From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Subject: Re: [RFC PATCH]: ACPI: Automatically online hot-added memory Date: Wed, 17 Mar 2010 14:47:55 -0400 Message-ID: <4BA123DB.5050807@redhat.com> References: <20100309141203.10037.62453.sendpatchset@prarit.bos.redhat.com> <1268294876.3632.5.camel@localhost.localdomain> <4B98AA89.4060609@linux.intel.com> <201003121418.14204.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]:42179 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755496Ab0CQSsB (ORCPT ); Wed, 17 Mar 2010 14:48:01 -0400 In-Reply-To: <201003121418.14204.trenn@suse.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Thomas Renninger Cc: chen gong , ykzhao , Matthew Garrett , "linux-acpi@vger.kernel.org" , trenn@novell.com Thomas Renninger wrote: > On Thursday 11 March 2010 09:32:09 chen gong wrote: > >> On 2010-3-11 16:07, ykzhao wrote: >> > ... > >> BTW, how about using UDEV rules to do this operation. It looks more smooth. I know some >> Novell guy is working on it. >> > I also know this guy :) > > These would be the udev rules to automatically add memory/cpus: > SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}="1", RUN+="/bin/logger onlining cpu: $env{DEVPATH}" > SUBSYSTEM=="memory", ACTION=="add", TEST=="state", ATTR{state}=="offline", ATTR{state}="online", RUN+="/bin/logger onlining memory: $env{DEVPATH}" > > But this should be the same as you suggest (at least the memory rule) > to do in the kernel: > automatically online the memory, once hotadded. > > I would not add any udev rules before this does not work > reliably and currently it is totally broken, mainly because: > - not being able to alloc memory on foreign nodes (at least with slab) > - C-state, throttling and cpufreq set up is done without valid > cpu_data(new_cpu) resulting in wrong C-state (and other) info > > Thomas, forgive my ignorance of udev rules ... but can one udev rule block another? ... That's not the best way to explain it ... here's an example: CPU hot add on Nehalem-EX. Memory is brought online. Memory udev events are generated. CPU udev events are generated. Can the memory udev events block the cpu udev events? ie) can I be assured that memory will come online before the cpus? P. > Thomas > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >