From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758017AbbDXTYj (ORCPT ); Fri, 24 Apr 2015 15:24:39 -0400 Received: from shelob.surriel.com ([74.92.59.67]:46599 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751270AbbDXTYi (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 2/2] show nohz_full cpus in sysfs Date: Fri, 24 Apr 2015 15:24:28 -0400 Message-Id: <1429903468-11099-3-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 Currently there is no way to query which CPUs are in nohz_full mode from userspace. Export the CPU list running in nohz_full mode in sysfs, specifically in the file /sys/devices/system/cpu/nohz_full This can be used by system management tools like libvirt, openstack, and others to ensure proper task placement. Signed-off-by: Rik van Riel --- drivers/base/cpu.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index ea23ee7b545b..78720e706176 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "base.h" @@ -276,6 +277,19 @@ static ssize_t print_cpus_isolated(struct device *dev, } static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL); +#ifdef CONFIG_NO_HZ_FULL +static ssize_t print_cpus_nohz_full(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(tick_nohz_full_mask)); + + return n; +} +static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL); +#endif + static void cpu_device_release(struct device *dev) { /* @@ -443,6 +457,9 @@ static struct attribute *cpu_root_attrs[] = { &dev_attr_kernel_max.attr, &dev_attr_offline.attr, &dev_attr_isolated.attr, +#ifdef CONFIG_NO_HZ_FULL + &dev_attr_nohz_full.attr, +#endif #ifdef CONFIG_GENERIC_CPU_AUTOPROBE &dev_attr_modalias.attr, #endif -- 2.1.0