[PATCH v5 2/7] sched, smp: Trace IPIs sent via send_call_function_single_ipi()

Valentin Schneider
2023-03-07T15:00:33Z

send_call_function_single_ipi() is the thing that sends IPIs at the bottom
of smp_call_function*() via either generic_exec_single() or
smp_call_function_many_cond(). Give it an IPI-related tracepoint.

Note that this ends up tracing any IPI sent via __smp_call_single_queue(),
which covers __ttwu_queue_wakelist() and irq_work_queue_on() "for free".

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
---
arch/arm/kernel/smp.c | 3 ---
arch/arm64/kernel/smp.c | 1 -
kernel/sched/core.c | 7 +++++--
kernel/smp.c | 4 ++++
4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 0b8c25763adc3..b6c832e195427 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,9 +48,6 @@
#include <asm/mach/arch.h>
#include <asm/mpu.h>

-#define CREATE_TRACE_POINTS
-#include <trace/events/ipi.h>
-
/*
* as from 2.5, kernels no longer have an init_tasks structure
* so we need some other way of telling a new secondary core
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 4e83272642552..438c16fc44633 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
#include <asm/ptrace.h>
#include <asm/virt.h>

-#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>

DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index af017e038b482..85114f75f1c9c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -81,6 +81,7 @@
#include <linux/sched/rseq_api.h>
#include <trace/events/sched.h>
#undef CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>

#include "sched.h"
#include "stats.h"
@@ -3830,10 +3831,12 @@ void send_call_function_single_ipi(int cpu)
{
struct rq *rq = cpu_rq(cpu);

- if (!set_nr_if_polling(rq->idle))
+ if (!set_nr_if_polling(rq->idle)) {
+ trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
arch_send_call_function_single_ipi(cpu);
- else
+ } else {
trace_sched_wake_idle_without_ipi(cpu);
+ }
}

/*
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14a..e2ca1e2f31274 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,10 @@
#include <linux/sched/debug.h>
#include <linux/jump_label.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+#undef CREATE_TRACE_POINTS
+
#include "smpboot.h"
#include "sched/smp.h"

--
2.31.1