From patchwork Mon Apr 4 09:28:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suwan Kim X-Patchwork-Id: 12800045 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 DF314C433EF for ; Mon, 4 Apr 2022 09:28:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347122AbiDDJap (ORCPT ); Mon, 4 Apr 2022 05:30:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229984AbiDDJal (ORCPT ); Mon, 4 Apr 2022 05:30:41 -0400 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4047A22B2B for ; Mon, 4 Apr 2022 02:28:45 -0700 (PDT) Received: by mail-pl1-x62d.google.com with SMTP id p17so7628859plo.9 for ; Mon, 04 Apr 2022 02:28:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=O2dQ/xAFxjh1YaGRXT309dq1U3WwKPaBP+AWNXb/eVE=; b=iPRycRF66NFZ4zyadclcZ34dnUxQUGbFTv/oze9hDUlskLbmzPjB9EvZhjQNF9azxv mAmkQvgGTzIrVGL0sCdCaNS6GZXNp2PxDyyPJto7cgy4mmoHvlFmZ2bYe6QSp6aYRvJh GmbDIMcNf+DFqHx06ahvhe9XHsaO4B3ugMZuD08ayYOCOSqBMD7qb1BRI69tCRByUhAL d28kS7l2WoyWMP+GynJmbbYGu5sHSTCpmfQPrTSVIPMThC8au8m0DnmHDMe6cukMgM7r EmHxiqqA7/vhHBEro2zRy0q3vhtQsU/tY9Rc7RJfRZN6Okd66olwLM16+YQr18w/eKxC xy2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=O2dQ/xAFxjh1YaGRXT309dq1U3WwKPaBP+AWNXb/eVE=; b=nxq1cvTwKxNCt67gexyv+ssM3DfQPZZqo0bJqxeYyIPO9b8TH2nQ75nmm3U0zJh8eV 445191kyKjj6qBGSVE/npLcMZcOrbFgBI4VE1Mw1MFKtW4cSdELbGaxA9uXvu45MwJTp ESJeF4/i+NZ06FL7khlvflL5K/uE/9hnEVlRD2dgYcwTpGtElppEBhmjz5EUmN0Kbc1u tVoXIKh7UUirDRtzZbCLyVW4Gdqhk37B2P3K9riXkWJc+Y55nP4JB6QmrOWUWJnAhQrP O8xUPfOOQrBX+7EbYbvW7ercOr4W14+1sBn07s8eJ0owVPzIwn9ugHwNGxugPPGYcDSd C4bQ== X-Gm-Message-State: AOAM5326y5UuSMv7044vnfkwHoOaakQiF+1W9zazBMzMheh9mFY8fNLI p8ocizm/2vryBykPiTRzSPE= X-Google-Smtp-Source: ABdhPJzfNi/zp46Bh8LXol0dcZZ4Gw1PFeGe2hXHlDNumSiiaRuQh3MkPf/uKFzY4LXua2MxgvJVHA== X-Received: by 2002:a17:902:f68e:b0:154:6518:69ba with SMTP id l14-20020a170902f68e00b00154651869bamr22268306plg.60.1649064524698; Mon, 04 Apr 2022 02:28:44 -0700 (PDT) Received: from localhost.localdomain ([114.200.4.15]) by smtp.googlemail.com with ESMTPSA id x9-20020a17090a970900b001ca6c59b350sm6187675pjo.2.2022.04.04.02.28.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 02:28:43 -0700 (PDT) From: Suwan Kim To: mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, mgurtovoy@nvidia.com, dongli.zhang@oracle.com Cc: virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org, Suwan Kim Subject: [PATCH v4 2/2] virtio-blk: support mq_ops->queue_rqs() Date: Mon, 4 Apr 2022 18:28:05 +0900 Message-Id: <20220404092805.77643-3-suwan.kim027@gmail.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20220404092805.77643-1-suwan.kim027@gmail.com> References: <20220404092805.77643-1-suwan.kim027@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This patch supports mq_ops->queue_rqs() hook. It has an advantage of batch submission to virtio-blk driver. It also helps polling I/O because polling uses batched completion of block layer. Batch submission in queue_rqs() can boost polling performance. In queue_rqs(), it iterates plug->mq_list, collects requests that belong to same HW queue until it encounters a request from other HW queue or sees the end of the list. Then, virtio-blk adds requests into virtqueue and kicks virtqueue to submit requests. If there is an error, it inserts error request to requeue_list and passes it to ordinary block layer path. For verification, I did fio test. (io_uring, randread, direct=1, bs=4K, iodepth=64 numjobs=N) I set 4 vcpu and 2 virtio-blk queues for VM and run fio test 5 times. It shows about 2% improvement. | numjobs=2 | numjobs=4 ----------------------------------------------------------- fio without queue_rqs() | 291K IOPS | 238K IOPS ----------------------------------------------------------- fio with queue_rqs() | 295K IOPS | 243K IOPS For polling I/O performance, I also did fio test as below. (io_uring, hipri, randread, direct=1, bs=512, iodepth=64 numjobs=4) I set 4 vcpu and 2 poll queues for VM. It shows about 2% improvement in polling I/O. | IOPS | avg latency ----------------------------------------------------------- fio poll without queue_rqs() | 424K | 613.05 usec ----------------------------------------------------------- fio poll with