diff mbox series

[v4,3/4] sched: Add helper nr_context_switches_cpu()

Message ID 20221104021224.102-4-thunder.leizhen@huawei.com (mailing list archive)
State Superseded
Headers show
Series rcu: Add RCU stall diagnosis information | expand

Commit Message

Leizhen (ThunderTown) Nov. 4, 2022, 2:12 a.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(+)
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 06e268c15f14ae4..380c521170d68f3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5234,6 +5234,11 @@  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;