Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753945Ab0AHTkH (ORCPT ); Fri, 8 Jan 2010 14:40:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753807Ab0AHTkG (ORCPT ); Fri, 8 Jan 2010 14:40:06 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33849 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752709Ab0AHTkE (ORCPT ); Fri, 8 Jan 2010 14:40:04 -0500 Date: Fri, 8 Jan 2010 11:39:31 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Andi Kleen cc: Christoph Lameter , Peter Zijlstra , KAMEZAWA Hiroyuki , Minchan Kim , "Paul E. McKenney" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "hugh.dickins" , Nick Piggin , Ingo Molnar Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() In-Reply-To: <20100108192815.GB14141@basil.fritz.box> Message-ID: References: <20100106115233.5621bd5e.kamezawa.hiroyu@jp.fujitsu.com> <20100106125625.b02c1b3a.kamezawa.hiroyu@jp.fujitsu.com> <1262969610.4244.36.camel@laptop> <87my0omo3n.fsf@basil.nowhere.org> <20100108192815.GB14141@basil.fritz.box> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 967 Lines: 26 On Fri, 8 Jan 2010, Andi Kleen wrote: > > With 24 CPU threads cheating is very difficult too. Stop making value judgements in you word choice, like "cheating". The fact is, the mmap_sem is per-mm, and works perfectly well. Other locking can be vma-specific, but as already mentioned, it's not going to _help_, since most of the time even hugely threaded programs will be using malloc-like functionality and you have allocations not only cross threads, but in general using the same vma. Another fact is simply that you shouldn't write your app so that it needs to do millions of page faults per second. So this whole "cheating" argument of yours is total bullshit. It bears no relation to reality. Linus -- 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/