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 E4842C4724C for ; Thu, 30 Apr 2020 14:09:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4AC3206D9 for ; Thu, 30 Apr 2020 14:09:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588255762; bh=MyBj4qtov3HG2b8+oAL8ufv3SgQnm24ehJlL9VKrxsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VNDK/HDGsFDs/1nPEGPLe/jL3KRKFw2kNokr8Qhjg4ay5sxgoXWYcTAVxLjAzCErW FXBdK2LMmti5j0CGq8R15caXy9uq1PhrrLIeNj8xujyCxGRz7yJ7RBl4HLi73aIcn9 xSkFE1g+Ybkw5cyBWVz2bRKQqqVbi32CVfdkvTlI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728231AbgD3Nvy (ORCPT ); Thu, 30 Apr 2020 09:51:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:60680 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728228AbgD3Nvx (ORCPT ); Thu, 30 Apr 2020 09:51:53 -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 9A624208D5; Thu, 30 Apr 2020 13:51:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588254713; bh=MyBj4qtov3HG2b8+oAL8ufv3SgQnm24ehJlL9VKrxsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M2C7WagK/52zOTcEsd7IY/XNvZedELvFw3EsBD9ua+wB7CSU+0m9Ut7bTBihEzmjD cnFr8PEp/V+cNXKQhp6QEJThSzJTd5+jbdgtENT3v5o12gCbYisD2mEQmUQ9PXlSco fpxwoAARYeeFv4KJPidNkJ77Lu8Jz+ZzPJSeNVhQ= 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 5.6 61/79] sched/core: Fix reset-on-fork from RT with uclamp Date: Thu, 30 Apr 2020 09:50:25 -0400 Message-Id: <20200430135043.19851-61-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200430135043.19851-1-sashal@kernel.org> References: <20200430135043.19851-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 da8a194702185..3dd6756973013 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1239,13 +1239,8 @@ 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