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authorZhen Lei <thunder.leizhen@huawei.com>2022-11-19 17:25:05 +0800
committerPaul E. McKenney <paulmck@kernel.org>2023-01-05 12:21:11 -0800
commit7c182722a0a9447e31f9645de4f311e5bc59b480 (patch)
treec394fb7c54824a6bf0eb8c7c45115a73d17ad675
parentsched: Add helper kstat_cpu_softirqs_sum() (diff)
downloadwireguard-linux-7c182722a0a9447e31f9645de4f311e5bc59b480.tar.xz
wireguard-linux-7c182722a0a9447e31f9645de4f311e5bc59b480.zip
sched: Add helper nr_context_switches_cpu()
Add a function nr_context_switches_cpu() that returns number of context switches since boot on the specified CPU. This information will be used to diagnose RCU CPU stalls. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
-rw-r--r--include/linux/kernel_stat.h1
-rw-r--r--kernel/sched/core.c5
2 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 898076e173a9..9935f7ecbfb9 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 25b582b6ee5f..2e40a6c116e1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5282,6 +5282,11 @@ 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;