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=-11.8 required=3.0 tests=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 54DB3C4360C for ; Fri, 27 Sep 2019 08:11:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35A8D2146E for ; Fri, 27 Sep 2019 08:11:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727129AbfI0ILX (ORCPT ); Fri, 27 Sep 2019 04:11:23 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:45319 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727090AbfI0ILV (ORCPT ); Fri, 27 Sep 2019 04:11:21 -0400 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iDlKt-0005aj-9A; Fri, 27 Sep 2019 10:10:43 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id D80E71C0440; Fri, 27 Sep 2019 10:10:42 +0200 (CEST) Date: Fri, 27 Sep 2019 08:10:42 -0000 From: "tip-bot2 for Mathieu Desnoyers" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/urgent] sched/membarrier: Skip IPIs when mm->mm_users == 1 Cc: Mathieu Desnoyers , "Peter Zijlstra (Intel)" , Chris Metcalf , Christoph Lameter , "Eric W. Biederman" , Kirill Tkhai , Linus Torvalds , Mike Galbraith , Oleg Nesterov , "Paul E. McKenney" , "Russell King - ARM Linux admin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , linux-kernel@vger.kernel.org In-Reply-To: <20190919173705.2181-7-mathieu.desnoyers@efficios.com> References: <20190919173705.2181-7-mathieu.desnoyers@efficios.com> MIME-Version: 1.0 Message-ID: <156957184275.9866.9051290983348883537.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/urgent branch of tip: Commit-ID: c6d68c1c4a4d6611fc0f8145d764226571d737ca Gitweb: https://git.kernel.org/tip/c6d68c1c4a4d6611fc0f8145d764226571d737ca Author: Mathieu Desnoyers AuthorDate: Thu, 19 Sep 2019 13:37:04 -04:00 Committer: Ingo Molnar CommitterDate: Wed, 25 Sep 2019 17:42:31 +02:00 sched/membarrier: Skip IPIs when mm->mm_users == 1 If there is only a single mm_user for the mm, the private expedited membarrier command can skip the IPIs, because only a single thread is using the mm. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Cc: Chris Metcalf Cc: Christoph Lameter Cc: Eric W. Biederman Cc: Kirill Tkhai Cc: Linus Torvalds Cc: Mike Galbraith Cc: Oleg Nesterov Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Russell King - ARM Linux admin Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190919173705.2181-7-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar --- kernel/sched/membarrier.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 070cf43..fced54a 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -145,20 +145,21 @@ static int membarrier_private_expedited(int flags) int cpu; bool fallback = false; cpumask_var_t tmpmask; + struct mm_struct *mm = current->mm; if (flags & MEMBARRIER_FLAG_SYNC_CORE) { if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE)) return -EINVAL; - if (!(atomic_read(¤t->mm->membarrier_state) & + if (!(atomic_read(&mm->membarrier_state) & MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY)) return -EPERM; } else { - if (!(atomic_read(¤t->mm->membarrier_state) & + if (!(atomic_read(&mm->membarrier_state) & MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY)) return -EPERM; } - if (num_online_cpus() == 1) + if (atomic_read(&mm->mm_users) == 1 || num_online_cpus() == 1) return 0; /* @@ -194,7 +195,7 @@ static int membarrier_private_expedited(int flags) continue; rcu_read_lock(); p = rcu_dereference(cpu_rq(cpu)->curr); - if (p && p->mm == current->mm) { + if (p && p->mm == mm) { if (!fallback) __cpumask_set_cpu(cpu, tmpmask); else