pg/Jov23g5mi7aN XxkdeD0mNr9j91i85yWTx4NDm1k8Ni+p99h9s4HN4+PTWywe7/ddZfN4+3Inq8fnTXIBnFFc NimpOZllqUX6dglcGQtnvmQr6DatuHFwF0sD4yXtLkYODgkBE4kHt2W6GLk4hASWMknsWNrM AuHsYJTo3jGXqYuRE6xo9ft2JojEYkaJ9Uf6WEASwgJOEo9/fgUrEhGQlfi++zUbiC0kYCfx dv1OsEnMAntZJB5evsUKkmATMJL49n4mWDMvUFHD0y/sIDaLgKrEis9nwQaJCkRIbPo6B6pG UOLkzCcsIKdyCthLXD0QDmIyC2hKrN+lD1LBLCAvsf3tHGaQVRICE9gkPnReYIK4QV3i5JL5 TBMYhWchmTQLoX0WkvYFjMyrGMVyM3OKc9NTCwxN9YoT81Iyi7P1kvNzNzFCojFzB+PdJ96H GAU4GJV4eD9YsEUIsSaWFVfmHmKU4GBWEuGN6QUK8aYkVlalFuXHF5XmpBYfYpTmYFES53W7 9yVMSCA9sSQ1OzW1ILUIJsvEwSnVwBjHvuzO7q2LhWOC3hZzGO+6sN3CSU2/Wtf9/61TF+8/ O15fbm8t+dNhguTp4xcCXLsNOl+93iccknDf8/emPo1FHctn7tFJ/ZreIPZF7XUs5+rGPpP8 Llmvuztuzz3W//6bsOKPpNWHuW6/Kfpg+5wz94sm0zFxc7XvYr4h+lZRfFxnF8zY0KXEUpyR aKjFXFScCACuNBf0wgIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrOLMWRmVeSWpSXmKPExsXCtZGTTVdxJluEwakf1hb/9xxjs3h5/gOr xcrVR5ksVk3Ms7h39AuTxd5b2hbzlz1lt3h2qJfFovv6DjaL8x9eMVksP/6PyaK9t4PZom3j V0YHXo+Jze/YPRbvecnk8eDQZhaPzUvqPXbfbGDz+Pj0FovH+31X2TzevtzJ6vF5k1wAZxSX TUpqTmZZapG+XQJXxsKZL9kKuk0rbhzcxdLAeEm7i5GTQ0LARGL1+3amLkYuDiGBhYwSOxr3 s4MkhAWcJB7//MoEYosIyEp83/2aDcQWErCTeLt+JwtIA7PAXhaJjtunmEESbAJGEt/ez2QB sXmBihqefgEbxCKgKrHi81mwQaICERKbvs6BqhGUODnzCZDNwcEpYC9x9UA4SJhZQF3iz7xL zBC2vMT2t3OYJzDyzULSMQtJ2SwkZQsYmVcxiuVm5hTnpmcWGBrpFSfmpWQWZ+sl5+duYoRE RdQOxusTzQ8xMnFwSjUwmsR43YuQ6Jk436tRndP96wHLZP4V239F7w22efX6qkAfZ++bQsWF xsUHDjxkPGaydfdnj8nnpb9OZVkwc8mUPfot8zOalRvMluiFPls+m/FGwr5rp2bnrWKNFN0j NHuR7fElfzs/VGrZik6oX3lhd2z0PsfuHfyf/eI9i1QLhRUYzLf4Hn6kosRSnJFoqMVcVJwI AF7t8XE6AgAA X-EOPAttributedMessage: 0 X-MS-Office365-Filtering-HT: Tenant X-Forefront-Antispam-Report: CIP:63.163.107.21; 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This function does *not* wait until all outstanding requests have finished (this means invocation of request.end_io()). Signed-off-by: Bart Van Assche Cc: Ming Lei Cc: Hannes Reinecke Cc: Johannes Thumshirn --- block/blk-mq.c | 78 ++++++++++++++++++++++++++++++++++++++++++++------ include/linux/blk-mq.h | 3 ++ include/linux/blkdev.h | 1 + 3 files changed, 73 insertions(+), 9 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 4643fa8..d41ed92 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -115,6 +115,30 @@ void blk_mq_unfreeze_queue(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); +/** + * blk_mq_quiesce_queue() - wait until all ongoing queue_rq calls have finished + * + * Note: this function does not prevent that the struct request end_io() + * callback function is invoked. Additionally, it is not prevented that + * new queue_rq() calls occur unless the queue has been stopped first. + */ +void blk_mq_quiesce_queue(struct request_queue *q) +{ + struct blk_mq_hw_ctx *hctx; + unsigned int i; + bool rcu = false; + + queue_for_each_hw_ctx(q, hctx, i) { + if (hctx->flags & BLK_MQ_F_BLOCKING) + synchronize_srcu(&hctx->queue_rq_srcu); + else + rcu = true; + } + if (rcu) + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); + void blk_mq_wake_waiters(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; @@ -778,7 +802,7 @@ static inline unsigned int queued_to_index(unsigned int queued) * of IO. In particular, we'd like FIFO behaviour on handling existing * items on the hctx->dispatch list. Ignore that for now. */ -static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) +static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct request *rq; @@ -790,9 +814,6 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) if (unlikely(blk_mq_hctx_stopped(hctx))) return; - WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && - cpu_online(hctx->next_cpu)); - hctx->run++; /* @@ -883,6 +904,24 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) } } +static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) +{ + int