Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755372AbaFYM4W (ORCPT ); Wed, 25 Jun 2014 08:56:22 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:50506 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752638AbaFYM4V (ORCPT ); Wed, 25 Jun 2014 08:56:21 -0400 Date: Wed, 25 Jun 2014 13:54:21 +0100 From: One Thousand Gnomes To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, tj@kernel.org, rostedt@goodmis.org, mingo@redhat.com, akpm@linux-foundation.org, andi@firstfloor.org, paulmck@linux.vnet.ibm.com, pavel@ucw.cz, jirislaby@gmail.com, Vojtech Pavlik , Michael Matz , Jiri Kosina Subject: Re: [PATCH 00/21] kGraft Message-ID: <20140625135421.67cd5f5f@alan.etchedpixels.co.uk> In-Reply-To: <1403694329-3064-1-git-send-email-jslaby@suse.cz> References: <1403694329-3064-1-git-send-email-jslaby@suse.cz> Organization: Intel Corporation X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Jun 2014 13:05:29 +0200 Jiri Slaby wrote: > Hi, > > this is a repost of the second round of RFC on kGraft, the linux > kernel online patching developed at SUSE. This repost only widened the > target audience for broader review, no code change happened. - wait_event_freezable(khubd_wait, + wait_event_freezable(khubd_wait, ({ kgr_task_safe(current); The changes are somewhat ugly with all the kgraft crap leaking into plces like jbd and freezer and usb. That says to me its not well isolated and there must be a better way of hiding that kgr stuff so we don't have to kepe putting more code into all the kthreads, and inevitably missing them or have people getting it wrong. You also wake up all the kthreads when some of them might not expect to be woken and may not check for the case of a bogus wake. You add instructions to various hotpaths (despite the CONFIG comment). Have you done timing analysis of their impact when turned on ? Can you explain a bit more about why the path you've chosen was used as opposed to using the power management freeze/resume path. Would that not be a lot less intrusive ? Don't get me wrong - I'd like a good working ksplice/graft ! Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/