From patchwork Mon Mar 21 14:24:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suwan Kim X-Patchwork-Id: 12787317 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 C5D7CC433EF for ; Mon, 21 Mar 2022 14:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349090AbiCUOaU (ORCPT ); Mon, 21 Mar 2022 10:30:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349440AbiCUO37 (ORCPT ); Mon, 21 Mar 2022 10:29:59 -0400 Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4331557B21 for ; Mon, 21 Mar 2022 07:25:23 -0700 (PDT) Received: by mail-pg1-x532.google.com with SMTP id c2so10408719pga.10 for ; Mon, 21 Mar 2022 07:25:23 -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=eJN4rSp81QMOseaNx/QepgZxezZlQQt9vNJia9NxfV8=; b=bSJzjq0aWHwQaZYRhu1aUexYauucvAGyjx7hphnX/Q5q08EKukctJbx9VvreqDCXdL mEpPfyl63qwmlxXVTE81jUuqDOq7nSyR/kqIH8TxvWOACy5ji50cHdgZlhwatKBkFyPp 5uvvqWRPzC18o/2Mq3D4iJySLmGaDfHmPO+Kn9A34vCy+KsL8GL5WEnWxuqSlxZoXg4G h2unW6KOuUbDFg9kXiOJcR6rydJ0X3Q3UagbrNT0rr1bCl5C7f8iBu5Miigs0/nSTvDB O5q54Aeni6IK1ePYZ0nKzSmdS1WRwjfL2jjbV95/p/uvq7D20BTQ2mNB1Qf2EMg8LhdG Digg== 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=eJN4rSp81QMOseaNx/QepgZxezZlQQt9vNJia9NxfV8=; b=Kr1kmy2B7GVevVCibyAPlgVTVGydoqmGs8cm8qWBFEypiax610TadfU15yERhiCTCO k1at8+lsqYvoU+Ni4gQcXJFG3mwDscAZI/hYrkzmzLeOOy/ZXOp2gpF7Sj4nhjoB4WPm k9Rybho0Jks0Dvr2pWNfNcApO/QqPvianH2X3xbkGUjSUxvLgREyLXqMkW+cNtU+9mb7 vjMlwYfrUN5g3+N7SidWdCkulH6fGxMHdbRagQdgCwJ1ajN5Tp8ThnP+8o7qPYGOXCvC G7GZrg/D7KaXaHJnfciTn64jKN79BfkEKi/88lL3DDJK10qvUnUErFkjbSdOXN2k3vIh awLg== X-Gm-Message-State: AOAM533s25va4Wp8JZWtOkLzgyiClXZxoevpiHS2coWsXSZEerpOpp76 +Ey0aHmB4wyv9XlNQ1pc8aM= X-Google-Smtp-Source: ABdhPJwu0JLsXJ+KGdPnDlowHZOZ3+qycFQyLZI04J+WMhIze12/zRgCsoGWb62gnPn/3NV83UTqHg== X-Received: by 2002:a63:520c:0:b0:382:2953:a338 with SMTP id g12-20020a63520c000000b003822953a338mr13315871pgb.610.1647872722766; Mon, 21 Mar 2022 07:25:22 -0700 (PDT) Received: from localhost.localdomain ([114.200.4.15]) by smtp.googlemail.com with ESMTPSA id e6-20020a056a001a8600b004f78e446ff5sm20503225pfv.15.2022.03.21.07.25.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Mar 2022 07:25:22 -0700 (PDT) From: Suwan Kim To: mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, mgurtovoy@nvidia.com Cc: virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org, Suwan Kim Subject: [PATCH v2 2/2] virtio-blk: support mq_ops->queue_rqs() Date: Mon, 21 Mar 2022 23:24:41 +0900 Message-Id: <20220321142441.132888-3-suwan.kim027@gmail.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20220321142441.132888-1-suwan.kim027@gmail.com> References: <20220321142441.132888-1-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 and adds requests into virtqueue until it encounters a request from other HW queue or sees the end of the list. Then, virtio-blk 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 1-4% improvement. | numjobs=2 | numjobs=4 ----------------------------------------------------------- fio without queue_rqs() | 282K IOPS | 245K IOPS ----------------------------------------------------------- fio with queue_rqs() | 294K IOPS | 249K 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 upto 7% improvement in polling I/O. | IOPS | avg latency ----------------------------------------------------------- fio poll without queue_rqs() | 413K | 619.72us ----------------------------------------------------------- fio poll with queue_rqs() | 445K | 581.2 usec Signed-off-by: Suwan Kim --- drivers/block/virtio_blk.c | 93 ++++++++++++++++++++++++++++++++++---- 1 file changed, 84 insertions(+), 9 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index cd3e11bb8559..b129d9b277ce 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -311,6 +311,28 @@ static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx) virtqueue_notify(vq->vq); } +static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx, + struct virtio_blk *vblk, + struct request *req, + struct virtblk_req *vbr, int *num) +{ + blk_status_t status; + + status = virtblk_setup_cmd(vblk->vdev, req, vbr); + if (unlikely(status)) + return status; + + blk_mq_start_request(req); + + *num = virtblk_map_data(hctx, req, vbr); + if (unlikely(*num < 0)) { + virtblk_cleanup_cmd(req); + return BLK_STS_RESOURCE; + } + + return BLK_STS_OK; +} + static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { @@ -324,18 +346,10 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, blk_status_t status; int err; - status = virtblk_setup_cmd(vblk->vdev, req, vbr); + status = virtblk_prep_rq(hctx, vblk, req, vbr, &num); if (unlikely(status)) return status; - blk_mq_start_request(req); - - num = virtblk_map_data(hctx, req, vbr); - if (unlikely(num < 0)) { - virtblk_cleanup_cmd(req); - return BLK_STS_RESOURCE; - } - spin_lock_irqsave(&vblk->vqs[qid].lock, flags); err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg_table.sgl, num); if (err) { @@ -367,6 +381,66 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, return BLK_STS_OK; } +static bool virtblk_prep_rq_batch(struct virtio_blk_vq *vq, struct request *req) +{ + struct virtio_blk *vblk = req->mq_hctx->queue->queuedata; + struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + unsigned long flags; + int num, err; + + req->mq_hctx->tags->rqs[req->tag] = req; + + if (virtblk_prep_rq(req->mq_hctx, vblk, req, vbr, &num) != BLK_STS_OK) + return false; + + spin_lock_irqsave(&vq->lock, flags); + err = virtblk_add_req(vq->vq, vbr, vbr->sg_table.sgl, num); + if (err) { + spin_unlock_irqrestore(&vq->lock, flags); + virtblk_unmap_data(req, vbr); + virtblk_cleanup_cmd(req); + return false; + } + spin_unlock_irqrestore(&vq->lock, flags); + + return true; +} + +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; + unsigned long flags; + bool kick; + + if (!virtblk_prep_rq_batch(vq, req)) { + rq_list_move(rqlist, &requeue_list, req, prev); + req = prev; + + if (!req) + continue; + } + + if (!next || req->mq_hctx != next->mq_hctx) { + spin_lock_irqsave(&vq->lock, flags); + kick = virtqueue_kick_prepare(vq->vq); + spin_unlock_irqrestore(&vq->lock, flags); + if (kick) + virtqueue_notify(vq->vq); + + req->rq_next = NULL; + *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) @@ -823,6 +897,7 @@ 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,