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SubjectRe: [PATCH] drivers: base: update cpu offline info when do hotplug
On Tue, Oct 21, 2014 at 9:02 AM, Dan Streetman <ddstreet@ieee.org> wrote:
> On Sun, Oct 19, 2014 at 11:29 PM, Neil Zhang <zhangwm@marvell.com> wrote:
>> The current per-cpu offline info won't be updated if it is
>> hotplugged in/out by a kernel governer.
>> Let's update it via cpu notifier.
>>
>> Signed-off-by: Neil Zhang <zhangwm@marvell.com>
>> ---
>> drivers/base/cpu.c | 25 +++++++++++++++++++++++++
>> 1 file changed, 25 insertions(+)
>>
>> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
>> index 006b1bc..9d61824 100644
>> --- a/drivers/base/cpu.c
>> +++ b/drivers/base/cpu.c
>> @@ -418,10 +418,35 @@ static void __init cpu_dev_register_generic(void)
>> #endif
>> }
>>
>> +static int device_hotplug_notifier(struct notifier_block *nfb,
>> + unsigned long action, void *hcpu)
>> +{
>> + unsigned int cpu = (unsigned long)hcpu;
>> + struct device *dev = get_cpu_device(cpu);
>> + int ret;
>> +
>> + switch (action & ~CPU_TASKS_FROZEN) {
>> + case CPU_ONLINE:
>> + dev->offline = false;
>> + ret = NOTIFY_OK;
>> + break;
>> + case CPU_DYING:
>> + dev->offline = true;
>
> one thing i just thought of here, since dev->offline is getting set
> here, can you remove it being set in drivers/base/core.c at
> device_online() and device_offline() ? That's probably redundant now
> right?

sorry ignore that; device_on|offline() is common code, not cpu-specific.

>
>
>> + ret = NOTIFY_OK;
>> + break;
>> + default:
>> + ret = NOTIFY_DONE;
>> + break;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> void __init cpu_dev_init(void)
>> {
>> if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
>> panic("Failed to register CPU subsystem");
>>
>> cpu_dev_register_generic();
>> + cpu_notifier(device_hotplug_notifier, 0);
>> }
>> --
>> 1.7.9.5
>>
>> --
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