queue_rqs() | 435K | 601.01 usec Signed-off-by: Suwan Kim --- drivers/block/virtio_blk.c | 110 +++++++++++++++++++++++++++++++++---- 1 file changed, 99 insertions(+), 11 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c2d955da0006..03e4455c23e3 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -92,6 +92,7 @@ struct virtio_blk { struct virtblk_req { struct virtio_blk_outhdr out_hdr; u8 status; + int sg_num; struct sg_table sg_table; struct scatterlist sg[]; }; @@ -311,18 +312,13 @@ static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx) virtqueue_notify(vq->vq); } -static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, - const struct blk_mq_queue_data *bd) +static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx, + struct virtio_blk *vblk, + struct request *req, + struct virtblk_req *vbr) { - struct virtio_blk *vblk = hctx->queue->queuedata; - struct request *req = bd->rq; - struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); - unsigned long flags; - int num; - int qid = hctx->queue_num; - bool notify = false; blk_status_t status; - int err; + int num; status = virtblk_setup_cmd(vblk->vdev, req, vbr); if (unlikely(status)) @@ -335,9 +331,30 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, virtblk_cleanup_cmd(req); return BLK_STS_RESOURCE; } + vbr->sg_num = num; + + return BLK_STS_OK; +} + +static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct virtio_blk *vblk = hctx->queue->queuedata; + struct request *req = bd->rq; + struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + unsigned long flags; + int qid = hctx->queue_num; + bool notify = false; + blk_status_t status; + int err; + + status = virtblk_prep_rq(hctx, vblk, req, vbr); + if (unlikely(status)) + return status; spin_lock_irqsave(&vblk->vqs[qid].lock, flags); - err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg_table.sgl, num); + err = virtblk_add_req(vblk->vqs[qid].vq, vbr, + vbr->sg_table.sgl, vbr->sg_num); if (err) { virtqueue_kick(vblk->vqs[qid].vq); /* Don't stop the queue if -ENOMEM: we may have failed to @@ -367,6 +384,76 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, return BLK_STS_OK; } +static bool virtblk_prep_rq_batch(struct request *req) +{ + struct virtio_blk *vblk = req->mq_hctx->queue->queuedata; + struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + + req->mq_hctx->tags->rqs[req->tag] = req; + + return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK; +} + +static bool virtblk_add_req_batch(struct virtio_blk_vq *vq, + struct request **rqlist, + struct request **requeue_list) +{ + unsigned long flags; + int err; + bool kick; + + spin_lock_irqsave(&vq->lock, flags); + + while (!rq_list_empty(*rqlist)) { + struct request *req = rq_list_pop(rqlist); + struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + + err = virtblk_add_req(vq->vq, vbr, + vbr->sg_table.sgl, vbr->sg_num); + if (err) { + virtblk_unmap_data(req, vbr); + virtblk_cleanup_cmd(req); + rq_list_add(requeue_list, req); + } + } + + kick = virtqueue_kick_prepare(vq->vq); + spin_unlock_irqrestore(&vq->lock, flags); + + return kick; +} + +static void virtio_queue_rqs(struct request **rqlist) +{ + struct request *req, *next, *prev = NULL; + struct request *requeue_list = NULL; + + rq_list_for_each_safe(rqlist, req, next) { + struct virtio_blk_vq *vq = req->mq_hctx->driver_data; + bool kick; + + if (!virtblk_prep_rq_batch(req)) { + rq_list_move(rqlist, &requeue_list, req, prev); + req = prev; + if (!req) + continue; + } + + if (!next || req->mq_hctx != next->mq_hctx) { + req->rq_next = NULL; + kick = virtblk_add_req_batch(vq, rqlist, &requeue_list); + if (kick) + virtqueue_notify(vq->vq); + + *rqlist = next; + prev = NULL; + } else + prev = req; + } + + *rqlist = requeue_list; +} + /* return id (s/n) string for *disk to *id_str */ static int virtblk_get_id(struct gendisk *disk, char *id_str) @@ -834,6 +921,7 @@ static int virtblk_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, static const struct blk_mq_ops virtio_mq_ops = { .queue_rq = virtio_queue_rq, + .queue_rqs = virtio_queue_rqs, .commit_rqs = virtio_commit_rqs, .init_hctx = virtblk_init_hctx, .complete = virtblk_request_done,