From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758455AbbDXTYp (ORCPT ); Fri, 24 Apr 2015 15:24:45 -0400 Received: from shelob.surriel.com ([74.92.59.67]:46602 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756096AbbDXTYi (ORCPT ); Fri, 24 Apr 2015 15:24:38 -0400 From: riel@redhat.com To: linux-kernel@vger.kernel.org Cc: tj@kernel.org, umgwanakikbuti@gmail.com, lizefan@huawei.com, fweisbec@gmail.com, gregkh@linuxfoundation.org Subject: [PATCH 1/2] show isolated cpus in sysfs Date: Fri, 24 Apr 2015 15:24:27 -0400 Message-Id: <1429903468-11099-2-git-send-email-riel@redhat.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1429903468-11099-1-git-send-email-riel@redhat.com> References: <1429903468-11099-1-git-send-email-riel@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rik van Riel After system bootup, there is no totally reliable way to see which CPUs are isolated, because the kernel may modify the CPUs specified on the isolcpus= kernel command line option. Export the CPU list that actually got isolated in sysfs, specifically in the file /sys/devices/system/cpu/isolated This can be used by system management tools like libvirt, openstack, and others to ensure proper placement of tasks. Suggested-by: Li Zefan Signed-off-by: Rik van Riel --- drivers/base/cpu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index f160ea44a86d..ea23ee7b545b 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -265,6 +265,17 @@ static ssize_t print_cpus_offline(struct device *dev, } static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); +static ssize_t print_cpus_isolated(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int n = 0, len = PAGE_SIZE-2; + + n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(cpu_isolated_map)); + + return n; +} +static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL); + static void cpu_device_release(struct device *dev) { /* @@ -431,6 +442,7 @@ static struct attribute *cpu_root_attrs[] = { &cpu_attrs[2].attr.attr, &dev_attr_kernel_max.attr, &dev_attr_offline.attr, + &dev_attr_isolated.attr, #ifdef CONFIG_GENERIC_CPU_AUTOPROBE &dev_attr_modalias.attr, #endif -- 2.1.0