Received: by 2002:a05:6a10:1d13:0:0:0:0 with SMTP id pp19csp476248pxb; Wed, 18 Aug 2021 06:47:57 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw+tKHomUbXUGaJwCZPS6t8sseSJTQJC43zAqdWjMZLlX4ba7tgPQm4l1OZbo17k+q+yot0 X-Received: by 2002:a05:6402:2029:: with SMTP id ay9mr10114587edb.236.1629294477451; Wed, 18 Aug 2021 06:47:57 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1629294477; cv=none; d=google.com; s=arc-20160816; b=dkiRjWRgzBUhESUUQcqDunINPD7wNtWbTh25dCXU74wiopGdMwdu3Sjtr20qFpfbBf piXO7a9DJPZM5aJcZAT/SDQuiBtxZioOn1ePJnVOXKAzs3KIdAA/RbWiDmfZzxmwqf8g BLjJPVgs2uvYLwj8Jr3Kcb0wMYlH6aEevRE45xlzmBfUSpci376siyWw2Ja9FQb9Lnvr dUojqLFNxoW9Kdxm0lTPjwIM9DT0DXsGCbPsTyDnL4eRb7mIGe8GW2FB+9M6rGTmY0iW 3y5qc1vPCnKsH3Bhu67Om7WHfoQeVyM1TvpzYeH/Hzx0WP2nNQEFYVUX0YJnmfh3baNM EnuQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version:date :message-id:subject:references:in-reply-to:cc:to:from; bh=x+igDzLldHj8Cfaw0w6v5Tk7hNEE5R58Z1iUs3i5UYk=; b=x25yjlwR5i7U+0Q6Hw9BgZHnAKsA4sWmOuuw6capWFQVlEsMh3b0B3NyLJqKi/ajBx 6tXr748K7nfTX6sX/wlp1fSu2tUX7qP9RB9vXXjfCzeoQvaosY8f3VZObmuCi1Hu74i5 DD2Me1nQdK/paqEU2CUE6mukQ2Xujc/QuVzyWYTKYWGMiZTPiOEEbjO83/kGU5Kn1bFA KrKUCbPhTSJSzt0SZo/MpfUPCGqKoFUtgu5vYYq0r1Y7OtjGsWAn07VyeO9ovIuXzwNl NpEHeMjISi5ioa7nSowsxUU2fku+QVTe2zdWIFgqIdky4MtPD1ieBqAHwNgsxuEAhi8C 4PHQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id 4si5490544ejm.546.2021.08.18.06.47.33; Wed, 18 Aug 2021 06:47:57 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237168AbhHRNqg (ORCPT + 99 others); Wed, 18 Aug 2021 09:46:36 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:35127 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237097AbhHRNqc (ORCPT ); Wed, 18 Aug 2021 09:46:32 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 4GqTgl0rVwz9sRf; Wed, 18 Aug 2021 23:45:54 +1000 (AEST) From: Michael Ellerman To: Christophe Leroy , Benjamin Herrenschmidt , Michael Ellerman , Paul Mackerras Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org In-Reply-To: References: Subject: Re: [PATCH] powerpc/non-smp: Inconditionaly call smp_mb() on switch_mm Message-Id: <162929391862.3619265.13703317304945129576.b4-ty@ellerman.id.au> Date: Wed, 18 Aug 2021 23:38:38 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 5 Jul 2021 12:00:50 +0000 (UTC), Christophe Leroy wrote: > Commit 3ccfebedd8cf ("powerpc, membarrier: Skip memory barrier in > switch_mm()") added some logic to skip the smp_mb() in > switch_mm_irqs_off() before the call to switch_mmu_context(). > > However, on non SMP smp_mb() is just a compiler barrier and doing > it inconditionaly is simpler than the logic used to check > whether the barrier is needed or not. > > [...] Applied to powerpc/next. [1/1] powerpc/non-smp: Inconditionaly call smp_mb() on switch_mm https://git.kernel.org/powerpc/c/c8a6d91005343dea0d53be0ff0620c66934dcd44 cheers