From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f69.google.com (mail-pa0-f69.google.com [209.85.220.69]) by kanga.kvack.org (Postfix) with ESMTP id 0333E6B0270 for ; Tue, 25 Oct 2016 11:47:08 -0400 (EDT) Received: by mail-pa0-f69.google.com with SMTP id fn5so2748042pab.3 for ; Tue, 25 Oct 2016 08:47:07 -0700 (PDT) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id 19si21302046pgc.314.2016.10.25.08.47.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 25 Oct 2016 08:47:07 -0700 (PDT) Subject: Re: [RFC 1/8] mm: Define coherent device memory node References: <1477283517-2504-1-git-send-email-khandual@linux.vnet.ibm.com> <1477283517-2504-2-git-send-email-khandual@linux.vnet.ibm.com> <580E4043.4090200@intel.com> <580EB3CB.5080200@linux.vnet.ibm.com> From: Dave Hansen Message-ID: <580F7E75.8080600@intel.com> Date: Tue, 25 Oct 2016 08:47:01 -0700 MIME-Version: 1.0 In-Reply-To: <580EB3CB.5080200@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: mhocko@suse.com, js1304@gmail.com, vbabka@suse.cz, mgorman@suse.de, minchan@kernel.org, akpm@linux-foundation.org, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com On 10/24/2016 06:22 PM, Anshuman Khandual wrote: > On 10/24/2016 10:39 PM, Dave Hansen wrote: >>> +#ifdef CONFIG_COHERENT_DEVICE >>>> +#define node_cdm(nid) (NODE_DATA(nid)->coherent_device) >>>> +#define set_cdm_isolation(nid) (node_cdm(nid) = 1) >>>> +#define clr_cdm_isolation(nid) (node_cdm(nid) = 0) >>>> +#define isolated_cdm_node(nid) (node_cdm(nid) == 1) >>>> +#else >>>> +#define set_cdm_isolation(nid) () >>>> +#define clr_cdm_isolation(nid) () >>>> +#define isolated_cdm_node(nid) (0) >>>> +#endif >> FWIW, I think adding all this "cdm" gunk in the names is probably a bad >> thing. >> >> I can think of other memory types that are coherent, but >> non-device-based that might want behavior like this. > > Hmm, I was not aware about non-device-based coherent memory. Could you > please name some of them ? If thats the case we need to change CDM to > some thing which can accommodate both device and non device based > coherent memory. May be like "Differentiated/special coherent memory". > But it needs to communicate that its not system RAM. Thats the idea. Intel has some stuff called MCDRAM. It's described in detail here: > https://software.intel.com/en-us/articles/mcdram-high-bandwidth-memory-on-knights-landing-analysis-methods-tools You can also Google around for more information. I believe Samsung has a technology called High Bandwidth Memory (HBM) that's already a couple of generations old that sounds similar. -- 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