From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id 800426B0006 for ; Thu, 15 Mar 2018 11:55:40 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id z11-v6so3424801plo.21 for ; Thu, 15 Mar 2018 08:55:40 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTPS id i2si3663448pgf.145.2018.03.15.08.55.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 15 Mar 2018 08:55:39 -0700 (PDT) Subject: Re: [PATCH v3] x86: treat pkey-0 special References: <1521061214-22385-1-git-send-email-linuxram@us.ibm.com> From: Dave Hansen Message-ID: Date: Thu, 15 Mar 2018 08:55:31 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner , Ram Pai Cc: mingo@redhat.com, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de, fweimer@redhat.com, msuchanek@suse.com, Ulrich.Weigand@de.ibm.com On 03/15/2018 02:46 AM, Thomas Gleixner wrote: >> + if (!pkey || !mm_pkey_is_allocated(mm, pkey)) > Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true > ever. If it does, then this wants to be fixed. I was thinking that we _do_ actually want it to seem allocated. It just get "allocated" implicitly when an mm is created. I think that will simplify the code if we avoid treating it specially in as many places as possible.