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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 8E91FC28CBC for ; Thu, 30 Apr 2020 13:53:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 617E120873 for ; Thu, 30 Apr 2020 13:53:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588254829; bh=r7xi7xjZ6Fsdw2v6jyWidSzLPNaMqwe4mVlfuLkfu6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xsCx87Akw5PAcmqwcvftzXwqLZGlro/jbTQAeJB0UdglcySyhdI2OZXI03BhG4I6K NiWbFC87RMQRqtpO9cGMyYPZh6HxuSEnzKqZQk/LmHl5fL+6jSpKj/BRtxsFPRp+r0 qk1LOOOdB6dnOB8ukeOTHPq53CL6TMuDW0Nld7fA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728808AbgD3Nxs (ORCPT ); Thu, 30 Apr 2020 09:53:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:34738 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728637AbgD3NxJ (ORCPT ); Thu, 30 Apr 2020 09:53:09 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E3E5024954; Thu, 30 Apr 2020 13:53:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588254788; bh=r7xi7xjZ6Fsdw2v6jyWidSzLPNaMqwe4mVlfuLkfu6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CCm0d6nR9UYfJIpcYZHq6HnJY2KxZidjTcV5KyQgcTS/aDSl8GGkQWuRqBh8Lulza 5HRTjIq05yVpLNooe38UY0n0FWPb/EzGwBbTY9Lk3Utvt+qfZrdMlpjSD+aHnGeQmr DjkxDUKBH4JtP0ucmZ24IbGttsPGDHGqnt0q8m38= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Quentin Perret , Chitti Babu Theegala , Peter Zijlstra , Patrick Bellasi , Dietmar Eggemann , Sasha Levin Subject: [PATCH AUTOSEL 5.4 44/57] sched/core: Fix reset-on-fork from RT with uclamp Date: Thu, 30 Apr 2020 09:52:05 -0400 Message-Id: <20200430135218.20372-44-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200430135218.20372-1-sashal@kernel.org> References: <20200430135218.20372-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Quentin Perret [ Upstream commit eaf5a92ebde5bca3bb2565616115bd6d579486cd ] uclamp_fork() resets the uclamp values to their default when the reset-on-fork flag is set. It also checks whether the task has a RT policy, and sets its uclamp.min to 1024 accordingly. However, during reset-on-fork, the task's policy is lowered to SCHED_NORMAL right after, hence leading to an erroneous uclamp.min setting for the new task if it was forked from RT. Fix this by removing the unnecessary check on rt_task() in uclamp_fork() as this doesn't make sense if the reset-on-fork flag is set. Fixes: 1a00d999971c ("sched/uclamp: Set default clamps for RT tasks") Reported-by: Chitti Babu Theegala Signed-off-by: Quentin Perret Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Patrick Bellasi Reviewed-by: Dietmar Eggemann Link: https://lkml.kernel.org/r/20200416085956.217587-1-qperret@google.com Signed-off-by: Sasha Levin --- kernel/sched/core.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 195d0019e6bb5..e99d326fa5693 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1233,13 +1233,8 @@ static void uclamp_fork(struct task_struct *p) return; for_each_clamp_id(clamp_id) { - unsigned int clamp_value = uclamp_none(clamp_id); - - /* By default, RT tasks always get 100% boost */ - if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN)) - clamp_value = uclamp_none(UCLAMP_MAX); - - uclamp_se_set(&p->uclamp_req[clamp_id], clamp_value, false); + uclamp_se_set(&p->uclamp_req[clamp_id], + uclamp_none(clamp_id), false); } } -- 2.20.1