From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [RFC PATCH v3] sparc64: Add support for Application Data Integrity (ADI) Date: Fri, 6 Jan 2017 09:22:13 -0700 Message-ID: References: <8612e7db-97c5-f757-0aae-24c3acedbc29@oracle.com> <2c0502d0-20ef-44ac-db5b-7f651a70b978@linux.intel.com> <5a0270ea-b29a-0751-a27f-2412a8588561@oracle.com> <7532a1d6-6562-b10b-dacd-931cb2a9e536@linux.intel.com> <92d55a69-b400-8461-53a1-d505de089700@oracle.com> <75c31c99-cff7-72dc-f593-012fe5acd405@linux.intel.com> <7fbc4ca1-22ef-8ef5-5c1b-dd075852e512@oracle.com> <20170106091934.GF5556@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: owner-linux-mm@kvack.org To: Dave Hansen , Michal Hocko Cc: Rob Gardner , davem@davemloft.net, corbet@lwn.net, arnd@arndb.de, akpm@linux-foundation.org, hpa@zytor.com, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com, chris.hyser@oracle.com, tushar.n.dave@oracle.com, sowmini.varadhan@oracle.com, mike.kravetz@oracle.com, adam.buchbinder@gmail.com, minchan@kernel.org, hughd@google.com, kirill.shutemov@linux.intel.com, keescook@chromium.org, allen.pais@oracle.com, aryabinin@virtuozzo.com, atish.patra@oracle.com, joe@perches.com, pmladek@suse.com, jslaby@suse.cz, cmetcalf@mellanox.com, paul.gortmaker@windriver.com, jmarchan@redhat.com, lstoakes@gmail.com, 0x7f454c46@gmail.com, vbabka@suse.cz, tglx@linutronix.de, mingo@redhat.com, dan.j.williams@intel.com, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net, vdavydov.dev List-Id: linux-arch.vger.kernel.org On 01/06/2017 08:36 AM, Dave Hansen wrote: > On 01/06/2017 07:32 AM, Khalid Aziz wrote: >> I agree with you on simplicity first. Subpage granularity is complex, >> but the architecture allows for subpage granularity. Maybe the right >> approach is to support this at page granularity first for swappable >> pages and then expand to subpage granularity in a subsequent patch? >> Pages locked in memory can already use subpage granularity with my patch. > > What do you mean by "locked in memory"? mlock()'d memory can still be > migrated around and still requires "swap" ptes, for instance. You are right. Page migration can invalidate subpage granularity even for locked pages. Is it possible to use cpusets to keep a task and its memory locked on a single node? Just wondering if there are limited cases where subpage granularity could work without supporting subpage granularity for tags in swap. It still sounds like the right thing to do is to get a reliable implementation in place with page size granularity and then add the complexity of subpage granularity. Thanks, Khalid -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:34080 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967312AbdAFQXQ (ORCPT ); Fri, 6 Jan 2017 11:23:16 -0500 Subject: Re: [RFC PATCH v3] sparc64: Add support for Application Data Integrity (ADI) References: <8612e7db-97c5-f757-0aae-24c3acedbc29@oracle.com> <2c0502d0-20ef-44ac-db5b-7f651a70b978@linux.intel.com> <5a0270ea-b29a-0751-a27f-2412a8588561@oracle.com> <7532a1d6-6562-b10b-dacd-931cb2a9e536@linux.intel.com> <92d55a69-b400-8461-53a1-d505de089700@oracle.com> <75c31c99-cff7-72dc-f593-012fe5acd405@linux.intel.com> <7fbc4ca1-22ef-8ef5-5c1b-dd075852e512@oracle.com> <20170106091934.GF5556@dhcp22.suse.cz> From: Khalid Aziz Message-ID: Date: Fri, 6 Jan 2017 09:22:13 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Dave Hansen , Michal Hocko Cc: Rob Gardner , davem@davemloft.net, corbet@lwn.net, arnd@arndb.de, akpm@linux-foundation.org, hpa@zytor.com, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com, chris.hyser@oracle.com, tushar.n.dave@oracle.com, sowmini.varadhan@oracle.com, mike.kravetz@oracle.com, adam.buchbinder@gmail.com, minchan@kernel.org, hughd@google.com, kirill.shutemov@linux.intel.com, keescook@chromium.org, allen.pais@oracle.com, aryabinin@virtuozzo.com, atish.patra@oracle.com, joe@perches.com, pmladek@suse.com, jslaby@suse.cz, cmetcalf@mellanox.com, paul.gortmaker@windriver.com, jmarchan@redhat.com, lstoakes@gmail.com, 0x7f454c46@gmail.com, vbabka@suse.cz, tglx@linutronix.de, mingo@redhat.com, dan.j.williams@intel.com, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net, vdavydov.dev@gmail.com, hannes@cmpxchg.org, namit@vmware.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, Khalid Aziz Message-ID: <20170106162213.Vr1_z1AE1LAW93s5UUJkHgVJ4r_D5-BEg5Q2zqEC2vw@z> On 01/06/2017 08:36 AM, Dave Hansen wrote: > On 01/06/2017 07:32 AM, Khalid Aziz wrote: >> I agree with you on simplicity first. Subpage granularity is complex, >> but the architecture allows for subpage granularity. Maybe the right >> approach is to support this at page granularity first for swappable >> pages and then expand to subpage granularity in a subsequent patch? >> Pages locked in memory can already use subpage granularity with my patch. > > What do you mean by "locked in memory"? mlock()'d memory can still be > migrated around and still requires "swap" ptes, for instance. You are right. Page migration can invalidate subpage granularity even for locked pages. Is it possible to use cpusets to keep a task and its memory locked on a single node? Just wondering if there are limited cases where subpage granularity could work without supporting subpage granularity for tags in swap. It still sounds like the right thing to do is to get a reliable implementation in place with page size granularity and then add the complexity of subpage granularity. Thanks, Khalid