perf probe: Add --max-probes option

Add --max-probes option to change the maximum limit of
findable probe points per event, since inlined function can be
expanded into thousands of probe points. Default value is 128.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20100421195640.24664.62984.stgit@localhost6.localdomain6>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

6 files changed, 33 insertions, 17 deletions

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 63c25d304880..94a258c96a44 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -62,6 +62,9 @@ OPTIONS
         Dry run. With this option, --add and --del doesn't execute actual
         adding and removal operations.
 
+--max-probes::
+        Set the maximum number of probe points for an event. Default is 128.
+
 PROBE SYNTAX
 ------------
 Probe points are defined by following syntax.
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index c1e54035e8cf..61c6d70732c9 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -54,6 +54,7 @@ static struct {
         struct perf_probe_event events[MAX_PROBES];
         struct strlist *dellist;
         struct line_range line_range;
+        int max_probe_points;
 } params;
 
 
@@ -179,6 +180,8 @@ static const struct option options[] = {
                    "file", "vmlinux pathname"),
 #endif
         OPT__DRY_RUN(&probe_event_dry_run),
+        OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
+                 "Set how many probe points can be found for a probe."),
         OPT_END()
 };
 
@@ -200,6 +203,9 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
                 }
         }
 
+        if (params.max_probe_points == 0)
+                params.max_probe_points = MAX_PROBES;
+
         if ((!params.nevents && !params.dellist && !params.list_events &&
              !params.show_lines))
                 usage_with_options(probe_usage, options);
@@ -246,7 +252,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 
         if (params.nevents) {
                 ret = add_perf_probe_events(params.events, params.nevents,
-                                            params.force_add);
+                                            params.force_add,
+                                            params.max_probe_points);
                 if (ret < 0) {
                         pr_err("  Error: Failed to add events. (%d)\n", ret);
                         return ret;
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 5d3baec216e3..9ded38ced234 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -150,7 +150,8 @@ static int convert_to_perf_probe_point(struct kprobe_trace_point *tp,
 
 /* Try to find perf_probe_event with debuginfo */
 static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev,
-                                           struct kprobe_trace_event **tevs)
+                                           struct kprobe_trace_event **tevs,
+                                           int max_tevs)
 {
         bool need_dwarf = perf_probe_event_need_dwarf(pev);
         int fd, ntevs;
@@ -166,7 +167,7 @@ static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev,
         }
 
         /* Searching trace events corresponding to probe event */
-        ntevs = find_kprobe_trace_events(fd, pev, tevs);
+        ntevs = find_kprobe_trace_events(fd, pev, tevs, max_tevs);
         close(fd);
 
         if (ntevs > 0) {        /* Succeeded to find trace events */
@@ -318,7 +319,8 @@ static int convert_to_perf_probe_point(struct kprobe_trace_point *tp,
 }
 
 static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev,
-                                struct kprobe_trace_event **tevs __unused)
+                                struct kprobe_trace_event **tevs __unused,
+                                int max_tevs __unused)
 {
         if (perf_probe_event_need_dwarf(pev)) {
                 pr_warning("Debuginfo-analysis is not supported.\n");
@@ -1408,14 +1410,15 @@ static int __add_kprobe_trace_events(struct perf_probe_event *pev,
 }
 
 static int convert_to_kprobe_trace_events(struct perf_probe_event *pev,
-                                          struct kprobe_trace_event **tevs)
+                                          struct kprobe_trace_event **tevs,
+                                          int max_tevs)
 {
         struct symbol *sym;
         int ret = 0, i;
         struct kprobe_trace_event *tev;
 
         /* Convert perf_probe_event with debuginfo */
-        ret = try_to_find_kprobe_trace_events(pev, tevs);
+        ret = try_to_find_kprobe_trace_events(pev, tevs, max_tevs);
         if (ret != 0)
                 return ret;
 
@@ -1487,7 +1490,7 @@ struct __event_package {
 };
 
 int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
-                          bool force_add)
+                          bool force_add, int max_tevs)
 {
         int i, j, ret;
         struct __event_package *pkgs;
@@ -1506,7 +1509,7 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
                 pkgs[i].pev = &pevs[i];
                 /* Convert with or without debuginfo */
                 ret  = convert_to_kprobe_trace_events(pkgs[i].pev,
-                                                      &pkgs[i].tevs);
+                                                      &pkgs[i].tevs, max_tevs);
                 if (ret < 0)
                         goto end;
                 pkgs[i].ntevs = ret;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index e7ff0d02c0d4..e9db1a214ca4 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -115,8 +115,8 @@ extern void clear_kprobe_trace_event(struct kprobe_trace_event *tev);
 extern int parse_line_range_desc(const char *cmd, struct line_range *lr);
 
 
-extern int add_perf_probe_events(struct perf_probe_event *pevs, int ntevs,
-                                 bool force_add);
+extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
+                                 bool force_add, int max_probe_points);
 extern int del_perf_probe_events(struct strlist *dellist);
 extern int show_perf_probe_events(void);
 extern int show_line_range(struct line_range *lr);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 0d795bc3e1a8..562b1443e785 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -626,8 +626,9 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
         Dwarf_Attribute fb_attr;
         size_t nops;
 
-        if (pf->ntevs == MAX_PROBES) {
-                pr_warning("Too many( > %d) probe point found.\n", MAX_PROBES);
+        if (pf->ntevs == pf->max_tevs) {
+                pr_warning("Too many( > %d) probe point found.\n",
+                           pf->max_tevs);
                 return -ERANGE;
         }
         tev = &pf->tevs[pf->ntevs++];
@@ -932,9 +933,9 @@ static int find_probe_point_by_func(struct probe_finder *pf)
 
 /* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
 int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
-                             struct kprobe_trace_event **tevs)
+                             struct kprobe_trace_event **tevs, int max_tevs)
 {
-        struct probe_finder pf = {.pev = pev};
+        struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
         struct perf_probe_point *pp = &pev->point;
         Dwarf_Off off, noff;
         size_t cuhl;
@@ -942,7 +943,7 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
         Dwarf *dbg;
         int ret = 0;
 
-        pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * MAX_PROBES);
+        pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
         if (pf.tevs == NULL)
                 return -ENOMEM;
         *tevs = pf.tevs;
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 310ce897229c..66f1980e3855 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -18,7 +18,8 @@ static inline int is_c_varname(const char *name)
 #ifdef DWARF_SUPPORT
 /* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
 extern int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
-                                    struct kprobe_trace_event **tevs);
+                                    struct kprobe_trace_event **tevs,
+                                    int max_tevs);
 
 /* Find a perf_probe_point from debuginfo */
 extern int find_perf_probe_point(int fd, unsigned long addr,
@@ -32,7 +33,8 @@ extern int find_line_range(int fd, struct line_range *lr);
 struct probe_finder {
         struct perf_probe_event *pev;           /* Target probe event */
         struct kprobe_trace_event *tevs;        /* Result trace events */
-        int                     ntevs;          /* number of trace events */
+        int                     ntevs;          /* Number of trace events */
+        int                     max_tevs;       /* Max number of trace events */
 
         /* For function searching */
         int                     lno;            /* Line number */