From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753008AbaKJVrF (ORCPT ); Mon, 10 Nov 2014 16:47:05 -0500 Received: from mail-yh0-f50.google.com ([209.85.213.50]:64513 "EHLO mail-yh0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751644AbaKJVrD (ORCPT ); Mon, 10 Nov 2014 16:47:03 -0500 MIME-Version: 1.0 In-Reply-To: References: <1415644096-3513-1-git-send-email-j.glisse@gmail.com> <1415644096-3513-4-git-send-email-j.glisse@gmail.com> <20141110205814.GA4186@gmail.com> Date: Mon, 10 Nov 2014 13:47:01 -0800 X-Google-Sender-Auth: kemoX7yYDk0nsm029CUbjQK5HiI Message-ID: Subject: Re: [PATCH 3/5] lib: lockless generic and arch independent page table (gpt) v2. From: Linus Torvalds To: Jerome Glisse Cc: Andrew Morton , Linux Kernel Mailing List , linux-mm , Joerg Roedel , Mel Gorman , "H. Peter Anvin" , Peter Zijlstra , Andrea Arcangeli , Johannes Weiner , Larry Woodman , Rik van Riel , Dave Airlie , Brendan Conoboy , Joe Donohue , Duncan Poole , Sherry Cheung , Subhash Gutti , John Hubbard , Mark Hairgrove , Lucien Dunning , Cameron Buschardt , Arvind Gopalakrishnan , Shachar Raindel , Liran Liss , Roland Dreier , Ben Sander , Greg Stoner , John Bridgman , Michael Mantor , Paul Blinzer , Laurent Morichetti , Alexander Deucher , Oded Gabbay , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 10, 2014 at 1:35 PM, Linus Torvalds wrote: > > Or do you actually have a setup where actual non-CPU hardware actually > walks the page tables you create and call "page tables"? So just to clarify: I haven't looked at all your follow-up patches at all, although I've seen the overviews in earlier versions. When trying to read through the latest version, I got stuck on this one, and felt it was crazy. But maybe I'm misreading it and it actually has good reasons for it. But just from the details I look at, some of it looks too incestuous with the system (the split PTL lock use), other parts look really really odd (like the 64-bit shift counts), and some of it looks just plain buggy (the bitops for synchronization). And none of it is all that easy to actually read. Linus