[RFC,v2,6/8] treewide: Trace IPIs sent via smp_send_reschedule()

Commit Message

Valentin Schneider Nov. 2, 2022, 6:33 p.m. UTC

To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Signed-off-by: Valentin Schneider <[e-mail]>
[csky bits]
Acked-by: Guo Ren <[e-mail]>
---
 arch/alpha/kernel/smp.c          | 2 +-
 arch/arc/kernel/smp.c            | 2 +-
 arch/arm/kernel/smp.c            | 2 +-
 arch/arm64/kernel/smp.c          | 2 +-
 arch/csky/kernel/smp.c           | 2 +-
 arch/hexagon/kernel/smp.c        | 2 +-
 arch/ia64/kernel/smp.c           | 4 ++--
 arch/loongarch/include/asm/smp.h | 2 +-
 arch/mips/include/asm/smp.h      | 2 +-
 arch/openrisc/kernel/smp.c       | 2 +-
 arch/parisc/kernel/smp.c         | 4 ++--
 arch/powerpc/kernel/smp.c        | 4 ++--
 arch/powerpc/kvm/book3s_hv.c     | 1 +
 arch/riscv/kernel/smp.c          | 4 ++--
 arch/s390/kernel/smp.c           | 2 +-
 arch/sh/kernel/smp.c             | 2 +-
 arch/sparc/kernel/smp_32.c       | 2 +-
 arch/sparc/kernel/smp_64.c       | 2 +-
 arch/x86/include/asm/smp.h       | 2 +-
 arch/x86/kvm/svm/svm.c           | 1 +
 arch/x86/kvm/x86.c               | 1 +
 arch/xtensa/kernel/smp.c         | 2 +-
 include/linux/smp.h              | 2 +-
 kernel/smp.c                     | 8 ++++++++
 24 files changed, 35 insertions(+), 24 deletions(-)

Comments

Peter Zijlstra Nov. 17, 2022, 9:12 a.m. UTC | #1

On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:

> diff --git a/kernel/smp.c b/kernel/smp.c
> index c4d561cf50d45..44fa4b9b1f46b 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>  	arch_send_call_function_ipi_mask(mask);
>  }
>  
> +void smp_send_reschedule(int cpu)
> +{
> +	/* XXX scheduler_ipi is inline :/ */
> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
> +	arch_smp_send_reschedule(cpu);
> +}
> +EXPORT_SYMBOL_GPL(smp_send_reschedule);

Yeah, no.. I see some crazy archs do this, but no we're not exporting
this in generic.

Valentin Schneider Nov. 17, 2022, 2:24 p.m. UTC | #2

On 17/11/22 10:12, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 06:33:34PM +0000, Valentin Schneider wrote:
>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index c4d561cf50d45..44fa4b9b1f46b 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -167,6 +167,14 @@ send_call_function_ipi_mask(const struct cpumask *mask)
>>      arch_send_call_function_ipi_mask(mask);
>>  }
>>
>> +void smp_send_reschedule(int cpu)
>> +{
>> +	/* XXX scheduler_ipi is inline :/ */
>> +	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
>> +	arch_smp_send_reschedule(cpu);
>> +}
>> +EXPORT_SYMBOL_GPL(smp_send_reschedule);
>
> Yeah, no.. I see some crazy archs do this, but no we're not exporting
> this in generic.

So the list is: ia64, powerpc, riscv
and they all seem to do it because of KVM:
  c4cb768f0277 ("[IA64] export smp_send_reschedule")
  de56a948b918 ("KVM: PPC: Add support for Book3S processors in hypervisor mode")
  d3d7a0ce020e ("RISC-V: Export kernel symbols for kvm")

Other archs get out of it either because their smp_send_reschedule() is
inline (e.g. x86), or because they don't allow building KVM as a module
(e.g. arm64).

If I can cobble the tracepoint+reschedule in an inline helper, then that
wouldn't require any new exports - I'm fighting a bit with the header maze
ATM, but hopefully I can get somewhere with this.

