mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 13:41:51 +00:00
349e8d2611
It is not easy for users to get the accurate byte offset or the line number where a local variable can be probed. With '--range' option, local variables in the scope of the probe point are showed with a byte offset range, and can be added according to this range information. For example, there are some variables in the function generic_perform_write(): <generic_perform_write@mm/filemap.c:0> 0 ssize_t generic_perform_write(struct file *file, 1 struct iov_iter *i, loff_t pos) 2 { 3 struct address_space *mapping = file->f_mapping; 4 const struct address_space_operations *a_ops = mapping->a_ops; ... 42 status = a_ops->write_begin(file, mapping, pos, bytes, flags, &page, &fsdata); 44 if (unlikely(status < 0)) But we fail when we try to probe the variable 'a_ops' at line 42 or 44. $ perf probe --add 'generic_perform_write:42 a_ops' Failed to find the location of a_ops at this address. Perhaps, it has been optimized out. This is because the source code do not match the assembly, so a variable may not be available in the source code line where it appears. After this patch, we can lookup the accurate byte offset range of a variable, 'INV' indicates that this variable is not valid at the given point, but available in the scope: $ perf probe --vars 'generic_perform_write:42' --range Available variables at generic_perform_write:42 @<generic_perform_write+141> [INV] ssize_t written @<generic_perform_write+[324-331]> [INV] struct address_space_operations* a_ops @<generic_perform_write+[55-61,170-176,223-246]> [VAL] (unknown_type) fsdata @<generic_perform_write+[70-307,346-411]> [VAL] loff_t pos @<generic_perform_write+[0-286,286-336,346-411]> [VAL] long int status @<generic_perform_write+[83-342,346-411]> [VAL] long unsigned int bytes @<generic_perform_write+[122-311,320-338,346-403,403-411]> [VAL] struct address_space* mapping @<generic_perform_write+[35-344,346-411]> [VAL] struct iov_iter* i @<generic_perform_write+[0-340,346-411]> [VAL] struct page* page @<generic_perform_write+[70-307,346-411]> Then it is more clear for us to add a probe with this variable: $ perf probe --add 'generic_perform_write+170 a_ops' Added new event: probe:generic_perform_write (on generic_perform_write+170 with a_ops) Signed-off-by: He Kuang <hekuang@huawei.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1431336304-16863-2-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
154 lines
4.8 KiB
C
154 lines
4.8 KiB
C
#ifndef _PROBE_EVENT_H
|
|
#define _PROBE_EVENT_H
|
|
|
|
#include <stdbool.h>
|
|
#include "intlist.h"
|
|
#include "strlist.h"
|
|
#include "strfilter.h"
|
|
|
|
/* Probe related configurations */
|
|
struct probe_conf {
|
|
bool show_ext_vars;
|
|
bool show_location_range;
|
|
bool force_add;
|
|
bool no_inlines;
|
|
int max_probes;
|
|
};
|
|
extern struct probe_conf probe_conf;
|
|
extern bool probe_event_dry_run;
|
|
|
|
/* kprobe-tracer and uprobe-tracer tracing point */
|
|
struct probe_trace_point {
|
|
char *realname; /* function real name (if needed) */
|
|
char *symbol; /* Base symbol */
|
|
char *module; /* Module name */
|
|
unsigned long offset; /* Offset from symbol */
|
|
unsigned long address; /* Actual address of the trace point */
|
|
bool retprobe; /* Return probe flag */
|
|
};
|
|
|
|
/* probe-tracer tracing argument referencing offset */
|
|
struct probe_trace_arg_ref {
|
|
struct probe_trace_arg_ref *next; /* Next reference */
|
|
long offset; /* Offset value */
|
|
};
|
|
|
|
/* kprobe-tracer and uprobe-tracer tracing argument */
|
|
struct probe_trace_arg {
|
|
char *name; /* Argument name */
|
|
char *value; /* Base value */
|
|
char *type; /* Type name */
|
|
struct probe_trace_arg_ref *ref; /* Referencing offset */
|
|
};
|
|
|
|
/* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
|
|
struct probe_trace_event {
