From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751894AbbLHSaA (ORCPT ); Tue, 8 Dec 2015 13:30:00 -0500 Received: from www.linutronix.de ([62.245.132.108]:51641 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152AbbLHS37 (ORCPT ); Tue, 8 Dec 2015 13:29:59 -0500 Date: Tue, 8 Dec 2015 19:29:10 +0100 (CET) From: Thomas Gleixner To: Dave Hansen cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, dave.hansen@linux.intel.com Subject: Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy In-Reply-To: <56671C15.10304@sr71.net> Message-ID: References: <20151204011424.8A36E365@viggo.jf.intel.com> <20151204011438.E50D1498@viggo.jf.intel.com> <566706A1.3040906@sr71.net> <56671C15.10304@sr71.net> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 8 Dec 2015, Dave Hansen wrote: > Here's how it looks with the suggested modifications. > > Whatever compiler wonkiness I was seeing is gone now, so I've used the > most straightforward version of the shifts. > + * gcc generates better code if we do this rather than: > + * pkey = (flags & mask) >> shift > + */ > + pkey = (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT; ROTFL! From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com [74.125.82.52]) by kanga.kvack.org (Postfix) with ESMTP id EBE6E6B0257 for ; Tue, 8 Dec 2015 13:30:00 -0500 (EST) Received: by wmec201 with SMTP id c201so41257422wme.1 for ; Tue, 08 Dec 2015 10:30:00 -0800 (PST) Received: from Galois.linutronix.de (linutronix.de. [2001:470:1f0b:db:abcd:42:0:1]) by mx.google.com with ESMTPS id z8si32055532wmg.102.2015.12.08.10.29.59 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 08 Dec 2015 10:30:00 -0800 (PST) Date: Tue, 8 Dec 2015 19:29:10 +0100 (CET) From: Thomas Gleixner Subject: Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy In-Reply-To: <56671C15.10304@sr71.net> Message-ID: References: <20151204011424.8A36E365@viggo.jf.intel.com> <20151204011438.E50D1498@viggo.jf.intel.com> <566706A1.3040906@sr71.net> <56671C15.10304@sr71.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, dave.hansen@linux.intel.com On Tue, 8 Dec 2015, Dave Hansen wrote: > Here's how it looks with the suggested modifications. > > Whatever compiler wonkiness I was seeing is gone now, so I've used the > most straightforward version of the shifts. > + * gcc generates better code if we do this rather than: > + * pkey = (flags & mask) >> shift > + */ > + pkey = (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT; ROTFL! -- 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