From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CBF2C6786E for ; Fri, 26 Oct 2018 08:05:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5BED2082E for ; Fri, 26 Oct 2018 08:05:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Tngvpnkq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5BED2082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726852AbeJZQlG (ORCPT ); Fri, 26 Oct 2018 12:41:06 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:57540 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725907AbeJZQlG (ORCPT ); Fri, 26 Oct 2018 12:41:06 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9Q7wuP9191767; Fri, 26 Oct 2018 08:04:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=D5Yagcn33sTdWaG+JcjoP6IuMFXU6NPHli2REDhzIfQ=; b=TngvpnkqgYmfHFvyHJblUQIHWuNUXM1B5TiRQ/o1UfPWmJxf9I807VkqefDUbEhE8ViN c5ya74zpEHGsTB24pURstcLgWetyjA8BivRxz5ytCYcxlC+bExS06CHNBOXBay0x5nWj efVkhkYOLT/iPXAR+/iMC55bPtm84XqvMT2vAllN49jY392jcqx4XgoDDWDZziwI6+zd AvsNNCuDnvU2TB+Trp83oCr9nQFb8QTIaxZR480XzdM+SMmNUO1eqRCwkNRxB7Stl7uk fL5OCdPKCz/vodDIz7zZPcY8k29l3E6EGHozRtuq0BRiQQBU39b5zwjGDt8eOOeUQKhu qg== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by aserp2120.oracle.com with ESMTP id 2n7vaqdrqc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 26 Oct 2018 08:04:58 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9Q84vdb006801 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 26 Oct 2018 08:04:58 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w9Q84vW5028434; Fri, 26 Oct 2018 08:04:57 GMT Received: from [10.182.70.180] (/10.182.70.180) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 26 Oct 2018 01:04:56 -0700 Subject: Re: [PATCH V3] block: fix the DISCARD request merge To: axboe@kernel.dk Cc: martin.petersen@oracle.com, Ming Lei , hch@lst.de, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <1540350450-15208-1-git-send-email-jianchao.w.wang@oracle.com> From: "jianchao.wang" Message-ID: <52d2e36c-ed62-151d-e070-7edd06bfc24d@oracle.com> Date: Fri, 26 Oct 2018 16:05:00 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1540350450-15208-1-git-send-email-jianchao.w.wang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9057 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810260072 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Would anyone please take a look at this ? Thanks in advance. Jianchao On 10/24/18 11:07 AM, Jianchao Wang wrote: > There are two cases when handle DISCARD merge. > If max_discard_segments == 1, the bios/requests need to be contiguous > to merge. If max_discard_segments > 1, it takes every bio as a range > and different range needn't to be contiguous. > > But now, attempt_merge screws this up. It always consider contiguity > for DISCARD for the case max_discard_segments > 1 and cannot merge > contiguous DISCARD for the case max_discard_segments == 1, because > rq_attempt_discard_merge always returns false in this case. > This patch fixes both of the two cases above. > > Signed-off-by: Jianchao Wang > --- > > V3: > - Introduce blk_discard_mergable into attempt_merge and > blk_try_merge. > - Some comment changes. > > V2: > - Add max_discard_segments > 1 checking in attempt_merge. > - Change patch title and comment. > - Add more comment in attempt_merge > > block/blk-merge.c | 34 ++++++++++++++++++++++++---------- > 1 file changed, 24 insertions(+), 10 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 42a4674..b258de0 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -714,6 +714,22 @@ static void blk_account_io_merge(struct request *req) > part_stat_unlock(); > } > } > +/* > + * Two cases of handling DISCARD merge: > + * If max_discard_segments > 1, the driver takes every bio > + * as a range and send them to controller together. The ranges > + * needn't to be contiguous. > + * Otherwise, the bios/requests will be handled as same as > + * others which should be contiguous. > + */ > +static inline bool blk_discard_mergable(struct request *req) > +{ > + if (req_op(req) == REQ_OP_DISCARD && > + queue_max_discard_segments(req->q) > 1) > + return true; > + else > + return false; > +} > > /* > * For non-mq, this has to be called with the request spinlock acquired. > @@ -731,12 +747,6 @@ static struct request *attempt_merge(struct request_queue *q, > if (req_op(req) != req_op(next)) > return NULL; > > - /* > - * not contiguous > - */ > - if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) > - return NULL; > - > if (rq_data_dir(req) != rq_data_dir(next) > || req->rq_disk != next->rq_disk > || req_no_special_merge(next)) > @@ -760,11 +770,16 @@ static struct request *attempt_merge(struct request_queue *q, > * counts here. Handle DISCARDs separately, as they > * have separate settings. > */ > - if (req_op(req) == REQ_OP_DISCARD) { > + > + if (blk_discard_mergable(req)) { > if (!req_attempt_discard_merge(q, req, next)) > return NULL; > - } else if (!ll_merge_requests_fn(q, req, next)) > + } else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) { > + if (!ll_merge_requests_fn(q, req, next)) > + return NULL; > + } else { > return NULL; > + } > > /* > * If failfast settings disagree or any of the two is already > @@ -888,8 +903,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) > > enum elv_merge blk_try_merge(struct request *rq, struct bio *bio) > { > - if (req_op(rq) == REQ_OP_DISCARD && > - queue_max_discard_segments(rq->q) > 1) > + if (blk_discard_mergable(rq)) > return ELEVATOR_DISCARD_MERGE; > else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) > return ELEVATOR_BACK_MERGE; >