* [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2)
@ 2013-10-14 8:24 Namhyung Kim
2013-10-14 8:24 ` [PATCH 1/4] ftrace: Get rid of ftrace_graph_filter_enabled Namhyung Kim
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Namhyung Kim @ 2013-10-14 8:24 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Frederic Weisbecker, Ingo Molnar, LKML, Namhyung Kim
Hi Steve,
I broke the patch into pieces so that it can address what you said.
The patch 1 and 2 are cleanup and preparation you mentioned. Patch 3
is an one more cleanup I found during the work. Patch 4 is core of
this patchset and main diferrence to prior version is added comments.
This is based on the current linux-trace/for-next.
I also put this on 'ftrace/nograph-v2' branch in my tree
git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
Any comments are welcome, thanks.
Namhyung
Namhyung Kim (4):
ftrace: Get rid of ftrace_graph_filter_enabled
ftrace: Introduce struct ftrace_graph_data
ftrace: Narrow down the protected area of graph_lock
ftrace: Add set_graph_notrace filter
include/linux/ftrace.h | 1 +
kernel/trace/ftrace.c | 140 ++++++++++++++++++++++++++---------
kernel/trace/trace.h | 25 ++++++-
kernel/trace/trace_functions_graph.c | 56 +++++++++++++-
4 files changed, 181 insertions(+), 41 deletions(-)
--
1.7.11.7
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/4] ftrace: Get rid of ftrace_graph_filter_enabled
2013-10-14 8:24 [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2) Namhyung Kim
@ 2013-10-14 8:24 ` Namhyung Kim
2013-10-14 8:24 ` [PATCH 2/4] ftrace: Introduce struct ftrace_graph_data Namhyung Kim
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2013-10-14 8:24 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Frederic Weisbecker, Ingo Molnar, LKML, Namhyung Kim
From: Namhyung Kim <namhyung.kim@lge.com>
The ftrace_graph_filter_enabled means that user sets function filter
and it always has same meaning of ftrace_graph_count > 0.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/trace/ftrace.c | 6 +-----
kernel/trace/trace.h | 3 +--
2 files changed, 2 insertions(+), 7 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 03cf44ac54d3..a77e4a0142ee 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3776,7 +3776,6 @@ static const struct file_operations ftrace_notrace_fops = {
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
-int ftrace_graph_filter_enabled;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
static void *
@@ -3799,7 +3798,7 @@ static void *g_start(struct seq_file *m, loff_t *pos)
mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */
- if (!ftrace_graph_filter_enabled && !*pos)
+ if (!ftrace_graph_count && !*pos)
return (void *)1;
return __g_next(m, pos);
@@ -3845,7 +3844,6 @@ ftrace_graph_open(struct inode *inode, struct file *file)
mutex_lock(&graph_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC)) {
- ftrace_graph_filter_enabled = 0;
ftrace_graph_count = 0;
memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
}
@@ -3925,8 +3923,6 @@ out:
if (fail)
return -EINVAL;
- ftrace_graph_filter_enabled = !!(*idx);
-
return 0;
}
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 502fed770751..1ea31a7b1890 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -730,7 +730,6 @@ extern void __trace_graph_return(struct trace_array *tr,
#ifdef CONFIG_DYNAMIC_FTRACE
/* TODO: make this variable */
#define FTRACE_GRAPH_MAX_FUNCS 32
-extern int ftrace_graph_filter_enabled;
extern int ftrace_graph_count;
extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
@@ -738,7 +737,7 @@ static inline int ftrace_graph_addr(unsigned long addr)
{
int i;
- if (!ftrace_graph_filter_enabled)
+ if (!ftrace_graph_count)
return 1;
for (i = 0; i < ftrace_graph_count; i++) {
--
1.7.11.7
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/4] ftrace: Introduce struct ftrace_graph_data
