diff mbox series

kernel: Ftrace seems to have functions to improve performance through optimization through optimization

Message ID 20220513021314.59480-1-kunyu@nfschina.com (mailing list archive)
State New, archived
Headers show
Series kernel: Ftrace seems to have functions to improve performance through optimization through optimization | expand

Commit Message

Li kunyu May 13, 2022, 2:13 a.m. UTC 
such as ftrace_ARCH_code_*, return 0, so the FTRACE_* check is not required

Signed-off-by: Li kunyu <kunyu@nfschina.com>
---
 arch/arm/kernel/ftrace.c   |  6 ++----
 arch/riscv/kernel/ftrace.c |  6 ++----
 arch/s390/kernel/ftrace.c  |  3 +--
 arch/x86/kernel/ftrace.c   |  6 ++----
 include/linux/ftrace.h     |  4 ++--
 kernel/trace/ftrace.c      | 16 ++++------------
 6 files changed, 13 insertions(+), 28 deletions(-)

Comments

Steven Rostedt May 17, 2022, 2:13 p.m. UTC | #1 
On Fri, 13 May 2022 10:13:14 +0800
Li kunyu <kunyu@nfschina.com> wrote:

> Subject: [PATCH] kernel: Ftrace seems to have functions to improve performance through optimization  through optimization

Did you forget to add a subject line. The above looks to be the beginning
of the paragraph below.


> Date: Fri, 13 May 2022 10:13:14 +0800
> Message-Id: <20220513021314.59480-1-kunyu@nfschina.com>
> 
> such as ftrace_ARCH_code_*, return 0, so the FTRACE_* check is not required

And even combined, the above makes no sense.

This patch is not an optimization patch. If it were, the optimization
provided is so small, it's not worth adding it.

Just state that it's a clean up (I already told you this). Here, I'll do
the work for you (but I expect a proper patch):

  Subject: [PATCH v2] ftrace: Remove return value of ftrace_arch_modify_*()

  All instances of the function ftrace_arch_modify_prepare() and
  ftrace_arch_modify_post_process() return zero. There's no point in
  checking their return value. Just have them be void functions.

There, that's what I would like to see.

-- Steve


> 
> Signed-off-by: Li kunyu <kunyu@nfschina.com>
diff mbox series

Patch

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 83cc068586bc..a0b6d1e3812f 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -79,16 +79,14 @@  static unsigned long __ref adjust_address(struct dyn_ftrace *rec,
 	return (unsigned long)&ftrace_regs_caller_from_init;
 }
 
-int ftrace_arch_code_modify_prepare(void)
+void ftrace_arch_code_modify_prepare(void)
 {
-	return 0;
 }
 
-int ftrace_arch_code_modify_post_process(void)
+void ftrace_arch_code_modify_post_process(void)
 {
 	/* Make sure any TLB misses during machine stop are cleared. */
 	flush_tlb_all();
-	return 0;
 }
 
 static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr,
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 4716f4cdc038..2086f6585773 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -12,16 +12,14 @@ 
 #include <asm/patch.h>
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-int ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex)
+void ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex)
 {
 	mutex_lock(&text_mutex);
-	return 0;
 }
 
-int ftrace_arch_code_modify_post_process(void) __releases(&text_mutex)
+void ftrace_arch_code_modify_post_process(void) __releases(&text_mutex)
 {
 	mutex_unlock(&text_mutex);
-	return 0;
 }
 
 static int ftrace_check_current_call(unsigned long hook_pos,
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 1852d46babb1..416b5a94353d 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -225,14 +225,13 @@  void arch_ftrace_update_code(int command)
 	ftrace_modify_all_code(command);
 }
 
-int ftrace_arch_code_modify_post_process(void)
+void ftrace_arch_code_modify_post_process(void)
 {
 	/*
 	 * Flush any pre-fetched instructions on all
 	 * CPUs to make the new code visible.
 	 */
 	text_poke_sync_lock();
-	return 0;
 }
 
 #ifdef CONFIG_MODULES
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1e31c7d21597..73d2719ed12c 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -37,7 +37,7 @@ 
 
 static int ftrace_poke_late = 0;
 
-int ftrace_arch_code_modify_prepare(void)
+void ftrace_arch_code_modify_prepare(void)
     __acquires(&text_mutex)
 {
 	/*
@@ -47,10 +47,9 @@  int ftrace_arch_code_modify_prepare(void)
 	 */
 	mutex_lock(&text_mutex);
 	ftrace_poke_late = 1;
-	return 0;
 }
 
-int ftrace_arch_code_modify_post_process(void)
+void ftrace_arch_code_modify_post_process(void)
     __releases(&text_mutex)
 {
 	/*
@@ -61,7 +60,6 @@  int ftrace_arch_code_modify_post_process(void)
 	text_poke_finish();
 	ftrace_poke_late = 0;
 	mutex_unlock(&text_mutex);
-	return 0;
 }
 
 static const char *ftrace_nop_replace(void)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4816b7e11047..a5f74f6e7e4e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -449,8 +449,8 @@  static inline void stack_tracer_enable(void) { }
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-int ftrace_arch_code_modify_prepare(void);
-int ftrace_arch_code_modify_post_process(void);
+void ftrace_arch_code_modify_prepare(void);
+void ftrace_arch_code_modify_post_process(void);
 
 enum ftrace_bug_type {
 	FTRACE_BUG_UNKNOWN,
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4f1d2f5e7263..35a899f136fe 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2707,18 +2707,16 @@  ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
  * archs can override this function if they must do something
  * before the modifying code is performed.
  */
-int __weak ftrace_arch_code_modify_prepare(void)
+void __weak ftrace_arch_code_modify_prepare(void)
 {
-	return 0;
 }
 
 /*
  * archs can override this function if they must do something
  * after the modifying code is performed.
  */
-int __weak ftrace_arch_code_modify_post_process(void)
+void __weak ftrace_arch_code_modify_post_process(void)
 {
-	return 0;
 }
 
 void ftrace_modify_all_code(int command)
@@ -2804,12 +2802,7 @@  void __weak arch_ftrace_update_code(int command)
 
 static void ftrace_run_update_code(int command)
 {
-	int ret;
-
-	ret = ftrace_arch_code_modify_prepare();
-	FTRACE_WARN_ON(ret);
-	if (ret)
-		return;
+	ftrace_arch_code_modify_prepare();
 
 	/*
 	 * By default we use stop_machine() to modify the code.
@@ -2819,8 +2812,7 @@  static void ftrace_run_update_code(int command)
 	 */
 	arch_ftrace_update_code(command);
 
-	ret = ftrace_arch_code_modify_post_process();
-	FTRACE_WARN_ON(ret);
+	ftrace_arch_code_modify_post_process();
 }
 
 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,