From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id F37ED6B0331 for ; Wed, 7 Feb 2018 11:25:21 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id 30so807934wrw.6 for ; Wed, 07 Feb 2018 08:25:21 -0800 (PST) Received: from merlin.infradead.org (merlin.infradead.org. [2001:8b0:10b:1231::1]) by mx.google.com with ESMTPS id 91si1452089wrn.294.2018.02.07.08.25.20 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 07 Feb 2018 08:25:20 -0800 (PST) Date: Wed, 7 Feb 2018 17:25:07 +0100 From: Peter Zijlstra Subject: Re: [RFC 0/3] x86: Patchable constants Message-ID: <20180207162507.GB25219@hirez.programming.kicks-ass.net> References: <20180207145913.2703-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180207145913.2703-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Linus Torvalds , x86@kernel.org, Tom Lendacky , Dave Hansen , Andy Lutomirski , Borislav Petkov , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Feb 07, 2018 at 05:59:10PM +0300, Kirill A. Shutemov wrote: > This conversion makes GCC generate worse code. Conversion __PHYSICAL_MASK > to a patchable constant adds about 5k in .text on defconfig and makes it > slightly slower at runtime (~0.2% on my box). Do you have explicit examples for the worse code? That might give clue on how to improve things. -- 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