From patchwork Sat Mar 5 09:12:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12770289 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 E85A7C433FE for ; Sat, 5 Mar 2022 08:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231133AbiCEI5i (ORCPT ); Sat, 5 Mar 2022 03:57:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230468AbiCEI5h (ORCPT ); Sat, 5 Mar 2022 03:57:37 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02A44254AA0; Sat, 5 Mar 2022 00:56:46 -0800 (PST) Received: from kwepemi500023.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4K9dkm6vXQzbc6y; Sat, 5 Mar 2022 16:52:00 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi500023.china.huawei.com (7.221.188.76) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.18; Sat, 5 Mar 2022 16:56:44 +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 15.1.2308.21; Sat, 5 Mar 2022 16:56:43 +0800 From: Yu Kuai To: , , , CC: , , , , Subject: [PATCH -next 06/11] block, bfq: do not idle if only one cgroup is activated Date: Sat, 5 Mar 2022 17:12:00 +0800 Message-ID: <20220305091205.4188398-7-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220305091205.4188398-1-yukuai3@huawei.com> References: <20220305091205.4188398-1-yukuai3@huawei.com> 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 Now that root group is counted into 'num_groups_with_pending_reqs', 'num_groups_with_pending_reqs > 0' is always true in bfq_asymmetric_scenario(). Thus change the condition to 'num_groups_with_pending_reqs > 1', so it's consistent without counting root group. On the other hand, with the following patches to only count groups(not ancestors) with pending requests, sync io can be handled concurrently if only one group has pending requests. Signed-off-by: Yu Kuai --- block/bfq-iosched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 3bc7a7686aad..07027dc9dc4c 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -812,7 +812,7 @@ bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) * much easier to maintain the needed state: * 1) all active queues have the same weight, * 2) all active queues belong to the same I/O-priority class, - * 3) there are no active groups. + * 3) there are one active groups at most. * In particular, the last condition is always true if hierarchical * support or the cgroups interface are not enabled, thus no state * needs to be maintained in this case. @@ -844,7 +844,7 @@ static bool bfq_asymmetric_scenario(struct bfq_data *bfqd, return varied_queue_weights || multiple_classes_busy #ifdef CONFIG_BFQ_GROUP_IOSCHED - || bfqd->num_groups_with_pending_reqs > 0 + || bfqd->num_groups_with_pending_reqs > 1 #endif ; }