2013-10-14 8:24 [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2) Namhyung Kim
2013-10-14 8:24 ` [PATCH 1/4] ftrace: Get rid of ftrace_graph_filter_enabled Namhyung Kim
@ 2013-10-14 8:24 ` Namhyung Kim
2013-10-14 8:24 ` [PATCH 3/4] ftrace: Narrow down the protected area of graph_lock Namhyung Kim
2013-10-14 8:24 ` [PATCH 4/4] ftrace: Add set_graph_notrace filter Namhyung Kim
3 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2013-10-14 8:24 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Frederic Weisbecker, Ingo Molnar, LKML, Namhyung Kim
From: Namhyung Kim <namhyung.kim@lge.com>
The struct ftrace_graph_data is for generalizing the access to
set_graph_function file. This is a preparation for adding support to
set_graph_notrace.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/trace/ftrace.c | 81 +++++++++++++++++++++++++++++++++++++++------------
1 file changed, 62 insertions(+), 19 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a77e4a0142ee..0ff3449b4272 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3641,7 +3641,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
static int __init set_graph_function(char *str)
{
@@ -3659,7 +3659,7 @@ static void __init set_ftrace_early_graph(char *buf)
func = strsep(&buf, ",");
/* we allow only one expression at a time */
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
- func);
+ FTRACE_GRAPH_MAX_FUNCS, func);
if (ret)
printk(KERN_DEBUG "ftrace: function %s not "
"traceable\n", func);
@@ -3778,12 +3778,21 @@ static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+struct ftrace_graph_data {
+ unsigned long *table;
+ size_t size;
+ int *count;
+ const struct seq_operations *seq_ops;
+};
+
static void *
__g_next(struct seq_file *m, loff_t *pos)
{
- if (*pos >= ftrace_graph_count)
+ struct ftrace_graph_data *fgd = m->private;
+
+ if (*pos >= *fgd->count)
return NULL;
- return &ftrace_graph_funcs[*pos];
+ return &fgd->table[*pos];
}
static void *
@@ -3795,10 +3804,12 @@ g_next(struct seq_file *m, void *v, loff_t *pos)
static void *g_start(struct seq_file *m, loff_t *pos)
{
+ struct ftrace_graph_data *fgd = m->private;
+
mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */
- if (!ftrace_graph_count && !*pos)
+ if (!*fgd->count && !*pos)
return (void *)1;
return __g_next(m, pos);
@@ -3834,37 +3845,68 @@ static const struct seq_operations ftrace_graph_seq_ops = {
};
static int
-ftrace_graph_open(struct inode *inode, struct file *file)
+__ftrace_graph_open(struct inode *inode, struct file *file,
+ struct ftrace_graph_data *fgd)
{
int ret = 0;
- if (unlikely(ftrace_disabled))
- return -ENODEV;
-
mutex_lock(&graph_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC)) {
- ftrace_graph_count = 0;
- memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+ *fgd->count = 0;
+ memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
}
mutex_unlock(&graph_lock);
- if (file->f_mode & FMODE_READ)
- ret = seq_open(file, &ftrace_graph_seq_ops);
+ if (file->f_mode & FMODE_READ) {
+ ret = seq_open(file, fgd->seq_ops);
+ if (!ret) {
+ struct seq_file *m = file->private_data;
+ m->private = fgd;
+ }
+ } else
+ file->private_data = fgd;
return ret;
}
static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_graph_data *fgd;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+ if (fgd == NULL)
+ return -ENOMEM;
+
+ fgd->table = ftrace_graph_funcs;
+ fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+ fgd->count = &ftrace_graph_count;
+ fgd->seq_ops = &ftrace_graph_seq_ops;
+
+ return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
- if (file->f_mode & FMODE_READ)
+ if (file->f_mode & FMODE_READ) {
+ struct seq_file *m = file->private_data;
+
+ kfree(m->private);
seq_release(inode, file);
+ } else {
+ kfree(file->private_data);
+ }
+
return 0;
}
