From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754683Ab3K2UfK (ORCPT ); Fri, 29 Nov 2013 15:35:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:22944 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752606Ab3K2UfH (ORCPT ); Fri, 29 Nov 2013 15:35:07 -0500 Date: Fri, 29 Nov 2013 21:35:50 +0100 From: Oleg Nesterov To: "H. Peter Anvin" Cc: Andi Kleen , 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 Message-ID: <20131129203550.GA14723@redhat.com> References: <1385426236-14960-1-git-send-email-andi@firstfloor.org> <20131129183558.GA9803@redhat.com> <20131129195419.GB17656@two.firstfloor.org> <20131129200532.GA13561@redhat.com> <5298F66A.2010600@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5298F66A.2010600@zytor.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/29, H. Peter Anvin wrote: > > 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 Well, it is not really global, it is for mm_cpumask() and for good reason? And is it really worse than on_each_cpu(do_sync_core) and the usage of text_mutex? > (and wouldn't help > shared-memory code segments, if we care about that at all.) Well, I think this should only support the private mappings. > It also > means much bigger code ranges would be affected. Yes, this is true. Oleg.