Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966119Ab0GPT2y (ORCPT ); Fri, 16 Jul 2010 15:28:54 -0400 Received: from one.firstfloor.org ([213.235.205.2]:34877 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751248Ab0GPT2x (ORCPT ); Fri, 16 Jul 2010 15:28:53 -0400 Date: Fri, 16 Jul 2010 21:28:47 +0200 From: Andi Kleen To: "H. Peter Anvin" Cc: Avi Kivity , Mathieu Desnoyers , LKML , Linus Torvalds , Andrew Morton , Ingo Molnar , Peter Zijlstra , Steven Rostedt , Steven Rostedt , Frederic Weisbecker , Thomas Gleixner , Christoph Hellwig , Li Zefan , Lai Jiangshan , Johannes Berg , Masami Hiramatsu , Arnaldo Carvalho de Melo , Tom Zanussi , KOSAKI Motohiro , Andi Kleen , akpm@osdl.org, Jeremy Fitzhardinge , "Frank Ch. Eigler" Subject: Re: [patch 2/2] x86 NMI-safe INT3 and Page Fault Message-ID: <20100716192847.GC7338@basil.fritz.box> References: <20100714154923.947138065@efficios.com> <20100714155804.252253097@efficios.com> <4C405078.20707@redhat.com> <20100716144927.GA22516@Krystal> <4C408D0C.5050709@redhat.com> <20100716165855.GA3836@Krystal> <4C409CBA.1050709@redhat.com> <4C409F62.6030303@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C409F62.6030303@zytor.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1041 Lines: 27 > Actually, module loading is already a performance problem; a lot of > distros load sometimes hundreds of modules on startup, and it's heavily On startup you don't have many processes. If there's a problem it's surely not the fault of vmalloc_sync_all() BTW in my experience one reason module loading was traditionally slow was that it did a stop_machine(). I think(?) that has been fixed at some point. But even with that's it's more an issue on larger systems. > I really hope noone ever gets the idea of touching user space from an > NMI handler, though, and expecting it to work... It can make sense for a backtrace in a profiler. In fact perf is nearly doing it I believe, but moves it to the self IPI handler in most cases. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/