From patchwork Tue Apr 5 05:31:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suwan Kim X-Patchwork-Id: 12801031 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 A7423C433EF for ; Tue, 5 Apr 2022 05:32:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229873AbiDEFd5 (ORCPT ); Tue, 5 Apr 2022 01:33:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229754AbiDEFd4 (ORCPT ); Tue, 5 Apr 2022 01:33:56 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45BD3CF5 for ; Mon, 4 Apr 2022 22:31:59 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id b130so10116207pga.13 for ; Mon, 04 Apr 2022 22:31:59 -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=aXRz0EkWJNGUKj9FcrT3RlKSXvjHH2nO+rpSazhP1Rw=; b=hTVYU4NAR4dRjdqTT7IcHOz0enI391NAJQeeVCvSiWZ2njw2Ag2+aakmlSKSBGLEbf Nd247tKwVv4nb5MB4Mwexya2p0EIZVwO+fRISVWqTOywLpEA+jgg3NfPdfkX16rYsia1 H+GLid8i8fH1zcVCQRevIjkr/ot04HSwJoyd7uANouZW9kbdc9IQhohCIktGR2/qcSDl AVV+y5ZvvbJpHddzZU2b2PNOsPIoVf8dZlOzZBIgdX5zUlZhSeuu0mvrco3xCEJ+iP2C ia1bfGz/6+fpXPtq52LqEMlmuSnrcVeEFojQiUacLEOFTd9NUcIcFtmO35disCpLf4ZT fiYg== 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=aXRz0EkWJNGUKj9FcrT3RlKSXvjHH2nO+rpSazhP1Rw=; b=3DzxC0KcP6gAF85H2h5cRqBj7xKgnTrB4OxcmqWrP3Wzi/bUotCq5nC1sAQBJ4cBbA R5asZd4o4ZljpIa1XyHCW5C8b+Qfqnqj2woy7Dy+h/Af7kN1E/irOPMh4grSYOT+0ZlC 6dj9jhpsxiHfKpoUQtRFCxIlduYf2AGhBPVb+U4KdzARyB2erUH1HoirWNMZMRQxxQLj TS+903YFT5khqhuEwV0n5rxaWjYN/c2qkrPOlb79j1Cnwol8r4uF6YCT7iRCEKMzfOg+ QGI20TnXbz+ZO41S4S82Ceo78NF9qvvb3Tn8daIu8cP07RKV2C4xuLJqlcJCC9dThSXO fhBQ== X-Gm-Message-State: AOAM530AneXIexH3licn/gPolJ6eTzW9Y78QZW26X70d1RI0TWpn1uRC yJVmMGy51QhcLuu/4zA+TMk= X-Google-Smtp-Source: ABdhPJxtffzcZpmViA/40aCJPeOBkeyZWzUJLgi50xs6D7vZiy7wX9fLxcXO0zNRtkMU0kFQASjCyg== X-Received: by 2002:a63:5b48:0:b0:381:10:43e5 with SMTP id l8-20020a635b48000000b00381001043e5mr1477982pgm.544.1649136718743; Mon, 04 Apr 2022 22:31:58 -0700 (PDT) Received: from localhost.localdomain ([114.200.4.15]) by smtp.googlemail.com with ESMTPSA id g1-20020a17090adac100b001c67cedd84esm866141pjx.42.2022.04.04.22.31.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 22:31:58 -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: Tue, 5 Apr 2022 14:31:22 +0900 Message-Id: <20220405053122.77626-3-suwan.kim027@gmail.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20220405053122.77626-1-suwan.kim027@gmail.com> References: <20220405053122.77626-1-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 Reviewed-by: Stefan Hajnoczi --- 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 712579dcd3cc..a091034bc551 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,