Re: [PATCH v11 9/9] cpuset: Allow reporting of sched domain generation info

[Waiman Long]

On 07/19/2018 09:54 AM, Peter Zijlstra wrote:
> On Sun, Jun 24, 2018 at 03:30:40PM +0800, Waiman Long wrote:
>> This patch enables us to report sched domain generation information.
>>
>> If DYNAMIC_DEBUG is enabled, issuing the following command
>>
>>   echo "file cpuset.c +p" > /sys/kernel/debug/dynamic_debug/control
>>
>> and setting loglevel to 8 will allow the kernel to show what scheduling
>> domain changes are being made.
>>
>> Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
>> ---
>>  kernel/cgroup/cpuset.c | 18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>>
>> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
>> index 07a5575..62b7e61 100644
>> --- a/kernel/cgroup/cpuset.c
>> +++ b/kernel/cgroup/cpuset.c
>> @@ -836,6 +836,23 @@ static int generate_sched_domains(cpumask_var_t **domains,
>>  	return ndoms;
>>  }
>>  
>> +#ifdef CONFIG_DEBUG_KERNEL
>> +static inline void debug_print_domains(cpumask_var_t *doms, int ndoms)
>> +{
>> +	int i;
>> +	char buf[200];
>> +	char *ptr, *end = buf + sizeof(buf) - 1;
>> +
>> +	for (i = 0, ptr = buf, *end = '\0'; i < ndoms; i++)
>> +		ptr += snprintf(ptr, end - ptr, "dom%d=%*pbl ", i,
>> +				cpumask_pr_args(doms[i]));
>> +
>> +	pr_debug("Generated %d domains: %s\n", ndoms, buf);
>> +}
>> +#else
>> +static inline void debug_print_domains(cpumask_var_t *doms, int ndoms) { }
>> +#endif
> I still hate this patch.. it prints information already available in
> sched_debug and has that rediculous on-stack buffer.

This patch is just for my own testing purpose. We can certainly drop that.

Tejun, please drop this one.

Thanks,
Longman