From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755381AbbJUQGn (ORCPT ); Wed, 21 Oct 2015 12:06:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54201 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732AbbJUQGl (ORCPT ); Wed, 21 Oct 2015 12:06:41 -0400 From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: trenn@suse.de, Prarit Bhargava Subject: [PATCH 0/2] Add CONFIG_PERMANENT_CPU_TOPOLOGY [v2] Date: Wed, 21 Oct 2015 12:06:36 -0400 Message-Id: <1445443598-21036-1-git-send-email-prarit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The information in /sys/devices/system/cpu/cpuX/topology directory is useful for userspace monitoring applications and in-tree utilities like cpupower & turbostat. When down'ing a CPU the /sys/devices/system/cpu/cpuX/topology directory is removed during the CPU_DEAD hotplug callback in the kernel. The problem with this model is that the CPU has not been physically removed and the data in the topology directory is still valid. This patchset adds CONFIG_PERMANENT_CPU_TOPOLOGY, and is Y by default for x86, an N for all other arches. When enabled the kernel is modified so that the topology directory is added to the core cpu sysfs files so that the topology directory exists for the lifetime of the CPU. When disabled, the behavior of the current kernel is maintained (that is, the topology directory is removed on a down and added on an up). Adding CONFIG_PERMANENT_CPU_TOPOLOGY may require additional architecture so that the cpumask data the CPU's topology is not cleared during a CPU down. This patchset combines drivers/base/topology.c and drivers/base/cpu.c to implement CONFIG_PERMANENT_CPU_TOPOLOGY, and leaves all arches except x86 with the current behavior, and adds an additional minor cleanup to drivers/base/cpu.c. [v2]: core_siblings, and thread_siblings are "numa siblings that are online" and "thread siblings that are online" and are used as such within the kernel. They must be zero'd out when the CPU is offline. Prarit Bhargava (2): cpu hotplug, add CONFIG_PERMANENT_CPU_TOPOLOGY and keep topology directory for lifetime of CPU [v2] base, cpu, remove hotplugable_cpu_attr_groups arch/x86/kernel/smpboot.c | 3 - drivers/base/Kconfig | 13 ++++ drivers/base/Makefile | 2 +- drivers/base/cpu.c | 141 ++++++++++++++++++++++++++++++++++++++--- drivers/base/topology.c | 155 --------------------------------------------- 5 files changed, 146 insertions(+), 168 deletions(-) delete mode 100644 drivers/base/topology.c -- 1.7.9.3