Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754448AbaLBH1c (ORCPT ); Tue, 2 Dec 2014 02:27:32 -0500 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:39530 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752342AbaLBH1R (ORCPT ); Tue, 2 Dec 2014 02:27:17 -0500 From: "Aneesh Kumar K.V" To: Benjamin Herrenschmidt , Mel Gorman Cc: Linux Kernel , Linux-MM , LinuxPPC-dev , Hugh Dickins , Dave Jones , Rik van Riel , Ingo Molnar , Kirill Shutemov , Sasha Levin , Paul Mackerras , Linus Torvalds Subject: Re: [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa In-Reply-To: <1417473762.7182.8.camel@kernel.crashing.org> References: <1416578268-19597-1-git-send-email-mgorman@suse.de> <1416578268-19597-4-git-send-email-mgorman@suse.de> <1417473762.7182.8.camel@kernel.crashing.org> User-Agent: Notmuch/0.19+2~g32855b9 (http://notmuchmail.org) Emacs/25.0.50.1 (x86_64-pc-linux-gnu) Date: Tue, 02 Dec 2014 12:57:00 +0530 Message-ID: <87k32ah5q3.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14120207-0033-0000-0000-0000031B1BB4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Benjamin Herrenschmidt writes: > On Fri, 2014-11-21 at 13:57 +0000, Mel Gorman wrote: >> Convert existing users of pte_numa and friends to the new helper. Note >> that the kernel is broken after this patch is applied until the other >> page table modifiers are also altered. This patch layout is to make >> review easier. > > Aneesh, the removal of the DSISR_PROTFAULT checks, I wonder if we might > break something here ... (I know, I asked for them to be removed :-) > That is the reason I converted that to a WARN_ON in later patch. > IE, we basically bounce all protection checks to the "normal" VMA > protection checking, so far so good... > > But what about the subpage protection stuff ? Will that still work ? > I did look at that before. So if we had subpage access limitted, when we take a fault for that subpage, we bail out early in hash_page_mm. (with rc = 2). low_hash_fault handle that case directly. We will not end up calling do_page_fault. Now, hash_preload can possibly insert an hpte in hash page table even if the access is not allowed by the pte permissions. But i guess even that is ok. because we will fault again, end-up calling hash_page_mm where we handle that part correctly. -aneesh -- 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/