static int
-ftrace_set_func(unsigned long *array, int *idx, char *buffer)
+ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
@@ -3877,7 +3919,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
/* decode regex */
type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
- if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+ if (!not && *idx >= size)
return -EBUSY;
search_len = strlen(search);
@@ -3905,7 +3947,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
fail = 0;
if (!exists) {
array[(*idx)++] = rec->ip;
- if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+ if (*idx >= size)
goto out;
}
} else {
@@ -3932,6 +3974,7 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
{
struct trace_parser parser;
ssize_t read, ret;
+ struct ftrace_graph_data *fgd = file->private_data;
if (!cnt)
return 0;
@@ -3949,8 +3992,8 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
parser.buffer[parser.idx] = 0;
/* we allow only one expression at a time */
- ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
- parser.buffer);
+ ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
+ parser.buffer);
if (ret)
goto out_free;
}
--
1.7.11.7
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 3/4] ftrace: Narrow down the protected area of graph_lock
2013-10-14 8:24 [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2) Namhyung Kim
2013-10-14 8:24 ` [PATCH 1/4] ftrace: Get rid of ftrace_graph_filter_enabled Namhyung Kim
2013-10-14 8:24 ` [PATCH 2/4] ftrace: Introduce struct ftrace_graph_data Namhyung Kim
@ 2013-10-14 8:24 ` Namhyung Kim
2013-10-14 8:24 ` [PATCH 4/4] ftrace: Add set_graph_notrace filter Namhyung Kim
3 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2013-10-14 8:24 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Frederic Weisbecker, Ingo Molnar, LKML, Namhyung Kim
From: Namhyung Kim <namhyung.kim@lge.com>
It seems that it doesn't need to hold graph_lock during preparation of
the trace_parser. At least it makes the code a bit simpler IMHO.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/trace/ftrace.c | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0ff3449b4272..26a229ab0c19 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3973,37 +3973,33 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
- ssize_t read, ret;
+ ssize_t read, ret = 0;
struct ftrace_graph_data *fgd = file->private_data;
if (!cnt)
return 0;
- mutex_lock(&graph_lock);
-
- if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
- ret = -ENOMEM;
- goto out_unlock;
- }
+ if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
+ return -ENOMEM;
read = trace_get_user(&parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded((&parser))) {
parser.buffer[parser.idx] = 0;
+ mutex_lock(&graph_lock);
+
/* we allow only one expression at a time */
ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
parser.buffer);
- if (ret)
- goto out_free;
+
+ mutex_unlock(&graph_lock);
}
- ret = read;
+ if (!ret)
+ ret = read;
-out_free:
trace_parser_put(&parser);
-out_unlock:
- mutex_unlock(&graph_lock);
return ret;
}
--
1.7.11.7
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 4/4] ftrace: Add set_graph_notrace filter
2013-10-14 8:24 [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2) Namhyung Kim
` (2 preceding siblings ...)
2013-10-14 8:24 ` [PATCH 3/4] ftrace: Narrow down the protected area of graph_lock Namhyung Kim
@ 2013-10-14 8:24 ` Namhyung Kim
3 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2013-10-14 8:24 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Frederic Weisbecker, Ingo Molnar, LKML, Namhyung Kim
From: Namhyung Kim <namhyung.kim@lge.com>
The set_graph_notrace filter is analogous to set_ftrace_notrace and
can be used for eliminating uninteresting part of function graph trace
output. It also works with set_graph_function nicely.
