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=-14.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 C0B9EC4346E for ; Tue, 29 Sep 2020 07:57:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BB7520773 for ; Tue, 29 Sep 2020 07:57:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="u+FXIle1"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="L9iCT9Jw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727763AbgI2H5V (ORCPT ); Tue, 29 Sep 2020 03:57:21 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:44402 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727674AbgI2H4y (ORCPT ); Tue, 29 Sep 2020 03:56:54 -0400 Date: Tue, 29 Sep 2020 07:56:52 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1601366212; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=U7CfbqTIu4ffuB5Vk25yLn8JniTSOZFWZqsZFDKP7Fs=; b=u+FXIle1pdoHwLi9Ush6KJCEcTsEd8tNis5pePfTQoRqzl4QVfZ7wawc815yaUsM9JJrXk lDNGmp1xo3t8RcFWYwXovVB4wP5jJQX0VOnCpZv9rrZ30oKBg+Lia2GVOQqDOs2dXDsvFc BZASb4cG+fe5zOekJYU3FLVFQaJ7EJFFMXaWCTVInC68FDWYO+B0PuNo5zuiS1w1Gvy5EH Y+tGGMzTiJQjHmoPCE8wy+6emezf5/HAZ13nm11znUuL1SWR7Vjzdgq+PMZkMnli+Wb515 YRCxxIoqtntm3mcJ46xOXn1zzCGWLM6RbF679piarMYc7v1mrQqw2GoWlkYIsQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1601366212; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=U7CfbqTIu4ffuB5Vk25yLn8JniTSOZFWZqsZFDKP7Fs=; b=L9iCT9JwGGLNEhfvYNl5lTLZbr5ncxKM1o5wD97NFPROJreH8CS1sMtun8V9kA5HzXkrMY rMHaXJa8A4WkADAw== From: "tip-bot2 for Daniel Bristot de Oliveira" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/rt: Disable RT_RUNTIME_SHARE by default Cc: Daniel Bristot de Oliveira , "Peter Zijlstra (Intel)" , Wei Wang , x86 , LKML In-Reply-To: References: MIME-Version: 1.0 Message-ID: <160136621203.7002.9402784269901680382.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 2586af1ac187f6b3a50930a4e33497074e81762d Gitweb: https://git.kernel.org/tip/2586af1ac187f6b3a50930a4e33497074e81762d Author: Daniel Bristot de Oliveira AuthorDate: Mon, 21 Sep 2020 16:39:49 +02:00 Committer: Peter Zijlstra CommitterDate: Fri, 25 Sep 2020 14:23:24 +02:00 sched/rt: Disable RT_RUNTIME_SHARE by default The RT_RUNTIME_SHARE sched feature enables the sharing of rt_runtime between CPUs, allowing a CPU to run a real-time task up to 100% of the time while leaving more space for non-real-time tasks to run on the CPU that lend rt_runtime. The problem is that a CPU can easily borrow enough rt_runtime to allow a spinning rt-task to run forever, starving per-cpu tasks like kworkers, which are non-real-time by design. This patch disables RT_RUNTIME_SHARE by default, avoiding this problem. The feature will still be present for users that want to enable it, though. Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Peter Zijlstra (Intel) Tested-by: Wei Wang Link: https://lkml.kernel.org/r/b776ab46817e3db5d8ef79175fa0d71073c051c7.1600697903.git.bristot@redhat.com --- kernel/sched/features.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 7481cd9..68d369c 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -77,7 +77,7 @@ SCHED_FEAT(WARN_DOUBLE_CLOCK, false) SCHED_FEAT(RT_PUSH_IPI, true) #endif -SCHED_FEAT(RT_RUNTIME_SHARE, true) +SCHED_FEAT(RT_RUNTIME_SHARE, false) SCHED_FEAT(LB_MIN, false) SCHED_FEAT(ATTACH_AGE_LOAD, true)