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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 1B96EC2D0DB for ; Sat, 25 Jan 2020 16:15:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1C952071A for ; Sat, 25 Jan 2020 16:15:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="UAKv0n4b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726448AbgAYQPU (ORCPT ); Sat, 25 Jan 2020 11:15:20 -0500 Received: from forwardcorp1p.mail.yandex.net ([77.88.29.217]:38626 "EHLO forwardcorp1p.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725843AbgAYQPT (ORCPT ); Sat, 25 Jan 2020 11:15:19 -0500 Received: from mxbackcorp1g.mail.yandex.net (mxbackcorp1g.mail.yandex.net [IPv6:2a02:6b8:0:1402::301]) by forwardcorp1p.mail.yandex.net (Yandex) with ESMTP id 8E8112E12DF; Sat, 25 Jan 2020 19:15:17 +0300 (MSK) Received: from myt5-70c90f7d6d7d.qloud-c.yandex.net (myt5-70c90f7d6d7d.qloud-c.yandex.net [2a02:6b8:c12:3e2c:0:640:70c9:f7d]) by mxbackcorp1g.mail.yandex.net (mxbackcorp/Yandex) with ESMTP id UeYdkOdi7d-FG0umoYZ; Sat, 25 Jan 2020 19:15:17 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1579968917; bh=B6sdDPyNVdIg67M4l3o5kVQhl9OzerZH56rY3+HDr4I=; h=In-Reply-To:Message-ID:From:Date:References:To:Subject:Cc; b=UAKv0n4bO5cnIMTe4niKoA+u7+l3lsZcK6KWcEMUpA7TtjoN7i05ZsU+SatVmu7Pp T5Gkaf28T6A//e6DQ6UqDaaPHfaVNjMFmcPxdC6pB5dlixf9MEJFaklsrN8NyZLLIW MDW+bfv+qTy48DUVAaAauHuEnXJEGa/h7DWM4+Ho= Authentication-Results: mxbackcorp1g.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from unknown (unknown [2a02:6b8:b080:6910::1:5]) by myt5-70c90f7d6d7d.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id AJZYip8hK8-FGWmlBa6; Sat, 25 Jan 2020 19:15:16 +0300 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client certificate not present) Subject: Re: [PATCH] sched/rt: optimize checking group rt scheduler constraints To: Cyrill Gorcunov Cc: linux-kernel@vger.kernel.org, Juri Lelli , Vincent Guittot , Peter Zijlstra , Steven Rostedt , Ben Segall , Ingo Molnar , Mel Gorman , Dietmar Eggemann References: <157996383820.4651.11292439232549211693.stgit@buzz> <20200125153211.GP2437@uranus> From: Konstantin Khlebnikov Message-ID: <417d11b4-d5a2-96c2-8007-5e8f90a422cb@yandex-team.ru> Date: Sat, 25 Jan 2020 19:15:16 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200125153211.GP2437@uranus> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-CA Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/01/2020 18.32, Cyrill Gorcunov wrote: > On Sat, Jan 25, 2020 at 05:50:38PM +0300, Konstantin Khlebnikov wrote: > ... >> -/* Must be called with tasklist_lock held */ >> static inline int tg_has_rt_tasks(struct task_group *tg) >> { >> - struct task_struct *g, *p; >> + struct task_struct *task; >> + struct css_task_iter it; >> + int ret = 0; >> >> /* >> * Autogroups do not have RT tasks; see autogroup_create(). >> @@ -2407,12 +2408,12 @@ static inline int tg_has_rt_tasks(struct task_group *tg) >> if (task_group_is_autogroup(tg)) >> return 0; >> >> - for_each_process_thread(g, p) { >> - if (rt_task(p) && task_group(p) == tg) >> - return 1; >> - } >> + css_task_iter_start(&tg->css, 0, &it); >> + while (!ret && (task = css_task_iter_next(&it))) >> + ret |= rt_task(task); > > Plain 'ret = rt_task(task);' won't work? Should work too =) > >> + css_task_iter_end(&it); >> >> - return 0; >> + return ret; >> }