|
|
char *event; /* Event name */
|
|
char *group; /* Group name */
|
|
struct probe_trace_point point; /* Trace point */
|
|
int nargs; /* Number of args */
|
|
bool uprobes; /* uprobes only */
|
|
struct probe_trace_arg *args; /* Arguments */
|
|
};
|
|
|
|
/* Perf probe probing point */
|
|
struct perf_probe_point {
|
|
char *file; /* File path */
|
|
char *function; /* Function name */
|
|
int line; /* Line number */
|
|
bool retprobe; /* Return probe flag */
|
|
char *lazy_line; /* Lazy matching pattern */
|
|
unsigned long offset; /* Offset from function entry */
|
|
};
|
|
|
|
/* Perf probe probing argument field chain */
|
|
struct perf_probe_arg_field {
|
|
struct perf_probe_arg_field *next; /* Next field */
|
|
char *name; /* Name of the field */
|
|
long index; /* Array index number */
|
|
bool ref; /* Referencing flag */
|
|
};
|
|
|
|
/* Perf probe probing argument */
|
|
struct perf_probe_arg {
|
|
char *name; /* Argument name */
|
|
char *var; /* Variable name */
|
|
char *type; /* Type name */
|
|
struct perf_probe_arg_field *field; /* Structure fields */
|
|
};
|
|
|
|
/* Perf probe probing event (point + arg) */
|
|
struct perf_probe_event {
|
|
char *event; /* Event name */
|
|
char *group; /* Group name */
|
|
struct perf_probe_point point; /* Probe point */
|
|
int nargs; /* Number of arguments */
|
|
bool uprobes; /* Uprobe event flag */
|
|
char *target; /* Target binary */
|
|
struct perf_probe_arg *args; /* Arguments */
|
|
};
|
|
|
|
/* Line range */
|
|
struct line_range {
|
|
char *file; /* File name */
|
|
char *function; /* Function name */
|
|
int start; /* Start line number */
|
|
int end; /* End line number */
|
|
int offset; /* Start line offset */
|
|
char *path; /* Real path name */
|
|
char *comp_dir; /* Compile directory */
|
|
struct intlist *line_list; /* Visible lines */
|
|
};
|
|
|
|
/* List of variables */
|
|
struct variable_list {
|
|
struct probe_trace_point point; /* Actual probepoint */
|
|
struct strlist *vars; /* Available variables */
|
|
};
|
|
|
|
/* Command string to events */
|
|
extern int parse_perf_probe_command(const char *cmd,
|
|
struct perf_probe_event *pev);
|
|
|
|
/* Events to command string */
|
|
extern char *synthesize_perf_probe_command(struct perf_probe_event *pev);
|
|
extern char *synthesize_probe_trace_command(struct probe_trace_event *tev);
|
|
extern int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf,
|
|
size_t len);
|
|
|
|
/* Check the perf_probe_event needs debuginfo */
|
|
extern bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
|
|
|
|
/* Release event contents */
|
|
extern void clear_perf_probe_event(struct perf_probe_event *pev);
|
|
|
|
/* Command string to line-range */
|
|
extern int parse_line_range_desc(const char *cmd, struct line_range *lr);
|
|
|
|
/* Release line range members */
|
|
extern void line_range__clear(struct line_range *lr);
|
|
|
|
/* Initialize line range */
|
|
extern int line_range__init(struct line_range *lr);
|
|
|
|
/* Internal use: Return kernel/module path */
|
|
extern const char *kernel_get_module_path(const char *module);
|
|
|
|
extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
|
|
extern int del_perf_probe_events(struct strfilter *filter);
|
|
extern int show_perf_probe_events(struct strfilter *filter);
|
|
extern int show_line_range(struct line_range *lr, const char *module,
|
|
bool user);
|
|
extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
|
|
struct strfilter *filter);
|
|
extern int show_available_funcs(const char *module, struct strfilter *filter,
|
|
bool user);
|
|
bool arch__prefers_symtab(void);
|
|
void arch__fix_tev_from_maps(struct perf_probe_event *pev,
|
|
struct probe_trace_event *tev, struct map *map);
|
|
|
|
/* Maximum index number of event-name postfix */
|
|
#define MAX_EVENT_INDEX 1024
|
|
|
|
#endif /*_PROBE_EVENT_H */
|