diff mbox series

[v5,3/4] sched: Add helper nr_context_switches_cpu()

Message ID 20221104141118.119-4-thunder.leizhen@huawei.com (mailing list archive)
State Superseded
Commit 47d08997a1e82dc2e8a6b6d8dc8fc0d3be09babb
Headers show
Series rcu: Add RCU stall diagnosis information | expand

Commit Message

Leizhen (ThunderTown) Nov. 4, 2022, 2:11 p.m. UTC 
Returns the number of context switches on the specified CPU, which can be
used to diagnose rcu stall.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 include/linux/kernel_stat.h | 1 +
 kernel/sched/core.c         | 5 +++++
 2 files changed, 6 insertions(+)

Comments

Mukesh Ojha Nov. 8, 2022, 2:33 p.m. UTC | #1 
Hi,

On 11/4/2022 7:41 PM, Zhen Lei wrote:
> Returns the number of context switches on the specified CPU, which can be
> used to diagnose rcu stall.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > ---
>   include/linux/kernel_stat.h | 1 +
>   kernel/sched/core.c         | 5 +++++
>   2 files changed, 6 insertions(+)
> 
> diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
> index 898076e173a928a..9935f7ecbfb9e31 100644
> --- a/include/linux/kernel_stat.h
> +++ b/include/linux/kernel_stat.h
> @@ -52,6 +52,7 @@ DECLARE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
>   #define kstat_cpu(cpu) per_cpu(kstat, cpu)
>   #define kcpustat_cpu(cpu) per_cpu(kernel_cpustat, cpu)
>   
> +extern unsigned long long nr_context_switches_cpu(int cpu);
>   extern unsigned long long nr_context_switches(void);
>   
>   extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 5800b0623ff3068..a0d19f67f2046d9 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5229,6 +5229,11 @@ bool single_task_running(void)
>   }
>   EXPORT_SYMBOL(single_task_running);
>   
> +unsigned long long nr_context_switches_cpu(int cpu)
> +{
> +	return cpu_rq(cpu)->nr_switches;
> +}
> +
>   unsigned long long nr_context_switches(void)
>   {
>   	int i;

LGTM.
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>

-Mukesh
diff mbox series

Patch

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 898076e173a928a..9935f7ecbfb9e31 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -52,6 +52,7 @@  DECLARE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
 #define kstat_cpu(cpu) per_cpu(kstat, cpu)
 #define kcpustat_cpu(cpu) per_cpu(kernel_cpustat, cpu)
 
+extern unsigned long long nr_context_switches_cpu(int cpu);
 extern unsigned long long nr_context_switches(void);
 
 extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5800b0623ff3068..a0d19f67f2046d9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5229,6 +5229,11 @@  bool single_task_running(void)
 }
 EXPORT_SYMBOL(single_task_running);
 
+unsigned long long nr_context_switches_cpu(int cpu)
+{
+	return cpu_rq(cpu)->nr_switches;
+}
+
 unsigned long long nr_context_switches(void)
 {
 	int i;