On Fri, Apr 24, 2015 at 03:24:27PM -0400, r...@redhat.com wrote:
> From: Rik van Riel <r...@redhat.com>
>
> 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 <lize...@huawei.com>
> Signed-off-by: Rik van Riel <r...@redhat.com>
This patch should go through Peterz.
> ---
> 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
>
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