linux-kernel - [tip: smp/core] sched, smp: Trace IPIs sent via send_call_function_single

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Message-ID: <167999248631.5837.6674946507911418669.tip-bot2@tip-bot2>
Date:   Tue, 28 Mar 2023 08:34:46 -0000
From:   "tip-bot2 for Valentin Schneider" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Valentin Schneider <vschneid@...hat.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        "Steven Rostedt (Google)" <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: smp/core] sched, smp: Trace IPIs sent via
 send_call_function_single_ipi()

The following commit has been merged into the smp/core branch of tip:

Commit-ID:     cc9cb0a71725aa8dd8d8f534a9b562bbf7981f75
Gitweb:        https://git.kernel.org/tip/cc9cb0a71725aa8dd8d8f534a9b562bbf7981f75
Author:        Valentin Schneider <vschneid@...hat.com>
AuthorDate:    Tue, 07 Mar 2023 14:35:53 
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Fri, 24 Mar 2023 11:01:27 +01:00

sched, smp: Trace IPIs sent via send_call_function_single_ipi()

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@...hat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Acked-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20230307143558.294354-3-vschneid@redhat.com
---
 arch/arm/kernel/smp.c   |  1 -
 arch/arm64/kernel/smp.c |  1 -
 kernel/sched/core.c     |  9 +++++++--
 kernel/smp.c            |  2 ++
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 0b8c257..5edf092 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,7 +48,6 @@
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
 /*
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 4e83272..438c16f 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 488655f..c26a2cd 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -80,6 +80,7 @@
 #define CREATE_TRACE_POINTS
 #include <linux/sched/rseq_api.h>
 #include <trace/events/sched.h>
+#include <trace/events/ipi.h>
 #undef CREATE_TRACE_POINTS
 
 #include "sched.h"
@@ -95,6 +96,8 @@
 #include "../../io_uring/io-wq.h"
 #include "../smpboot.h"
 
+EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpumask);
+
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
  * associated with them) to allow external modules to probe them.
@@ -3830,10 +3833,12 @@ 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 298ba75..770e879 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,6 +26,8 @@
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
 
+#include <trace/events/ipi.h>
+
 #include "smpboot.h"
 #include "sched/smp.h"