From patchwork Wed Aug 8 09:56:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "jianchao.wang" X-Patchwork-Id: 10559705 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 9FB2314E5 for ; Wed, 8 Aug 2018 09:55:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8AB0528E65 for ; Wed, 8 Aug 2018 09:55:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7EC602AA63; Wed, 8 Aug 2018 09:55:31 +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 F3C7128E65 for ; Wed, 8 Aug 2018 09:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726643AbeHHMO0 (ORCPT ); Wed, 8 Aug 2018 08:14:26 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:46906 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726542AbeHHMO0 (ORCPT ); Wed, 8 Aug 2018 08:14:26 -0400 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 w789raoM119490; Wed, 8 Aug 2018 09:55:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2018-07-02; bh=aq6laXVyJOvqQ7y3+nnHuM9B0K/O0GRCDQg9jaFPd/c=; b=IKmDemuZ1APZmV1brx72dRS1gQTSb06m3arXEaIbx6zeXf32dfwl+mA+jpVEeMIiksNy DNSDkmLEgs4gB8UNtrGWPpLMbsh45ZkO2ApFgtGa29aXnHLupW9fjEvvbHG87lwkVYuy AsP9thsBTEPGJ9i7/qWSP+RqIfoMXqCUo3Nddu4QV6ho3v3JP+FVWtZcbpZdNyCXZIrh zaNKQG2CzKvOECxM30VFk9hnSizjy/+ygCKnbcd3eEws44ZXxLSwWDacF+hLxliimh0x we+JLcBUdMEBX5+bcd6ABIA8w3FQIw01/RhAENke7fGzfuhXdJWnnurlRoysGpGA3IJy tw== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2kn4spw1pn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 08 Aug 2018 09:55:26 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w789tPaJ023846 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 8 Aug 2018 09:55:25 GMT Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w789tMHS010656; Wed, 8 Aug 2018 09:55:25 GMT Received: from will-ThinkCentre-M910s.cn.oracle.com (/10.182.70.254) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 08 Aug 2018 02:55:21 -0700 From: Jianchao Wang To: axboe@kernel.dk Cc: tom.leiming@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2] blk-mq: count the hctx as active before allocate tag Date: Wed, 8 Aug 2018 17:56:52 +0800 Message-Id: <1533722212-20327-1-git-send-email-jianchao.w.wang@oracle.com> X-Mailer: git-send-email 2.7.4 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8978 signatures=668707 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=978 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808080101 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 Currently, we count the hctx as active after allocate driver tag successfully. The other shared-tags users could exhaust the driver tags and starve a non-active and waiting-tag hctx. Count the hctx as active before try to allocate driver tag to fix this. Signed-off-by: Jianchao Wang --- V2: only invoke blk_mq_tag_busy w/o io scheduler in blk_mq_get_request block/blk-mq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index ae44e85..75ac3fbd 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -285,7 +285,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, rq->tag = -1; rq->internal_tag = tag; } else { - if (blk_mq_tag_busy(data->hctx)) { + if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) { rq_flags = RQF_MQ_INFLIGHT; atomic_inc(&data->hctx->nr_active); } @@ -367,6 +367,8 @@ static struct request *blk_mq_get_request(struct request_queue *q, if (!op_is_flush(op) && e->type->ops.mq.limit_depth && !(data->flags & BLK_MQ_REQ_RESERVED)) e->type->ops.mq.limit_depth(op, data); + } else { + blk_mq_tag_busy(data->hctx); } tag = blk_mq_get_tag(data); @@ -972,6 +974,7 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, .hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), .flags = wait ? 0 : BLK_MQ_REQ_NOWAIT, }; + bool shared; might_sleep_if(wait); @@ -981,9 +984,10 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) data.flags |= BLK_MQ_REQ_RESERVED; + shared = blk_mq_tag_busy(data.hctx); rq->tag = blk_mq_get_tag(&data); if (rq->tag >= 0) { - if (blk_mq_tag_busy(data.hctx)) { + if (shared) { rq->rq_flags |= RQF_MQ_INFLIGHT; atomic_inc(&data.hctx->nr_active); }