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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EFA4C433EF for ; Wed, 20 Oct 2021 11:53:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EABB6610FF for ; Wed, 20 Oct 2021 11:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230092AbhJTL4H (ORCPT ); Wed, 20 Oct 2021 07:56:07 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:13958 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbhJTL4G (ORCPT ); Wed, 20 Oct 2021 07:56:06 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HZ89H2ttlzZcLW; Wed, 20 Oct 2021 19:52:03 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.15; Wed, 20 Oct 2021 19:53:50 +0800 Received: from [10.174.176.73] (10.174.176.73) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.15; Wed, 20 Oct 2021 19:53:49 +0800 Subject: Re: [PATCH v4 1/2] block, bfq: counted root group into 'num_groups_with_pending_reqs' To: Paolo Valente CC: Jens Axboe , linux-block , , References: <20211014014556.3597008-1-yukuai3@huawei.com> <20211014014556.3597008-2-yukuai3@huawei.com> <0DD9CFF0-6110-497D-A352-9F37CADADC6B@linaro.org> <1f89cece-a123-6190-bb72-d59035dac266@huawei.com> <2E8712BB-5BFB-4647-AE9A-B06E199500D7@linaro.org> <8912e5ca-67bb-4a9a-a2ce-ba13e0fc86ed@huawei.com> From: "yukuai (C)" Message-ID: Date: Wed, 20 Oct 2021 19:53:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2021/10/20 17:43, Paolo Valente wrote: > > >> Il giorno 20 ott 2021, alle ore 11:38, yukuai (C) ha scritto: >> >> On 2021/10/20 17:29, Paolo Valente wrote: >>>> Il giorno 20 ott 2021, alle ore 11:20, yukuai (C) ha scritto: >>>> >>>> On 2021/10/20 16:51, Paolo Valente wrote: >>>> >>>>>> @@ -860,9 +870,25 @@ void bfq_weights_tree_remove(struct bfq_data *bfqd, >>>>>> struct bfq_queue *bfqq) >>>>>> { >>>>>> struct bfq_entity *entity = bfqq->entity.parent; >>>>>> + struct bfq_sched_data *sd; >>>>>> + >>>>>> + /* >>>>>> + * If the bfq queue is in root group, the decrement of >>>>>> + * num_groups_with_pending_reqs is performed immediately upon the >>>>>> + * deactivation of entity. >>>>>> + */ >>>>>> + if (!entity) { >>>>>> + entity = &bfqd->root_group->entity; >>>>>> + sd = entity->my_sched_data; >>>>>> + >>>>>> + if (!sd->in_service_entity) >>>>>> + bfq_clear_group_with_pending_reqs(bfqd, entity); >>>>>> + >>>>>> + return; >>>>>> + } >>>>>> >>>>>> for_each_entity(entity) { >>>>>> - struct bfq_sched_data *sd = entity->my_sched_data; >>>>>> + sd = entity->my_sched_data; >>>>>> >>>>>> if (sd->next_in_service || sd->in_service_entity) { >>>>>> /* >>>>>> @@ -880,7 +906,8 @@ void bfq_weights_tree_remove(struct bfq_data *bfqd, >>>>>> } >>>>>> >>>>>> /* >>>>>> - * The decrement of num_groups_with_pending_reqs is >>>>>> + * If the bfq queue is not in root group, >>>>>> + * the decrement of num_groups_with_pending_reqs is >>>>> I'm sorry if I didn't notice this before, but why do you postpone the >>>>> decrement only for queues not in root group? If I'm not missing >>>>> anything, the active (i.e., with pending reqs) state of the root group >>>>> is to be computed as that of ay other group. >>>> >>>> Hi, Paolo >>>> >>>> I thought if queue is in root group, then bfqq->entity.parent is NULL, >>>> and such case is handled above, which is separate from previous >>>> implementation for queues that are not in root group. >>>> >>>> Is this the wrong way to handle root group? >>>> >>> I think that, if we want to count also the root group among the active >>> ones, then the logic for tagging the root group as active must be the >>> same as the other groups. Or am I missing something? >> >> Hi, Paolo >> >> Currently, if queue is in root group, bfqq->entity.parent is NULL, and >> this makes it hard to keep the same logic. >> >> Can we store root_group->my_entity to bfqq->entity.parent if the queue >> is in root group? >> > > Any sensible implementation is ok for me. Usually, stuff for root > group is in the bfqd. > I'll try to do implement that way, Thanks, Kuai > Thanks, > Paolo > >> Thanks, >> Kuai > > . >