# cd /sys/kernel/debug/tracing/
# echo do_page_fault > set_graph_function
# perf ftrace live true
2) | do_page_fault() {
2) | __do_page_fault() {
2) 0.381 us | down_read_trylock();
2) 0.055 us | __might_sleep();
2) 0.696 us | find_vma();
2) | handle_mm_fault() {
2) | handle_pte_fault() {
2) | __do_fault() {
2) | filemap_fault() {
2) | find_get_page() {
2) 0.033 us | __rcu_read_lock();
2) 0.035 us | __rcu_read_unlock();
2) 1.696 us | }
2) 0.031 us | __might_sleep();
2) 2.831 us | }
2) | _raw_spin_lock() {
2) 0.046 us | add_preempt_count();
2) 0.841 us | }
2) 0.033 us | page_add_file_rmap();
2) | _raw_spin_unlock() {
2) 0.057 us | sub_preempt_count();
2) 0.568 us | }
2) | unlock_page() {
2) 0.084 us | page_waitqueue();
2) 0.126 us | __wake_up_bit();
2) 1.117 us | }
2) 7.729 us | }
2) 8.397 us | }
2) 8.956 us | }
2) 0.085 us | up_read();
2) + 12.745 us | }
2) + 13.401 us | }
...
# echo handle_mm_fault > set_graph_notrace
# perf ftrace live true
1) | do_page_fault() {
1) | __do_page_fault() {
1) 0.205 us | down_read_trylock();
1) 0.041 us | __might_sleep();
1) 0.344 us | find_vma();
1) 0.069 us | up_read();
1) 4.692 us | }
1) 5.311 us | }
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
include/linux/ftrace.h | 1 +
kernel/trace/ftrace.c | 33 +++++++++++++++++++++
kernel/trace/trace.h | 22 ++++++++++++++
kernel/trace/trace_functions_graph.c | 56 ++++++++++++++++++++++++++++++++++--
4 files changed, 109 insertions(+), 3 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9f15c0064c50..ec85d48619e1 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -721,6 +721,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
extern char __irqentry_text_start[];
extern char __irqentry_text_end[];
+#define FTRACE_NOTRACE_DEPTH 65536
#define FTRACE_RETFUNC_DEPTH 50
#define FTRACE_RETSTACK_ALLOC_SIZE 32
extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 26a229ab0c19..44e826a79665 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3776,7 +3776,9 @@ static const struct file_operations ftrace_notrace_fops = {
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
+int ftrace_graph_notrace_count;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
struct ftrace_graph_data {
unsigned long *table;
@@ -3891,6 +3893,26 @@ ftrace_graph_open(struct inode *inode, struct file *file)
}
static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_graph_data *fgd;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+ if (fgd == NULL)
+ return -ENOMEM;
+
+ fgd->table = ftrace_graph_notrace_funcs;
+ fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+ fgd->count = &ftrace_graph_notrace_count;
+ fgd->seq_ops = &ftrace_graph_seq_ops;
+
+ return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
if (file->f_mode & FMODE_READ) {
@@ -4011,6 +4033,14 @@ static const struct file_operations ftrace_graph_fops = {
.llseek = ftrace_filter_lseek,
.release = ftrace_graph_release,
};
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+ .open = ftrace_graph_notrace_open,
+ .read = seq_read,
+ .write = ftrace_graph_write,
+ .llseek = ftrace_filter_lseek,
+ .release = ftrace_graph_release,
+};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
@@ -4032,6 +4062,9 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
trace_create_file("set_graph_function", 0444, d_tracer,
NULL,
&ftrace_graph_fops);
+ trace_create_file("set_graph_notrace", 0444, d_tracer,
+ NULL,
+ &ftrace_graph_notrace_fops);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
return 0;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 1ea31a7b1890..fec2d75a733f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -732,6 +732,8 @@ extern void __trace_graph_return(struct trace_array *tr,
#define FTRACE_GRAPH_MAX_FUNCS 32
extern int ftrace_graph_count;
extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
+extern int ftrace_graph_notrace_count;
+extern unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS];
static inline int ftrace_graph_addr(unsigned long addr)
{
@@ -757,11 +759,31 @@ static inline int ftrace_graph_addr(unsigned long addr)
return 0;
}
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+ int i;
+
+ if (!ftrace_graph_notrace_count)
+ return 0;
+
+ for (i = 0; i < ftrace_graph_notrace_count; i++) {
+ if (addr == ftrace_graph_notrace_funcs[i])
+ return 1;
+ }
+
+ return 0;
+}
#else
static inline int ftrace_graph_addr(unsigned long addr)
{
return 1;
}
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+ return 0;
+}
#endif /* CONFIG_DYNAMIC_FTRACE */
#else /* CONFIG_FUNCTION_GRAPH_TRACER */
static inline enum print_line_t
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b5c09242683d..e08c030b8f38 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -114,16 +114,37 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
return -EBUSY;
}
+ /*
+ * The curr_ret_stack is an index to ftrace return stack of
+ * current task. Its value should be in [0, FTRACE_RETFUNC_
+ * DEPTH) when the function graph tracer is used. To support
+ * filtering out specific functions, it makes the index
+ * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+ * so when it sees a negative index the ftrace will ignore
+ * the record. And the index gets recovered when returning
+ * from the filtered function by adding the FTRACE_NOTRACE_
+ * DEPTH and then it'll continue to record functions normally.
