Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031411AbbDXUjZ (ORCPT ); Fri, 24 Apr 2015 16:39:25 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:33325 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030318AbbDXUjY (ORCPT ); Fri, 24 Apr 2015 16:39:24 -0400 MIME-Version: 1.0 In-Reply-To: <20150424124905.07e29a3b1392513144cd1568@linux-foundation.org> References: <1429825201-2825-1-git-send-email-hagen@jauu.net> <20150424124905.07e29a3b1392513144cd1568@linux-foundation.org> Date: Fri, 24 Apr 2015 22:39:23 +0200 Message-ID: Subject: Re: [PATCH] enforce function inlining for hot functions From: Hagen Paul Pfeifer To: Andrew Morton Cc: "linux-kernel@vger.kernel.org" , Ingo Molnar , "H. Peter Anvin" , "David S. Miller" , "Paul E. McKenney" , x86@kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1386 Lines: 29 On 24 April 2015 at 21:49, Andrew Morton wrote: > I can't reproduce this with either gcc-4.8.2 or gcc-4.4.4. The patch > makes zero difference to `size vmlinux' and a bit of poking around with > nm doesn't show any out-of-lined versions of the functions you > identify. > > So. More details, please. How to demonstrate this, gcc versions, etc. Hey Andrew, first of all you should probably scan over https://lkml.org/lkml/2015/4/21/178 Some questions are already answered there. Here is the situation: the inlining problem occur with the 4.9.x branch - I tried to reproduce it with 4.8.x and saw *no* problems. So it is probably limited to 4.9 - which is sad. I don't checked it with 5.0 or 5.1 yet. Then, if CONFIG_OPTIMIZE_INLINING is disabled inlining is enforced anyway, so there is no problem because all inlined marked functions are always inlined - gcc heuristic is defacto disabled. This patch makes sure that the hot functions always inlined, no matter what config is selected or compiler version is used. Yes, in an ideal world gcc had inlined most of them - now we enforce the ideal world. Hagen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/