Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757858AbaKTTyJ (ORCPT ); Thu, 20 Nov 2014 14:54:09 -0500 Received: from mail-qa0-f46.google.com ([209.85.216.46]:50893 "EHLO mail-qa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbaKTTyH (ORCPT ); Thu, 20 Nov 2014 14:54:07 -0500 MIME-Version: 1.0 In-Reply-To: <1416478790-27522-3-git-send-email-mgorman@suse.de> References: <1416478790-27522-1-git-send-email-mgorman@suse.de> <1416478790-27522-3-git-send-email-mgorman@suse.de> Date: Thu, 20 Nov 2014 11:54:06 -0800 X-Google-Sender-Auth: nSHvSs04_oyxov732_5jCdXsEhs Message-ID: Subject: Re: [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing From: Linus Torvalds To: Mel Gorman Cc: Linux Kernel , Linux-MM , LinuxPPC-dev , Aneesh Kumar , Hugh Dickins , Dave Jones , Rik van Riel , Ingo Molnar , Kirill Shutemov , Sasha Levin , Benjamin Herrenschmidt , Paul Mackerras Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 20, 2014 at 2:19 AM, Mel Gorman wrote: > This is a preparatory patch that introduces protnone helpers for automatic > NUMA balancing. Oh, I hadn't noticed that you had renamed these things. It was probably already true in your V1 version. I do *not* think that "pte_protnone_numa()" makes sense as a name. It only confuses people to think that there is still/again something NUMA-special about the PTE. The whole point of the protnone changes was to make it really very very clear that from a hardware standpoint, this is *exactly* about protnone, and nothing else. The fact that we then use protnone PTE's for numa faults is a VM internal issue, it should *not* show up in the architecture page table helpers. I'm not NAK'ing this name, but I really think it's a very important part of the whole patch series - to stop the stupid confusion about NUMA entries. As far as the page tables are concerned, this has absolutely _zero_ to do with NUMA. We made that mistake once. We're fixing it. Let the naming *show* that it's fixed, and this is "pte_protnone()". The places that use this for NUMA handling might have a comment or something. But they'll be in the VM where this matters, not in the architecture page table description files. The comment would be something like "if the vma is accessible, but the PTE is marked protnone, this is a autonuma entry". Linus -- 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/