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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 AEDB0C43331 for ; Fri, 6 Sep 2019 03:13:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A88AC206DE for ; Fri, 6 Sep 2019 03:13:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="b8K0dwSO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404398AbfIFDNJ (ORCPT ); Thu, 5 Sep 2019 23:13:09 -0400 Received: from mail.efficios.com ([167.114.142.138]:40124 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391259AbfIFDNJ (ORCPT ); Thu, 5 Sep 2019 23:13:09 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 0A41532CD7E; Thu, 5 Sep 2019 23:13:08 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id aayVk7JPbFuJ; Thu, 5 Sep 2019 23:13:07 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 5A2DB32CD78; Thu, 5 Sep 2019 23:13:07 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 5A2DB32CD78 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1567739587; bh=7Srmn34tOeDbJzYM48SWBd4hahO+yo5hhHH3R10GHHo=; h=From:To:Date:Message-Id; b=b8K0dwSOPkr9c1xMqkrNDNl2ZxxygJer6Cq8atILpglXPX1lDdxBudcarGU1EzFWw fVvO3kbCJa70pN40/ykfJMaOostIjxuOqoafXPaaD7snB7rUuUoRK66kijboyd1RS9 WUwSGnvsUIbVWVycioK64dKBoleiEgmZ3nwn9RjYo/33SLQ3Ye5T1Ltcy2RVbfSH5E BopLIJbY+0d9A01teWiR/KEfnTe403TVK9XcCszSVM+LG6nlqsUOptlCG/E088V1Qm SP3EMCfBkt5mwfbYU5XER7ZNvgusF0BbGhg/4bZWWkoaPdiDnWNa5SF4f9MThaxZEm srlsnhQpFNYdw== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id x5jTZ3oxQ--h; Thu, 5 Sep 2019 23:13:07 -0400 (EDT) Received: from localhost.localdomain (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by mail.efficios.com (Postfix) with ESMTPSA id 1C10532CD68; Thu, 5 Sep 2019 23:13:07 -0400 (EDT) From: Mathieu Desnoyers To: Peter Zijlstra , "Paul E. McKenney" Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Oleg Nesterov , "Eric W. Biederman" , Linus Torvalds , Russell King - ARM Linux admin , Chris Metcalf , Christoph Lameter , Kirill Tkhai , Mike Galbraith , Thomas Gleixner , Mathieu Desnoyers Subject: [RFC PATCH 2/4] Cleanup: sched/membarrier: remove redundant check Date: Thu, 5 Sep 2019 23:12:58 -0400 Message-Id: <20190906031300.1647-3-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190906031300.1647-1-mathieu.desnoyers@efficios.com> References: <20190906031300.1647-1-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Checking that the number of threads is 1 is redundant with checking mm_users == 1. Suggested-by: Oleg Nesterov Signed-off-by: Mathieu Desnoyers Cc: "Paul E. McKenney" Cc: Peter Zijlstra Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Linus Torvalds Cc: Russell King - ARM Linux admin Cc: Chris Metcalf Cc: Christoph Lameter Cc: Kirill Tkhai Cc: Mike Galbraith Cc: Thomas Gleixner Cc: Ingo Molnar --- kernel/sched/membarrier.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 5110d91b1b0e..7e0a0d6535f3 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -186,7 +186,7 @@ static int membarrier_register_global_expedited(void) MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY) return 0; atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED, &mm->membarrier_state); - if (atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1) { + if (atomic_read(&mm->mm_users) == 1) { /* * For single mm user, single threaded process, we can * simply issue a memory barrier after setting @@ -232,7 +232,7 @@ static int membarrier_register_private_expedited(int flags) if (flags & MEMBARRIER_FLAG_SYNC_CORE) atomic_or(MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE, &mm->membarrier_state); - if (!(atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1)) { + if (atomic_read(&mm->mm_users) != 1) { /* * Ensure all future scheduler executions will observe the * new thread flag state for this process. -- 2.17.1