From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752838AbeE1Aq3 (ORCPT ); Sun, 27 May 2018 20:46:29 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44598 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752721AbeE1AqZ (ORCPT ); Sun, 27 May 2018 20:46:25 -0400 From: Stewart Smith To: Michael Ellerman , Akshay Adiga , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: npiggin@gmail.com, ego@linux.vnet.ibm.com, Akshay Adiga Subject: Re: [PATCH] cpuidle/powernv : init all present cpus for deep states In-Reply-To: <87fu2gqa9o.fsf@concordia.ellerman.id.au> References: <1526472134-23757-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> <87fu2gqa9o.fsf@concordia.ellerman.id.au> Date: Mon, 28 May 2018 10:46:11 +1000 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 18052800-0056-0000-0000-000004578E4D X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009093; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000262; SDB=6.01038644; UDB=6.00530875; IPR=6.00817772; MB=3.00021329; MTD=3.00000008; XFM=3.00000015; UTC=2018-05-28 00:46:22 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18052800-0057-0000-0000-0000089BB016 Message-Id: <87k1ror4j0.fsf@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-27_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805280008 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michael Ellerman writes: > Akshay Adiga writes: > >> Init all present cpus for deep states instead of "all possible" cpus. >> Init fails if the possible cpu is gaurded. Resulting in making only >> non-deep states available for cpuidle/hotplug. > > This is basically the opposite of what we just did for IMC. > > There we switched from present to possible, to make it work when some > CPUs are guarded. > > Which makes me think we need a better way of dealing with guarded CPUs, > because working out which code should use present or possible seems to > be basically trial-and-error. > > I'm not actually sure why Guarded CPUs are showing up as possible but > not present, did we do that on purpose or is it just happening by > accident? My guess is that it flows through from firmware putting the guarded out CPUs in the device tree with a not "okay" status (which, I just realised, we're putting something in 'status' that isn't what the current DeviceTree spec says we should... gah - https://github.com/open-power/skiboot/issues/178 filed for that one). The idea behind that is that you can answer "where did all my CPUs go?" by looking at the device tree rather than having to know the platform specific way of how guards are stored. -- Stewart Smith OPAL Architect, IBM.