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=-12.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 2B50CC4320E for ; Tue, 17 Aug 2021 07:02:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 106FE6054F for ; Tue, 17 Aug 2021 07:02:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238083AbhHQHDB (ORCPT ); Tue, 17 Aug 2021 03:03:01 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3653 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234284AbhHQHDA (ORCPT ); Tue, 17 Aug 2021 03:03:00 -0400 Received: from fraeml713-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Gphlc1rRfz6FH0J; Tue, 17 Aug 2021 15:01:32 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml713-chm.china.huawei.com (10.206.15.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 17 Aug 2021 09:02:25 +0200 Received: from [10.47.93.112] (10.47.93.112) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 17 Aug 2021 08:02:24 +0100 Subject: Re: [PATCH v2 00/11] blk-mq: Reduce static requests memory footprint for shared sbitmap To: , , CC: , , , , , References: <1628519378-211232-1-git-send-email-john.garry@huawei.com> From: John Garry Message-ID: <2bb17ba5-2c7e-f1e3-6369-541369efd6b6@huawei.com> Date: Tue, 17 Aug 2021 08:02:11 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <1628519378-211232-1-git-send-email-john.garry@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.93.112] X-ClientProxiedBy: lhreml728-chm.china.huawei.com (10.201.108.79) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/08/2021 15:29, John Garry wrote: Hi guys, Any chance to review or test this? Thanks! > Currently a full set of static requests are allocated per hw queue per > tagset when shared sbitmap is used. > > However, only tagset->queue_depth number of requests may be active at > any given time. As such, only tagset->queue_depth number of static > requests are required. > > The same goes for using an IO scheduler, which allocates a full set of > static requests per hw queue per request queue. > > This series changes shared sbitmap support by using a shared tags per > tagset and request queue. Ming suggested something along those lines in > v1. But we'll keep name "shared sbitmap" name as it is fimilar. In using > a shared tags, the static rqs also become shared, reducing the number of > sets of static rqs, reducing memory usage. > > Patch "blk-mq: Use shared tags for shared sbitmap support" is a bit big, > and could be broken down. But then maintaining ability to bisect > becomes harder and each sub-patch would get more convoluted. > > For megaraid sas driver on my 128-CPU arm64 system with 1x SATA disk, we > save approx. 300MB(!) [370MB -> 60MB] > > Baseline is 2112f5c1330a (for-5.15/block) loop: Select I/O scheduler ... > > Changes since v1: > - Switch to use blk_mq_tags for shared sbitmap > - Add new blk_mq_ops init request callback > - Add some RB tags (thanks!) > > John Garry (11): > blk-mq: Change rqs check in blk_mq_free_rqs() > block: Rename BLKDEV_MAX_RQ -> BLKDEV_DEFAULT_RQ > blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests() > blk-mq: Invert check in blk_mq_update_nr_requests() > blk-mq-sched: Rename blk_mq_sched_alloc_{tags -> map_and_request}() > blk-mq: Pass driver tags to blk_mq_clear_rq_mapping() > blk-mq: Add blk_mq_tag_update_sched_shared_sbitmap() > blk-mq: Add blk_mq_ops.init_request_no_hctx() > scsi: Set blk_mq_ops.init_request_no_hctx > blk-mq: Use shared tags for shared sbitmap support > blk-mq: Stop using pointers for blk_mq_tags bitmap tags > > block/bfq-iosched.c | 4 +- > block/blk-core.c | 2 +- > block/blk-mq-debugfs.c | 8 +-- > block/blk-mq-sched.c | 92 +++++++++++++------------ > block/blk-mq-sched.h | 2 +- > block/blk-mq-tag.c | 111 +++++++++++++----------------- > block/blk-mq-tag.h | 12 ++-- > block/blk-mq.c | 144 +++++++++++++++++++++++---------------- > block/blk-mq.h | 8 +-- > block/kyber-iosched.c | 4 +- > block/mq-deadline-main.c | 2 +- > drivers/block/rbd.c | 2 +- > drivers/scsi/scsi_lib.c | 6 +- > include/linux/blk-mq.h | 20 +++--- > include/linux/blkdev.h | 5 +- > 15 files changed, 218 insertions(+), 204 deletions(-) >