From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Subject: Re: [RFC PATCH]: ACPI: Automatically online hot-added memory Date: Fri, 19 Mar 2010 13:23:33 -0400 Message-ID: <4BA3B315.6080905@redhat.com> References: <20100309141203.10037.62453.sendpatchset@prarit.bos.redhat.com> <201003121418.14204.trenn@suse.de> <4BA123DB.5050807@redhat.com> <201003191755.35421.trenn@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45163 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716Ab0CSRXk (ORCPT ); Fri, 19 Mar 2010 13:23:40 -0400 In-Reply-To: <201003191755.35421.trenn@suse.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Thomas Renninger Cc: ykzhao , chen gong , Matthew Garrett , "linux-acpi@vger.kernel.org" > > Blocking does not work. > But I have an idea, whatabout: > - CPU add rule which only adds a CPU if the corresponding Numa node already > has onlined memory > - Memory add rule which adds the memory and also onlines CPUs if the Numa > node still has offlined CPUs > > This has the side effect that you online a CPU which may have been offlined on > purpose if you hotadd memory on the same node..., a rather uncommon case. > > That actually might be more of a problem than you think. It's not atypical that in the evening a system's components are offlined in order to save power. Maintenance also is scheduled for downtime so when memory is added to the system we may bring cpus into service erroneously. I think the "end-user" may not be too happy with this result. [OTOH, a little documentation could fix that issue] > A quick try showed that it would be convenient to add the Numa node to the > uevent which is a bit tricky... > Ok, I got this working, but messed up the cpu hotplugging with my patches: > ... > Unable to map lapic 32 to logical cpu number > ... > This already worked... > > I wanted to post something today, but I couldn't made it. > Still I more or less could prove that above works and I hopefully can show > some results on Monday. > > If it works then I'm all for it :) > Comments? > > Thomas > > BTW: I was wrong with slub. It also has bad side effects. What is strange is > FWIW, I'm testing with slab. P.