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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 AAE9CC04E53 for ; Wed, 15 May 2019 11:12:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B25320644 for ; Wed, 15 May 2019 11:12:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557918743; bh=bvmCFZAcCNHnBodtaxWi016DoRHs+DDGWr67rN5v8I8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Hd/9xgMVtLS/VK389cRXpSNKU6IBWGPIXXfHzL659N9JbbBBvn4P7hI2nXar9dMfU 79nDp4bW6h3RSLHc9qnNXb6AkVK/4FMf3rMu5UNOdlAsYnaa2WeDwEg6HTiWUXNRrj /lmfCJhJOjzvdFaM9RwysnBiMyhp6WeHHoKMQWsU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729755AbfEOLMW (ORCPT ); Wed, 15 May 2019 07:12:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:47296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729744AbfEOLMS (ORCPT ); Wed, 15 May 2019 07:12:18 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1080D2166E; Wed, 15 May 2019 11:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557918737; bh=bvmCFZAcCNHnBodtaxWi016DoRHs+DDGWr67rN5v8I8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N5FwYXV9HZT3aSYUPgQuFeYtULg0xt7uGX3We3boCLOBrf3+w2DpD72buaPS0tiyn UK+kOvb2C5z9fHaUqHQZGqw+PIz4vH7HrCfpvuWGLSXf2Kl+0LiHaZdA5BUPzQyXBV jxBJ8ViuZwUL2uyi923PVGz11cvCtq16hWY3jY2g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings , Thomas Gleixner , Ingo Molnar , "Peter Zijlstra (Intel)" , Konrad Rzeszutek Wilk Subject: [PATCH 4.4 209/266] sched: Add sched_smt_active() Date: Wed, 15 May 2019 12:55:16 +0200 Message-Id: <20190515090730.037812794@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515090722.696531131@linuxfoundation.org> References: <20190515090722.696531131@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ben Hutchings Add the sched_smt_active() function needed for some x86 speculation mitigations. This was introduced upstream by commits 1b568f0aabf2 "sched/core: Optimize SCHED_SMT", ba2591a5993e "sched/smt: Update sched_smt_present at runtime", c5511d03ec09 "sched/smt: Make sched_smt_present track topology", and 321a874a7ef8 "sched/smt: Expose sched_smt_present static key". The upstream implementation uses the static_key_{disable,enable}_cpuslocked() functions, which aren't practical to backport. Signed-off-by: Ben Hutchings Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra (Intel) Cc: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- include/linux/sched/smt.h | 18 ++++++++++++++++++ kernel/sched/core.c | 24 ++++++++++++++++++++++++ kernel/sched/sched.h | 1 + 3 files changed, 43 insertions(+) create mode 100644 include/linux/sched/smt.h --- /dev/null +++ b/include/linux/sched/smt.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SCHED_SMT_H +#define _LINUX_SCHED_SMT_H + +#include + +#ifdef CONFIG_SCHED_SMT +extern atomic_t sched_smt_present; + +static __always_inline bool sched_smt_active(void) +{ + return atomic_read(&sched_smt_present); +} +#else +static inline bool sched_smt_active(void) { return false; } +#endif + +#endif --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5610,6 +5610,10 @@ static void set_cpu_rq_start_time(void) rq->age_stamp = sched_clock_cpu(cpu); } +#ifdef CONFIG_SCHED_SMT +atomic_t sched_smt_present = ATOMIC_INIT(0); +#endif + static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { @@ -5626,11 +5630,23 @@ static int sched_cpu_active(struct notif * set_cpu_online(). But it might not yet have marked itself * as active, which is essential from here on. */ +#ifdef CONFIG_SCHED_SMT + /* + * When going up, increment the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + atomic_inc(&sched_smt_present); +#endif set_cpu_active(cpu, true); stop_machine_unpark(cpu); return NOTIFY_OK; case CPU_DOWN_FAILED: +#ifdef CONFIG_SCHED_SMT + /* Same as for CPU_ONLINE */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + atomic_inc(&sched_smt_present); +#endif set_cpu_active(cpu, true); return NOTIFY_OK; @@ -5645,7 +5661,15 @@ static int sched_cpu_inactive(struct not switch (action & ~CPU_TASKS_FROZEN) { case CPU_DOWN_PREPARE: set_cpu_active((long)hcpu, false); +#ifdef CONFIG_SCHED_SMT + /* + * When going down, decrement the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask((long)hcpu)) == 2) + atomic_dec(&sched_smt_present); +#endif return NOTIFY_OK; + default: return NOTIFY_DONE; } --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2,6 +2,7 @@ #include #include #include +#include #include #include #include