diff mbox

[RFCv5,45/46] sched/cpufreq_sched: modify pcpu_capacity handling

Message ID 1436293469-25707-46-git-send-email-morten.rasmussen@arm.com (mailing list archive)
State RFC
Headers show

Commit Message

Morten Rasmussen July 7, 2015, 6:24 p.m. UTC 
From: Juri Lelli <juri.lelli@arm.com>

Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
as the thing can be called remotely (e.g., from load balacing code).

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
---
 kernel/sched/cpufreq_sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michael Turquette July 8, 2015, 4:42 p.m. UTC | #1 
Quoting Morten Rasmussen (2015-07-07 11:24:28)
> From: Juri Lelli <juri.lelli@arm.com>
> 
> Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
> as the thing can be called remotely (e.g., from load balacing code).
> 
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
> 
> Signed-off-by: Juri Lelli <juri.lelli@arm.com>

Looks good to me. Feel free to add my Reviewed-by or Acked-by as
appropriate.

Regards,
Mike

> ---
>  kernel/sched/cpufreq_sched.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
> index 06ff183..b81ac779 100644
> --- a/kernel/sched/cpufreq_sched.c
> +++ b/kernel/sched/cpufreq_sched.c
> @@ -151,7 +151,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
>         unsigned long capacity_max = 0;
>  
>         /* update per-cpu capacity request */
> -       __this_cpu_write(pcpu_capacity, capacity);
> +       per_cpu(pcpu_capacity, cpu) = capacity;
>  
>         policy = cpufreq_cpu_get(cpu);
>         if (IS_ERR_OR_NULL(policy)) {
> -- 
> 1.9.1
> 
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Juri Lelli July 9, 2015, 4:55 p.m. UTC | #2 
Hi Mike,

On 08/07/15 17:42, Michael Turquette wrote:
> Quoting Morten Rasmussen (2015-07-07 11:24:28)
>> From: Juri Lelli <juri.lelli@arm.com>
>>
>> Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
>> as the thing can be called remotely (e.g., from load balacing code).
>>
>> cc: Ingo Molnar <mingo@redhat.com>
>> cc: Peter Zijlstra <peterz@infradead.org>
>>
>> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
> 
> Looks good to me. Feel free to add my Reviewed-by or Acked-by as
> appropriate.
> 

Thanks for reviewing it! :)

Best,

- Juri

> Regards,
> Mike
> 
>> ---
>>  kernel/sched/cpufreq_sched.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
>> index 06ff183..b81ac779 100644
>> --- a/kernel/sched/cpufreq_sched.c
>> +++ b/kernel/sched/cpufreq_sched.c
>> @@ -151,7 +151,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
>>         unsigned long capacity_max = 0;
>>  
>>         /* update per-cpu capacity request */
>> -       __this_cpu_write(pcpu_capacity, capacity);
>> +       per_cpu(pcpu_capacity, cpu) = capacity;
>>  
>>         policy = cpufreq_cpu_get(cpu);
>>         if (IS_ERR_OR_NULL(policy)) {
>> -- 
>> 1.9.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> 

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Peter Zijlstra Aug. 16, 2015, 8:35 p.m. UTC | #3 
On Tue, Jul 07, 2015 at 07:24:28PM +0100, Morten Rasmussen wrote:
> From: Juri Lelli <juri.lelli@arm.com>
> 
> Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
> as the thing can be called remotely (e.g., from load balacing code).
> 
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
> 
> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
> ---
>  kernel/sched/cpufreq_sched.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
> index 06ff183..b81ac779 100644
> --- a/kernel/sched/cpufreq_sched.c
> +++ b/kernel/sched/cpufreq_sched.c
> @@ -151,7 +151,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
>  	unsigned long capacity_max = 0;
>  
>  	/* update per-cpu capacity request */
> -	__this_cpu_write(pcpu_capacity, capacity);
> +	per_cpu(pcpu_capacity, cpu) = capacity;
>  
>  	policy = cpufreq_cpu_get(cpu);
>  	if (IS_ERR_OR_NULL(policy)) {

Uhm,.. this function seems to hard assume its called for the local CPU.
It will only use the irq_queue_work_on() if the cpufreq thing requires
the thread, otherwise it will call the method directly on the calling
cpu.
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Juri Lelli Aug. 17, 2015, 11:16 a.m. UTC | #4 
Hi Peter,

On 16/08/15 21:35, Peter Zijlstra wrote:
> On Tue, Jul 07, 2015 at 07:24:28PM +0100, Morten Rasmussen wrote:
>> From: Juri Lelli <juri.lelli@arm.com>
>>
>> Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
>> as the thing can be called remotely (e.g., from load balacing code).
>>
>> cc: Ingo Molnar <mingo@redhat.com>
>> cc: Peter Zijlstra <peterz@infradead.org>
>>
>> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
>> ---
>>  kernel/sched/cpufreq_sched.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
>> index 06ff183..b81ac779 100644
>> --- a/kernel/sched/cpufreq_sched.c
>> +++ b/kernel/sched/cpufreq_sched.c
>> @@ -151,7 +151,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
>>  	unsigned long capacity_max = 0;
>>  
>>  	/* update per-cpu capacity request */
>> -	__this_cpu_write(pcpu_capacity, capacity);
>> +	per_cpu(pcpu_capacity, cpu) = capacity;
>>  
>>  	policy = cpufreq_cpu_get(cpu);
>>  	if (IS_ERR_OR_NULL(policy)) {
> 
> Uhm,.. this function seems to hard assume its called for the local CPU.
> It will only use the irq_queue_work_on() if the cpufreq thing requires
> the thread, otherwise it will call the method directly on the calling
> cpu.
> 

True, but we still retrieve policy from cpu passed as argument; and
then we use policy to request a freq transition, that should end up
updating the right cpu.

Thanks,

- Juri

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diff mbox

Patch

diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
index 06ff183..b81ac779 100644
--- a/kernel/sched/cpufreq_sched.c
+++ b/kernel/sched/cpufreq_sched.c
@@ -151,7 +151,7 @@  void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
 	unsigned long capacity_max = 0;
 
 	/* update per-cpu capacity request */
-	__this_cpu_write(pcpu_capacity, capacity);
+	per_cpu(pcpu_capacity, cpu) = capacity;
 
 	policy = cpufreq_cpu_get(cpu);
 	if (IS_ERR_OR_NULL(policy)) {