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platform_kernel-5.15
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ftrace: nmi update statistics 

Impact: add more debug info to /debugfs/tracing/dyn_ftrace_total_info

This patch adds dynamic ftrace NMI update statistics to the
/debugfs/tracing/dyn_ftrace_total_info stat file.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-10-30 16:08:33 -04:00 committed by Ingo Molnar
parent 17666f02b1
commit b807c3d0f8
2 changed files with 48 additions and 9 deletions
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26
arch/x86/kernel/ftrace.c
View File

@ -91,6 +91,19 @@ static int mod_code_write;
static void *mod_code_ip; static void *mod_code_ip;
static void *mod_code_newcode; static void *mod_code_newcode;
static int nmi_wait_count;
static atomic_t nmi_update_count;
int ftrace_arch_read_dyn_info(char *buf, int size)
{
int r;
r = snprintf(buf, size, "%u %u",
nmi_wait_count,
atomic_read(&nmi_update_count));
return r;
}
static void ftrace_mod_code(void) static void ftrace_mod_code(void)
{ {
/* /*
@ -109,8 +122,10 @@ void ftrace_nmi_enter(void)
atomic_inc(&in_nmi); atomic_inc(&in_nmi);
/* Must have in_nmi seen before reading write flag */ /* Must have in_nmi seen before reading write flag */
smp_mb(); smp_mb();
if (mod_code_write) if (mod_code_write) {
ftrace_mod_code(); ftrace_mod_code();
atomic_inc(&nmi_update_count);
}
} }
void ftrace_nmi_exit(void) void ftrace_nmi_exit(void)
@ -122,8 +137,15 @@ void ftrace_nmi_exit(void)
static void wait_for_nmi(void) static void wait_for_nmi(void)
{ {
while (atomic_read(&in_nmi)) int waited = 0;
while (atomic_read(&in_nmi)) {
waited = 1;
cpu_relax(); cpu_relax();
}
if (waited)
nmi_wait_count++;
} }
static int static int

31
kernel/trace/trace.c
View File

@ -2815,22 +2815,39 @@ static struct file_operations tracing_mark_fops = {
#ifdef CONFIG_DYNAMIC_FTRACE #ifdef CONFIG_DYNAMIC_FTRACE
#define DYN_INFO_BUF_SIZE 1023
static char ftrace_dyn_info_buffer[DYN_INFO_BUF_SIZE+1];
static DEFINE_MUTEX(dyn_info_mutex);
int __weak ftrace_arch_read_dyn_info(char *buf, int size)
{
return 0;
}
static ssize_t static ssize_t
tracing_read_long(struct file *filp, char __user *ubuf, tracing_read_dyn_info(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos) size_t cnt, loff_t *ppos)
{ {
unsigned long *p = filp->private_data; unsigned long *p = filp->private_data;
char buf[64]; char *buf = ftrace_dyn_info_buffer;
int r; int r;
r = sprintf(buf, "%ld\n", *p); mutex_lock(&dyn_info_mutex);
r = sprintf(buf, "%ld ", *p);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); r += ftrace_arch_read_dyn_info(buf+r, DYN_INFO_BUF_SIZE-r);
buf[r++] = '\n';
r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
mutex_unlock(&dyn_info_mutex);
return r;
} }
static struct file_operations tracing_read_long_fops = { static struct file_operations tracing_dyn_info_fops = {
.open = tracing_open_generic, .open = tracing_open_generic,
.read = tracing_read_long, .read = tracing_read_dyn_info,
}; };
#endif #endif
@ -2939,7 +2956,7 @@ static __init int tracer_init_debugfs(void)
#ifdef CONFIG_DYNAMIC_FTRACE #ifdef CONFIG_DYNAMIC_FTRACE
entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer, entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
&ftrace_update_tot_cnt, &ftrace_update_tot_cnt,
&tracing_read_long_fops); &tracing_dyn_info_fops);
if (!entry) if (!entry)
pr_warning("Could not create debugfs " pr_warning("Could not create debugfs "
"'dyn_ftrace_total_info' entry\n"); "'dyn_ftrace_total_info' entry\n");