From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate6.de.ibm.com (8.13.8/8.13.8) with ESMTP id m8OMLSXe507848 for ; Wed, 24 Sep 2008 22:21:28 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m8OMLN0g4034566 for ; Thu, 25 Sep 2008 00:21:27 +0200 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m8OMLN1t018117 for ; Thu, 25 Sep 2008 00:21:23 +0200 Subject: Re: PTE access rules & abstraction From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com In-Reply-To: References: <1221846139.8077.25.camel@pasglop> <48D739B2.1050202@goop.org> <1222117551.12085.39.camel@pasglop> Content-Type: text/plain Date: Thu, 25 Sep 2008 00:17:00 +0200 Message-Id: <1222294620.5968.4.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Benjamin Herrenschmidt , Jeremy Fitzhardinge , Linux Memory Management List , Linux Kernel list , Nick Piggin List-ID: On Wed, 2008-09-24 at 19:45 +0100, Hugh Dickins wrote: > > I know s390 has different issues & constraints. Martin told me during > > Plumbers that mprotect was probably also broken for him. > > Then I hope he will probably send Linus the fix. > > Though what we already have falls somewhat short of perfection, > I've much more enthusiasm for fixing its bugs, than for any fancy > redesign introducing its own bugs. Others have more stamina! As far as I can tell the current code should work. It is not pretty though, in particular the nasty pairing of flush_tlb_mm() with ptep_set_wrprotect() and flush_tlb_range() with change_protection() is fragile. For me the question is if we can find a sensible set of basic primitives that work for all architectures in a performant way. This is really hard.. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org