srcu_idx; + + WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && + cpu_online(hctx->next_cpu)); + + if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { + rcu_read_lock(); + blk_mq_process_rq_list(hctx); + rcu_read_unlock(); + } else { + srcu_idx = srcu_read_lock(&hctx->queue_rq_srcu); + blk_mq_process_rq_list(hctx); + srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx); + } +} + /* * It'd be great if the workqueue API had a way to pass * in a mask and had some smarts for more clever placement. @@ -1278,6 +1317,14 @@ static int blk_mq_direct_issue_request(struct request *rq, blk_qc_t *cookie) return -1; } +static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + struct request *rq, blk_qc_t *cookie) +{ + if (blk_mq_hctx_stopped(hctx) || + blk_mq_direct_issue_request(rq, cookie) != 0) + blk_mq_insert_request(rq, false, true, true); +} + /* * Multiple hardware queue variant. This will not use per-process plugs, * but will attempt to bypass the hctx queueing if we can go straight to @@ -1289,7 +1336,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) const int is_flush_fua = bio->bi_opf & (REQ_PREFLUSH | REQ_FUA); struct blk_map_ctx data; struct request *rq; - unsigned int request_count = 0; + unsigned int request_count = 0, srcu_idx; struct blk_plug *plug; struct request *same_queue_rq = NULL; blk_qc_t cookie; @@ -1332,7 +1379,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_mq_bio_to_request(rq, bio); /* - * We do limited pluging. If the bio can be merged, do that. + * We do limited plugging. If the bio can be merged, do that. * Otherwise the existing request in the plug list will be * issued. So the plug list will have one request at most */ @@ -1352,9 +1399,16 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_mq_put_ctx(data.ctx); if (!old_rq) goto done; - if (blk_mq_hctx_stopped(data.hctx) || - blk_mq_direct_issue_request(old_rq, &cookie) != 0) - blk_mq_insert_request(old_rq, false, true, true); + + if (!(data.hctx->flags & BLK_MQ_F_BLOCKING)) { + rcu_read_lock(); + blk_mq_try_issue_directly(data.hctx, old_rq, &cookie); + rcu_read_unlock(); + } else { + srcu_idx = srcu_read_lock(&data.hctx->queue_rq_srcu); + blk_mq_try_issue_directly(data.hctx, old_rq, &cookie); + srcu_read_unlock(&data.hctx->queue_rq_srcu, srcu_idx); + } goto done; } @@ -1633,6 +1687,9 @@ static void blk_mq_exit_hctx(struct request_queue *q, if (set->ops->exit_hctx) set->ops->exit_hctx(hctx, hctx_idx); + if (hctx->flags & BLK_MQ_F_BLOCKING) + cleanup_srcu_struct(&hctx->queue_rq_srcu); + blk_mq_remove_cpuhp(hctx); blk_free_flush_queue(hctx->fq); sbitmap_free(&hctx->ctx_map); @@ -1713,6 +1770,9 @@ static int blk_mq_init_hctx(struct request_queue *q, flush_start_tag + hctx_idx, node)) goto free_fq; + if (hctx->flags & BLK_MQ_F_BLOCKING) + init_srcu_struct(&hctx->queue_rq_srcu); + return 0; free_fq: diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 523376a..02c3918 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -3,6 +3,7 @@ #include #include +#include struct blk_mq_tags; struct blk_flush_queue; @@ -35,6 +36,8 @@ struct blk_mq_hw_ctx { struct blk_mq_tags *tags; + struct srcu_struct queue_rq_srcu; + unsigned long queued; unsigned long run; #define BLK_MQ_MAX_DISPATCH_ORDER 7 diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index c47c358..8259d87 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -824,6 +824,7 @@ extern void __blk_run_queue(struct request_queue *q); extern void __blk_run_queue_uncond(struct request_queue *q); extern void blk_run_queue(struct request_queue *); extern void blk_run_queue_async(struct request_queue *q); +extern void blk_mq_quiesce_queue(struct request_queue *q); extern int blk_rq_map_user(struct request_queue *, struct request *, struct rq_map_data *, void __user *, unsigned long, gfp_t);