Patch

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4e20f75438f8..38637eb9eebd5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@  handle_ipi(struct pt_regs *regs)
 }
 
 void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
 {
 #ifdef DEBUG_IPI_MSG
 	if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77d..409cfa4675b40 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@  static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
 		ipi_send_msg_one(cpu, msg);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	ipi_send_msg_one(cpu, IPI_RESCHEDULE);
 }
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3b280d55c1c40..f216ac890b6f9 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -745,7 +745,7 @@  void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 937d2623e06ba..8d108edc4a89f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -976,7 +976,7 @@  void __init set_smp_ipi_range(int ipi_base, int n)
 	ipi_setup(smp_processor_id());
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 4b605aa2e1d65..fd7f81be16dd6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@  void smp_send_stop(void)
 	on_each_cpu(ipi_stop, NULL, 1);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c4..4e8bee25b8c68 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@  void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc2..ea4f009a232b4 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@  kdump_smp_send_init(void)
  * Called with preemption disabled.
  */
 void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
 {
 	ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 /*
  * Called with preemption disabled.
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 71189b28bfb27..3fcca134dfb1b 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -83,7 +83,7 @@  extern void show_ipi_list(struct seq_file *p, int prec);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	loongson3_send_ipi_single(cpu, SMP_RESCHEDULE);
 }
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 5d9ff61004ca7..9806e79895d99 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@  extern void calculate_cpu_foreign_map(void);
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	extern const struct plat_smp_ops *mp_ops;	/* private */
 
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0a..0a7a059e2dff4 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@  void handle_IPI(unsigned int ipi_msg)
 	}
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae38..b7fc859fa87db 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@  void kgdb_roundup_cpus(void)
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
 
-void 
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 
 void
 smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0da6e59161cd4..2f85a757ee792 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -364,12 +364,12 @@  static inline void do_message_pass(int cpu, int msg)
 #endif
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (likely(smp_ops))
 		do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
 void arch_send_call_function_single_ipi(int cpu)
 {
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190bd..686c80b17627e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@ 
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/smp.h>
 
 #include <asm/ftrace.h>
 #include <asm/reg.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c585..213602e89a8b2 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -235,8 +235,8 @@  void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0031325ce4bc9..6c4da1e26e568 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@  void arch_send_call_function_single_ipi(int cpu)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec2459..5cf35a774dc70 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@  void __init smp_cpus_done(unsigned int max_cpus)
 	       (bogosum / (5000/HZ)) % 100);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
 }
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eba..87eaa7719fa27 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@  void cpu_panic(void)
 
 struct linux_prom_registers smp_penguin_ctable = { 0 };
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	/*
 	 * CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b9244..e5964d1d8b37d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@  static unsigned long send_cpu_poke(int cpu)
 	return hv_err;
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	if (cpu == smp_processor_id()) {
 		WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a73bced40e241..5ff5815149bd3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@  static inline void play_dead(void)
 	smp_ops.play_dead();
 }
 
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
 {
 	smp_ops.smp_send_reschedule(cpu);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58f0077d93579..b972c6f8c1791 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -26,6 +26,7 @@ 
 #include <linux/swap.h>
 #include <linux/rwsem.h>
 #include <linux/cc_platform.h>
+#include <linux/smp.h>
 
 #include <asm/apic.h>
 #include <asm/perf_event.h>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 521b433f978c7..3fbc3fea3e754 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@ 
 #include <linux/mem_encrypt.h>
 #include <linux/entry-kvm.h>
 #include <linux/suspend.h>
+#include <linux/smp.h>
 
 #include <trace/events/kvm.h>
 
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 4dc109dd6214e..d95907b8e4d38 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -389,7 +389,7 @@  void arch_send_call_function_single_ipi(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 }
 
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a80ab58ae3f1d..2f9dc1b7a7fb6 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,9 +125,9 @@  extern void smp_send_stop(void);
 /*
  * sends a 'reschedule' event to another CPU:
  */
+extern void arch_smp_send_reschedule(int cpu);
 extern void smp_send_reschedule(int cpu);
 
-
 /*
  * Prepare machine for booting other CPUs.
  */
diff --git a/kernel/smp.c b/kernel/smp.c
index c4d561cf50d45..44fa4b9b1f46b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -167,6 +167,14 @@  send_call_function_ipi_mask(const struct cpumask *mask)
 	arch_send_call_function_ipi_mask(mask);
 }
 
+void smp_send_reschedule(int cpu)
+{
+	/* XXX scheduler_ipi is inline :/ */
+	trace_ipi_send_cpumask(cpumask_of(cpu), _RET_IP_, NULL);
+	arch_smp_send_reschedule(cpu);
+}
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
+
 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
 
 static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);