From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f51.google.com (mail-oi0-f51.google.com [209.85.218.51]) by kanga.kvack.org (Postfix) with ESMTP id 251566B0074 for ; Thu, 18 Jun 2015 05:40:26 -0400 (EDT) Received: by oiax193 with SMTP id x193so53433382oia.2 for ; Thu, 18 Jun 2015 02:40:25 -0700 (PDT) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [58.251.152.64]) by mx.google.com with ESMTPS id h144si4396131oib.126.2015.06.18.02.40.22 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 18 Jun 2015 02:40:24 -0700 (PDT) Message-ID: <55829149.60807@huawei.com> Date: Thu, 18 Jun 2015 17:37:13 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [RFC PATCH 00/12] mm: mirrored memory support for page buddy allocations References: <55704A7E.5030507@huawei.com> <557FD5F8.10903@suse.cz> <557FDB9B.1090105@huawei.com> <557FF06A.3020000@suse.cz> <55821D85.3070208@huawei.com> <55825DF0.9090903@suse.cz> In-Reply-To: <55825DF0.9090903@suse.cz> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Andrew Morton , nao.horiguchi@gmail.com, Yinghai Lu , "H. Peter Anvin" , Thomas Gleixner , mingo@elte.hu, Xiexiuqi , Hanjun Guo , "Luck, Tony" , Linux MM , LKML On 2015/6/18 13:58, Vlastimil Babka wrote: > On 18.6.2015 3:23, Xishi Qiu wrote: >> On 2015/6/16 17:46, Vlastimil Babka wrote: >> >>> On 06/16/2015 10:17 AM, Xishi Qiu wrote: >>>> On 2015/6/16 15:53, Vlastimil Babka wrote: >>>> >>>>> On 06/04/2015 02:54 PM, Xishi Qiu wrote: >>>>>> >>>>>> I think add a new migratetype is btter and easier than a new zone, so I use >>>>> >>>>> If the mirrored memory is in a single reasonably compact (no large holes) range >>>>> (per NUMA node) and won't dynamically change its size, then zone might be a >>>>> better option. For one thing, it will still allow distinguishing movable and >>>>> unmovable allocations within the mirrored memory. >>>>> >>>>> We had enough fun with MIGRATE_CMA and all kinds of checks it added to allocator >>>>> hot paths, and even CMA is now considering moving to a separate zone. >>>>> >>>> >>>> Hi, how about the problem of this case: >>>> e.g. node 0: 0-4G(dma and dma32) >>>> node 1: 4G-8G(normal), 8-12G(mirror), 12-16G(normal), >>>> so more than one normal zone in a node? or normal zone just span the mirror zone? >>> >>> Normal zone can span the mirror zone just fine. However, it will result in zone >>> scanners such as compaction to skip over the mirror zone inefficiently. Hmm... > > On the other hand, it would skip just as inefficiently over MIGRATE_MIRROR > pageblocks within a Normal zone. Since migrating pages between MIGRATE_MIRROR > and other types pageblocks would violate what the allocations requested. > > Having separate zone instead would allow compaction to run specifically on the > zone and defragment movable allocations there (i.e. userspace pages if/when > userspace requesting mirrored memory is supported). > >>> >> >> Hi Vlastimil, >> >> If there are many mirror regions in one node, then it will be many holes in the >> normal zone, is this fine? > > Yeah, it doesn't matter how many holes there are. So mirror zone and normal zone will span each other, right? e.g. node 1: 4G-8G(normal), 8-12G(mirror), 12-16G(normal), 16-24G(mirror), 24-28G(normal) ... normal: start=4G, size=28-4=24G, mirror: start=8G, size=24-8=16G, I think zone is defined according to the special address range, like 16M(DMA), 4G(DMA32), and is it appropriate to add a new mirror zone with a volatile physical address? Thanks, Xishi Qiu -- 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