From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162743AbeBPSDw (ORCPT ); Fri, 16 Feb 2018 13:03:52 -0500 Received: from mga03.intel.com ([134.134.136.65]:32141 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161111AbeBPSDv (ORCPT ); Fri, 16 Feb 2018 13:03:51 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,520,1511856000"; d="scan'208";a="18718023" Subject: Re: [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL To: Nadav Amit References: <20180215132053.6C9B48C8@viggo.jf.intel.com> <20180215132055.F341C31E@viggo.jf.intel.com> Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, jgross@suse.com, x86@kernel.org From: Dave Hansen Message-ID: Date: Fri, 16 Feb 2018 10:03:50 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/16/2018 09:47 AM, Nadav Amit wrote: >> But, this also means that we now get *no* opportunity to use >> global pages with PTI, even for data which is shared such as the >> cpu_entry_area and entry/exit text. > > Doesn’t this patch change the kernel behavior when the “nopti” > parameter is used? I don't think so. It takes the "nopti" behavior and effectively makes it apply everywhere. So it changes the PTI behavior, not the "nopti" behavior. Maybe it would help to quote the code that you think does this instead of the description. :) 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 B08F26B0007 for ; Fri, 16 Feb 2018 13:03:52 -0500 (EST) Received: by mail-pl0-f72.google.com with SMTP id 4so2680302plb.1 for ; Fri, 16 Feb 2018 10:03:52 -0800 (PST) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id s25si162169pge.187.2018.02.16.10.03.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Feb 2018 10:03:51 -0800 (PST) Subject: Re: [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL References: <20180215132053.6C9B48C8@viggo.jf.intel.com> <20180215132055.F341C31E@viggo.jf.intel.com> From: Dave Hansen Message-ID: Date: Fri, 16 Feb 2018 10:03:50 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Nadav Amit Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, jgross@suse.com, x86@kernel.org On 02/16/2018 09:47 AM, Nadav Amit wrote: >> But, this also means that we now get *no* opportunity to use >> global pages with PTI, even for data which is shared such as the >> cpu_entry_area and entry/exit text. > > Doesna??t this patch change the kernel behavior when the a??noptia?? > parameter is used? I don't think so. It takes the "nopti" behavior and effectively makes it apply everywhere. So it changes the PTI behavior, not the "nopti" behavior. Maybe it would help to quote the code that you think does this instead of the description. :) -- 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