From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by kanga.kvack.org (Postfix) with ESMTP id 995C46B0074 for ; Thu, 18 Jun 2015 05:55:47 -0400 (EDT) Received: by wibdq8 with SMTP id dq8so81402314wib.1 for ; Thu, 18 Jun 2015 02:55:47 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id h5si14379243wiy.49.2015.06.18.02.55.45 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 18 Jun 2015 02:55:46 -0700 (PDT) Message-ID: <5582959E.4080402@suse.cz> Date: Thu, 18 Jun 2015 11:55:42 +0200 From: Vlastimil Babka 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> <55829149.60807@huawei.com> In-Reply-To: <55829149.60807@huawei.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu 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 06/18/2015 11:37 AM, Xishi Qiu wrote: > 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 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, Yes, that works. It's somewhat unfortunate wrt performance that the hardware does it like this though. > I think zone is defined according to the special address range, like 16M(DMA), 4G(DMA32), Traditionally yes. But then there is ZONE_MOVABLE, this year's LSF/MM we discussed (and didn't outright deny) ZONE_CMA... I'm not saying others will favour the new zone approach though, it's just my opinion that it might be a better option than a new migratetype. > and is it appropriate to add a new mirror zone with a volatile physical address? By "volatile" you mean what, that the example above would change dynamically? That would be rather challenging... > 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