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Message-Id: <20220512063017.57412-1-kunyu@nfschina.com>
Date: Thu, 12 May 2022 14:30:17 +0800
From: Li kunyu <kunyu@...china.com>
To: rostedt@...dmis.org, mingo@...hat.com, linux@...linux.org.uk,
paul.walmsley@...ive.com, palmer@...belt.com,
aou@...s.berkeley.edu, hca@...ux.ibm.com, gor@...ux.ibm.com,
agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
svens@...ux.ibm.com, tglx@...utronix.de, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
Li kunyu <kunyu@...china.com>
Subject: [PATCH] kernel: Ftrace seems to have functions to improve performance through optimization
At present, it is found that two functions could be optimized, and the
performance may be improved.
Signed-off-by: Li kunyu <kunyu@...china.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(-)
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,
--
2.18.2
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