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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,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 13012C43441 for ; Wed, 28 Nov 2018 14:26:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8749208E7 for ; Wed, 28 Nov 2018 14:26:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8749208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728523AbeK2B2m (ORCPT ); Wed, 28 Nov 2018 20:28:42 -0500 Received: from terminus.zytor.com ([198.137.202.136]:41881 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727726AbeK2B2l (ORCPT ); Wed, 28 Nov 2018 20:28:41 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wASEOxXd2322672 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 28 Nov 2018 06:24:59 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wASEOxcn2322666; Wed, 28 Nov 2018 06:24:59 -0800 Date: Wed, 28 Nov 2018 06:24:59 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Thomas Gleixner Message-ID: Cc: keescook@chromium.org, ak@linux.intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, casey.schaufler@intel.com, asit.k.mallick@intel.com, jcm@redhat.com, mingo@kernel.org, dave.hansen@intel.com, gregkh@linuxfoundation.org, luto@kernel.org, aarcange@redhat.com, jkosina@suse.cz, torvalds@linux-foundation.org, longman9394@gmail.com, dwmw@amazon.co.uk, hpa@zytor.com, david.c.stewart@intel.com, arjan@linux.intel.com, jpoimboe@redhat.com, peterz@infradead.org, thomas.lendacky@amd.com, tim.c.chen@linux.intel.com Reply-To: david.c.stewart@intel.com, hpa@zytor.com, dwmw@amazon.co.uk, torvalds@linux-foundation.org, longman9394@gmail.com, tim.c.chen@linux.intel.com, thomas.lendacky@amd.com, peterz@infradead.org, arjan@linux.intel.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, casey.schaufler@intel.com, asit.k.mallick@intel.com, keescook@chromium.org, tglx@linutronix.de, ak@linux.intel.com, aarcange@redhat.com, jkosina@suse.cz, gregkh@linuxfoundation.org, luto@kernel.org, jcm@redhat.com, mingo@kernel.org, dave.hansen@intel.com In-Reply-To: <20181125185004.337452245@linutronix.de> References: <20181125185004.337452245@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/Kconfig: Select SCHED_SMT if SMP enabled Git-Commit-ID: dbe733642e01dd108f71436aaea7b328cb28fd87 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: dbe733642e01dd108f71436aaea7b328cb28fd87 Gitweb: https://git.kernel.org/tip/dbe733642e01dd108f71436aaea7b328cb28fd87 Author: Thomas Gleixner AuthorDate: Sun, 25 Nov 2018 19:33:37 +0100 Committer: Thomas Gleixner CommitDate: Wed, 28 Nov 2018 11:57:07 +0100 x86/Kconfig: Select SCHED_SMT if SMP enabled CONFIG_SCHED_SMT is enabled by all distros, so there is not a real point to have it configurable. The runtime overhead in the core scheduler code is minimal because the actual SMT scheduling parts are conditional on a static key. This allows to expose the scheduler's SMT state static key to the speculation control code. Alternatively the scheduler's static key could be made always available when CONFIG_SMP is enabled, but that's just adding an unused static key to every other architecture for nothing. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jiri Kosina Cc: Tom Lendacky Cc: Josh Poimboeuf Cc: Andrea Arcangeli Cc: David Woodhouse Cc: Tim Chen Cc: Andi Kleen Cc: Dave Hansen Cc: Casey Schaufler Cc: Asit Mallick Cc: Arjan van de Ven Cc: Jon Masters Cc: Waiman Long Cc: Greg KH Cc: Dave Stewart Cc: Kees Cook Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185004.337452245@linutronix.de --- arch/x86/Kconfig | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index b5286ad2a982..8689e794a43c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1000,13 +1000,7 @@ config NR_CPUS to the kernel image. config SCHED_SMT - bool "SMT (Hyperthreading) scheduler support" - depends on SMP - ---help--- - SMT scheduler support improves the CPU scheduler's decision making - when dealing with Intel Pentium 4 chips with HyperThreading at a - cost of slightly increased overhead in some places. If unsure say - N here. + def_bool y if SMP config SCHED_MC def_bool y