From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id D86226B0038 for ; Thu, 11 May 2017 04:51:23 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id 44so4478087wry.5 for ; Thu, 11 May 2017 01:51:23 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id m12si7059327wmi.75.2017.05.11.01.51.21 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 11 May 2017 01:51:22 -0700 (PDT) Subject: Re: [PATCH v7 0/7] Introduce ZONE_CMA References: <20170411181519.GC21171@dhcp22.suse.cz> <20170412013503.GA8448@js1304-desktop> <20170413115615.GB11795@dhcp22.suse.cz> <20170417020210.GA1351@js1304-desktop> <20170424130936.GB1746@dhcp22.suse.cz> <20170425034255.GB32583@js1304-desktop> <20170427150636.GM4706@dhcp22.suse.cz> <32ac1107-14a3-fdff-ad48-0e246fec704f@suse.cz> <20170502130326.GJ14593@dhcp22.suse.cz> <398b341c-5fa7-1ad7-0840-752fa1908921@suse.cz> <20170504124648.GG31540@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: <203a7f52-d444-dbcc-0cc0-0c77dffbcadd@suse.cz> Date: Thu, 11 May 2017 10:51:17 +0200 MIME-Version: 1.0 In-Reply-To: <20170504124648.GG31540@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Joonsoo Kim , Andrew Morton , Rik van Riel , Johannes Weiner , mgorman@techsingularity.net, Laura Abbott , Minchan Kim , Marek Szyprowski , Michal Nazarewicz , "Aneesh Kumar K . V" , Russell King , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@lge.com, Heiko Carstens , Martin Schwidefsky On 05/04/2017 02:46 PM, Michal Hocko wrote: > On Thu 04-05-17 14:33:24, Vlastimil Babka wrote: >>> >>> I am pretty sure s390 and ppc support NUMA and aim at supporting really >>> large systems. >> >> I don't see ppc there, > > config KVM_BOOK3S_64_HV > tristate "KVM for POWER7 and later using hypervisor mode in host" > depends on KVM_BOOK3S_64 && PPC_POWERNV > select KVM_BOOK3S_HV_POSSIBLE > select MMU_NOTIFIER > select CMA > > fa61a4e376d21 tries to explain some more Uh, that's unfortunate then. > [...] >>> Are we really ready to add another thing like that? How are distribution >>> kernels going to handle that? >> >> I still hope that generic enterprise/desktop distributions can disable >> it, and it's only used for small devices with custom kernels. >> >> The config burden is already there in any case, it just translates to >> extra migratetype and fastpath hooks, not extra zone and potentially >> less nodes. > > AFAIU the extra migrate type costs nothing when there are no cma > reservations. And those hooks can be made noop behind static branch > as well. So distribution kernels do not really have to be afraid of > enabling CMA currently. The tradeoff is unfortunate :/ -- 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