+ *
+ * The curr_ret_stack is initialized to -1 and get increased
+ * in this function. So it can be less than -1 only if it was
+ * filtered out via ftrace_graph_notrace_addr() which can be
+ * set from set_graph_notrace file in debugfs by user.
+ */
+ if (current->curr_ret_stack < -1)
+ return -EBUSY;
+
calltime = trace_clock_local();
index = ++current->curr_ret_stack;
+ if (ftrace_graph_notrace_addr(func))
+ current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
barrier();
current->ret_stack[index].ret = ret;
current->ret_stack[index].func = func;
current->ret_stack[index].calltime = calltime;
current->ret_stack[index].subtime = 0;
current->ret_stack[index].fp = frame_pointer;
- *depth = index;
+ *depth = current->curr_ret_stack;
return 0;
}
@@ -137,7 +158,17 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
index = current->curr_ret_stack;
- if (unlikely(index < 0)) {
+ /*
+ * A negative index here means that it's just returned from a
+ * notrace'd function. Recover index to get an original
+ * return address. See ftrace_push_return_trace().
+ *
+ * TODO: Need to check whether the stack gets corrupted.
+ */
+ if (index < 0)
+ index += FTRACE_NOTRACE_DEPTH;
+
+ if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
@@ -193,6 +224,15 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
trace.rettime = trace_clock_local();
barrier();
current->curr_ret_stack--;
+ /*
+ * The curr_ret_stack can be less than -1 only if it was
+ * filtered out and it's about to return from the function.
+ * Recover the index and continue to trace normal functions.
+ */
+ if (current->curr_ret_stack < -1) {
+ current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+ return ret;
+ }
/*
* The trace should run after decrementing the ret counter
@@ -259,10 +299,20 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
/* trace it when it is-nested-in or is a function enabled. */
if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
- ftrace_graph_ignore_irqs()) ||
+ ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
(max_depth && trace->depth >= max_depth))
return 0;
+ /*
+ * Do not trace a function if it's filtered by set_graph_notrace.
+ * Make the index of ret stack negative to indicate that it should
+ * ignore further functions. But it needs its own ret stack entry
+ * to recover the original index in order to continue tracing after
+ * returning from the function.
+ */
+ if (ftrace_graph_notrace_addr(trace->func))
+ return 1;
+
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
--
1.7.11.7
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-10-14 8:25 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-10-14 8:24 [PATCHSET 0/4] ftrace: Add support to set_graph_notrace filter (v2) Namhyung Kim
2013-10-14 8:24 ` [PATCH 1/4] ftrace: Get rid of ftrace_graph_filter_enabled Namhyung Kim
2013-10-14 8:24 ` [PATCH 2/4] ftrace: Introduce struct ftrace_graph_data Namhyung Kim
2013-10-14 8:24 ` [PATCH 3/4] ftrace: Narrow down the protected area of graph_lock Namhyung Kim
2013-10-14 8:24 ` [PATCH 4/4] ftrace: Add set_graph_notrace filter Namhyung Kim
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