[PATCH perf/core 06/10] perf probe: Search SDT/cached event from all probe caches

Masami Hiramatsu
2016-07-12T10:05:38Z

Search SDT/cached event from all probe caches if user doesn't
pass any binary. With this, we don't have to specify target
binary for SDT and named cached events (which start with %).

E.g. without this, a target binary must be passed with -x.

# perf probe -x /usr/lib64/libc-2.20.so -a %sdt_libc:\*

With this change, we don't need it anymore.

# perf probe -a %sdt_libc:\*

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes from v10:
- Splitted from "perf probe: Allow wildcard for cached events"
---
tools/perf/util/probe-event.c | 105 ++++++++++++++++++++++++++++++++++-------
1 file changed, 86 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 1aeac09..679aa6b 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2557,41 +2557,60 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
return 0;
}

-static int __add_probe_trace_events(struct perf_probe_event *pev,
- struct probe_trace_event *tevs,
- int ntevs, bool allow_suffix)
+static int __open_probe_file_and_namelist(bool uprobe,
+ struct strlist **namelist)
{
- int i, fd, ret;
- struct probe_trace_event *tev = NULL;
- struct probe_cache *cache = NULL;
- struct strlist *namelist;
+ int fd;

- fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
+ fd = probe_file__open(PF_FL_RW | (uprobe ? PF_FL_UPROBE : 0));
if (fd < 0)
return fd;

/* Get current event names */
- namelist = probe_file__get_namelist(fd);
- if (!namelist) {
+ *namelist = probe_file__get_namelist(fd);
+ if (!(*namelist)) {
pr_debug("Failed to get current event list.\n");
- ret = -ENOMEM;
- goto close_out;
+ close(fd);
+ return -ENOMEM;
}
+ return fd;
+}
+
+static int __add_probe_trace_events(struct perf_probe_event *pev,
+ struct probe_trace_event *tevs,
+ int ntevs, bool allow_suffix)
+{
+ int i, fd[2] = {-1, -1}, up, ret;
+ struct probe_trace_event *tev = NULL;
+ struct probe_cache *cache = NULL;
+ struct strlist *namelist[2] = {NULL, NULL};
+
+ up = pev->uprobes ? 1 : 0;
+ fd[up] = __open_probe_file_and_namelist(up, &namelist[up]);
+ if (fd[up] < 0)
+ return fd[up];

ret = 0;
for (i = 0; i < ntevs; i++) {
tev = &tevs[i];
+ up = tev->uprobes ? 1 : 0;
+ if (fd[up] == -1) { /* Open the kprobe/uprobe_events */
+ fd[up] = __open_probe_file_and_namelist(up,
+ &namelist[up]);
+ if (fd[up] < 0)
+ goto close_out;
+ }
/* Skip if the symbol is out of .text or blacklisted */
if (!tev->point.symbol && !pev->uprobes)
continue;

/* Set new name for tev (and update namelist) */
- ret = probe_trace_event__set_name(tev, pev, namelist,
+ ret = probe_trace_event__set_name(tev, pev, namelist[up],
allow_suffix);
if (ret < 0)
break;

- ret = probe_file__add_event(fd, tev);
+ ret = probe_file__add_event(fd[up], tev);
if (ret < 0)
break;

@@ -2614,9 +2633,12 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
probe_cache__delete(cache);
}

- strlist__delete(namelist);
close_out:
- close(fd);
+ for (up = 0; up < 2; up++) {
+ strlist__delete(namelist[up]);
+ if (fd[up] >= 0)
+ close(fd[up]);
+ }
return ret;
}

@@ -2989,6 +3011,48 @@ static int find_cached_events(struct perf_probe_event *pev,
return ret;
}

+/* Try to find probe_trace_event from all probe caches */
+static int find_cached_events_all(struct perf_probe_event *pev,
+ struct probe_trace_event **tevs)
+{
+ struct probe_trace_event *tmp_tevs = NULL;
+ struct strlist *bidlist;
+ struct str_node *nd;
+ char *pathname;
+ int ntevs = 0;
+ int ret;
+
+ /* Get the buildid list of all valid caches */
+ bidlist = build_id_cache__list_all(true);
+ if (!bidlist) {
+ ret = -errno;
+ pr_debug("Failed to get buildids: %d\n", ret);
+ return ret;
+ }
+
+ ret = 0;
+ strlist__for_each_entry(nd, bidlist) {
+ pathname = build_id_cache__origname(nd->s);
+ ret = find_cached_events(pev, &tmp_tevs, pathname);
+ /* In the case of cnt == 0, we just skip it */
+ if (ret > 0)
+ ret = concat_probe_trace_events(tevs, &ntevs,
+ &tmp_tevs, ret);
+ free(pathname);
+ if (ret < 0)
+ break;
+ }
+ strlist__delete(bidlist);
+
+ if (ret < 0) {
+ clear_probe_trace_events(*tevs, ntevs);
+ zfree(tevs);
+ } else
+ ret = ntevs;
+
+ return ret;
+}
+
static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
struct probe_trace_event **tevs)
{
@@ -2998,10 +3062,13 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
struct str_node *node;
int ret, i;

- if (pev->sdt)
+ if (pev->sdt) {
/* For SDT/cached events, we use special search functions */
- return find_cached_events(pev, tevs, pev->target);
-
+ if (!pev->target)
+ return find_cached_events_all(pev, tevs);
+ else
+ return find_cached_events(pev, tevs, pev->target);
+ }
cache = probe_cache__new(pev->target);
if (!cache)
return 0;