From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 9A56E6B0069 for ; Tue, 2 Dec 2014 02:27:21 -0500 (EST) Received: by mail-pa0-f47.google.com with SMTP id kq14so12791208pab.6 for ; Mon, 01 Dec 2014 23:27:21 -0800 (PST) Received: from e28smtp03.in.ibm.com (e28smtp03.in.ibm.com. [122.248.162.3]) by mx.google.com with ESMTPS id uq12si32377591pab.95.2014.12.01.23.27.17 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 01 Dec 2014 23:27:20 -0800 (PST) Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 2 Dec 2014 12:57:12 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 917B21258054 for ; Tue, 2 Dec 2014 12:57:26 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay05.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sB27RjRZ2556176 for ; Tue, 2 Dec 2014 12:57:46 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sB27R870029494 for ; Tue, 2 Dec 2014 12:57:08 +0530 From: "Aneesh Kumar K.V" 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> 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 Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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