Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756173AbcDGMKg (ORCPT ); Thu, 7 Apr 2016 08:10:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:42191 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755872AbcDGMKe (ORCPT ); Thu, 7 Apr 2016 08:10:34 -0400 Date: Thu, 7 Apr 2016 14:10:30 +0200 From: Petr Mladek To: Josh Poimboeuf Cc: Jiri Kosina , Jessica Yu , Miroslav Benes , linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Vojtech Pavlik Subject: Re: [RFC PATCH v1.9 00/14] livepatch: hybrid consistency model Message-ID: <20160407121030.GC27670@pathway.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 778 Lines: 20 On Fri 2016-03-25 14:34:47, Josh Poimboeuf wrote: > TODO: > - try ftrace handler switching idea from v1 cover letter I have had a discussion about it with Mirek. This would help with kthreads. If they are sleeping in a patched function, we wake them up, this will help to migrate them before they get asleep again. But it might be quite tricky. We must make sure to avoid a deadlock. We probably should not check the stack in atomic context or in time sensitive functions. An alternative would be to check the stack and try migration when the process goes into a sleep. It is a location where we should not be afraid of any deadlocks or slight delay. There should be high changes for a successful migration with a minimal impact on the system throughput. Best Regards, Petr