Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966183AbbD1Uwi (ORCPT ); Tue, 28 Apr 2015 16:52:38 -0400 Received: from mail-la0-f47.google.com ([209.85.215.47]:32872 "EHLO mail-la0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965358AbbD1Uwf (ORCPT ); Tue, 28 Apr 2015 16:52:35 -0400 MIME-Version: 1.0 In-Reply-To: <20150428181203.35812.60474.stgit@dwillia2-desk3.amr.corp.intel.com> References: <20150428181203.35812.60474.stgit@dwillia2-desk3.amr.corp.intel.com> From: Andy Lutomirski Date: Tue, 28 Apr 2015 13:52:13 -0700 Message-ID: Subject: Re: [PATCH v2 00/20] libnd: non-volatile memory device support To: Dan Williams Cc: linux-nvdimm , Boaz Harrosh , Neil Brown , Dave Chinner , "H. Peter Anvin" , Ingo Molnar , "Rafael J. Wysocki" , Robert Moore , Christoph Hellwig , Linux ACPI , Jeff Moyer , Nicholas Moulin , Matthew Wilcox , Ross Zwisler , Vishal Verma , Jens Axboe , Borislav Petkov , Thomas Gleixner , Greg KH , "linux-kernel@vger.kernel.org" , Andrew Morton , Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2211 Lines: 47 On Tue, Apr 28, 2015 at 11:24 AM, Dan Williams wrote: > Changes since v1 [1]: Incorporates feedback received prior to April 24. > > 1/ Ingo said [2]: > > "So why on earth is this whole concept and the naming itself > ('drivers/block/nd/' stands for 'NFIT Defined', apparently) > revolving around a specific 'firmware' mindset and revolving > around specific, weirdly named, overly complicated looking > firmware interfaces that come with their own new weird > glossary??" > > Indeed, we of course consulted the NFIT specification to determine > the shape of the sub-system, but then let its terms and data > structures permeate too deep into the implementation. That is fixed > now with all NFIT specifics factored out into acpi.c. The NFIT is no > longer required reading to review libnd. Only three concepts are > needed: > > i/ PMEM - contiguous memory range where cpu stores are > persistent once they are flushed through the memory > controller. > > ii/ BLK - mmio apertures (sliding windows) that can be > programmed to access an aperture's-worth of persistent > media at a time. > > iii/ DPA - "dimm-physical-address", address space local to a > dimm. A dimm may provide both PMEM-mode and BLK-mode > access to a range of DPA. libnd manages allocation of DPA > to either PMEM or BLK-namespaces to resolve this aliasing. Mostly for my understanding: is there a name for "address relative to the address lines on the DIMM"? That is, a DIMM that exposes 8 GB of apparent physical memory, possibly interleaved, broken up, or weirdly remapped by the memory controller, would still have addresses between 0 and 8 GB. Some of those might be PMEM windows, some might be MMIO, some might be BLK apertures, etc. IIUC "DPA" refers to actual addressable storage, not this type of address? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/