From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754174Ab3K2USc (ORCPT ); Fri, 29 Nov 2013 15:18:32 -0500 Received: from terminus.zytor.com ([198.137.202.10]:53069 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933Ab3K2USb (ORCPT ); Fri, 29 Nov 2013 15:18:31 -0500 Message-ID: <5298F66A.2010600@zytor.com> Date: Fri, 29 Nov 2013 12:17:46 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Oleg Nesterov , Andi Kleen CC: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, x86@kernel.org, Andi Kleen , Ingo Molnar , Borislav Petkov Subject: Re: [PATCH] Add a text_poke syscall v2 References: <1385426236-14960-1-git-send-email-andi@firstfloor.org> <20131129183558.GA9803@redhat.com> <20131129195419.GB17656@two.firstfloor.org> <20131129200532.GA13561@redhat.com> In-Reply-To: <20131129200532.GA13561@redhat.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/29/2013 12:05 PM, Oleg Nesterov wrote: > > Can't we invalidate pte (so that any user will stuck in page fault), > update the page(s), restore the pte and drop the locks? > That would require a global TLB shootdown (and wouldn't help shared-memory code segments, if we care about that at all.) It also means much bigger code ranges would be affected. The performance requirements are part of what makes the INT3 solution attractive, but anything is going to inherently be slow. > This way sys_text_poke() won't be x86-specific, and it will be per-mm. That is definitely an appeal. -hpa