From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f199.google.com (mail-ig0-f199.google.com [209.85.213.199]) by kanga.kvack.org (Postfix) with ESMTP id 0B9346B007E for ; Thu, 9 Jun 2016 13:24:39 -0400 (EDT) Received: by mail-ig0-f199.google.com with SMTP id lp2so62321178igb.3 for ; Thu, 09 Jun 2016 10:24:39 -0700 (PDT) Received: from mail-oi0-x22b.google.com (mail-oi0-x22b.google.com. [2607:f8b0:4003:c06::22b]) by mx.google.com with ESMTPS id 62si3478105ots.136.2016.06.09.10.24.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 Jun 2016 10:24:38 -0700 (PDT) Received: by mail-oi0-x22b.google.com with SMTP id p204so74077333oih.3 for ; Thu, 09 Jun 2016 10:24:38 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <8D80C93B-3DD6-469B-90D6-FBC71B917EAD@gmail.com> References: <95a853538da28c64dfc877c60549ec79ed7a5d69.1452294700.git.luto@kernel.org> <8D80C93B-3DD6-469B-90D6-FBC71B917EAD@gmail.com> From: Andy Lutomirski Date: Thu, 9 Jun 2016 10:24:18 -0700 Message-ID: Subject: Re: [RFC 05/13] x86/mm: Add barriers and document switch_mm-vs-flush synchronization Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Nadav Amit Cc: Andy Lutomirski , X86 ML , LKML , Borislav Petkov , Brian Gerst , Dave Hansen , Oleg Nesterov , "linux-mm@kvack.org" On Fri, Jun 3, 2016 at 10:42 AM, Nadav Amit wrote: > Following this patch, if (current->active_mm !=3D mm), flush_tlb_page() s= till > doesn=E2=80=99t call smp_mb() before checking mm_cpumask(mm). > > In contrast, flush_tlb_mm_range() does call smp_mb(). > > Is there a reason for this discrepancy? Not that I can remember. Is the remote flush case likely to be racy? --Andy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org