Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752553AbdFNRQo (ORCPT ); Wed, 14 Jun 2017 13:16:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:54000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752499AbdFNRQl (ORCPT ); Wed, 14 Jun 2017 13:16:41 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ED6AA239DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org MIME-Version: 1.0 In-Reply-To: <06ea73a2-f724-5b3e-5d9d-143d91ba94ae@intel.com> References: <65ee83f8ef7259053e117355b0597b03ce096e07.1497415951.git.luto@kernel.org> <06ea73a2-f724-5b3e-5d9d-143d91ba94ae@intel.com> From: Andy Lutomirski Date: Wed, 14 Jun 2017 10:16:19 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 03/10] x86/mm: Give each mm TLB flush generation a unique ID To: Dave Hansen Cc: Andy Lutomirski , X86 ML , "linux-kernel@vger.kernel.org" , Borislav Petkov , Linus Torvalds , Andrew Morton , Mel Gorman , "linux-mm@kvack.org" , Nadav Amit , Rik van Riel , Arjan van de Ven , Peter Zijlstra Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 521 Lines: 14 On Wed, Jun 14, 2017 at 8:54 AM, Dave Hansen wrote: > On 06/13/2017 09:56 PM, Andy Lutomirski wrote: >> typedef struct { >> + /* >> + * ctx_id uniquely identifies this mm_struct. A ctx_id will never >> + * be reused, and zero is not a valid ctx_id. >> + */ >> + u64 ctx_id; > > Ahh, and you need this because an mm itself might get reused by being > freed and reallocated? Exactly. I didn't want to have to zap the data structures on each CPU every time an mm is freed.