From patchwork Sat Nov 27 10:11:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12642183 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 2F0B7C433EF for ; Sat, 27 Nov 2021 10:01:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353897AbhK0KEh (ORCPT ); Sat, 27 Nov 2021 05:04:37 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:27305 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353889AbhK0KCh (ORCPT ); Sat, 27 Nov 2021 05:02:37 -0500 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4J1Rsd2703zbj7m; Sat, 27 Nov 2021 17:59:17 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Sat, 27 Nov 2021 17:59:21 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Sat, 27 Nov 2021 17:59:20 +0800 From: Yu Kuai To: , , CC: , , , , Subject: [PATCH RFC 0/9] support concurrent sync io for bfq on a specail occasion Date: Sat, 27 Nov 2021 18:11:23 +0800 Message-ID: <20211127101132.486806-1-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Bfq can't handle sync io concurrently as long as the io are not issued from root group currently. Previous patch set: https://lore.kernel.org/lkml/20211014014556.3597008-2-yukuai3@huawei.com/t/ During implemting the method mentioned by the above patch set, I found more problems that will block implemting concurrent sync io. The modifications of this patch set are as follows: 1) count root group into 'num_groups_with_pending_reqs'; 2) don't idle if 'num_groups_with_pending_reqs' is 1; 3) If the group doesn't have pending requests while it's child groups have pending requests, don't count the group. 4) Once the group doesn't have pending requests, decrease 'num_groups_with_pending_reqs' immediately. Don't delay to when all it's child groups don't have pending requests. Noted that I just tested basic functionality of this patchset, and I think it's better to see if anyone have suggestions or better solutions. Yu Kuai (9): block, bfq: add new apis to iterate bfq entities block, bfq: apply news apis where root group is not expected block, bfq: handle the case when for_each_entity() access root group block, bfq: count root group into 'num_groups_with_pending_reqs' block, bfq: do not idle if only one cgroup is activated block, bfq: only count group that the bfq_queue belongs to block, bfq: record how many queues have pending requests in bfq_group block, bfq: move forward __bfq_weights_tree_remove() block, bfq: decrease 'num_groups_with_pending_reqs' earlier block/bfq-cgroup.c | 3 +- block/bfq-iosched.c | 92 +++++++++++++++++++++++---------------------- block/bfq-iosched.h | 41 +++++++++++++------- block/bfq-wf2q.c | 44 +++++++++++++++------- 4 files changed, 106 insertions(+), 74 deletions(-)