From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753590AbbCBJZE (ORCPT ); Mon, 2 Mar 2015 04:25:04 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:56970 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750849AbbCBJZB (ORCPT ); Mon, 2 Mar 2015 04:25:01 -0500 Date: Mon, 2 Mar 2015 10:24:40 +0100 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Mathieu Desnoyers , Andi Kleen , Andi Kleen , x86@kernel.org, linux-kernel@vger.kernel.org, oleg@redhat.com, rusty@rustcorp.com.au, mingo@kernel.org Subject: Re: [RFC][PATCH] module: Optimize __module_address() using a latched RB-tree Message-ID: <20150302092440.GF5029@twins.programming.kicks-ass.net> References: <20150223170436.GC5029@twins.programming.kicks-ass.net> <20150223174340.GD27767@tassilo.jf.intel.com> <20150226114309.GR21418@twins.programming.kicks-ass.net> <2127583772.183982.1424966563927.JavaMail.zimbra@efficios.com> <20150226164356.GU21418@twins.programming.kicks-ass.net> <20150226182817.GY15405@linux.vnet.ibm.com> <20150226191335.GY21418@twins.programming.kicks-ass.net> <20150228164112.GB24151@twins.programming.kicks-ass.net> <20150228165654.GC24151@twins.programming.kicks-ass.net> <20150228233203.GL15405@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150228233203.GL15405@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 28, 2015 at 03:32:03PM -0800, Paul E. McKenney wrote: > Whew! > > Though otherwise whatever you were doing would have been pretty cool > and fun to learn about. ;-) So I think I can do that; where readers and writers are fully separated, but it requires: - tripple latch - copy operator - nested RCU And the result would be horribly expensive (mostly due to the copy operator on dynamic data structures) on the update side, which severely limits the applicability of the scheme.