lkml.org 
[lkml]   [2015]   [Sep]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] perf probe: Use existing routine to look for a kernel module by dso->short_name
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

We have map_groups__find_by_name() to look at the list of modules that
are in place for a given machine, so use it instead of traversing the
machine dso list, which also includes DSOs for userspace.

When merging the user and kernel DSO lists a bug was introduced where
'perf probe' stopped being able to add probes to modules using its short
name:

# perf probe -m usbnet --add usbnet_start_xmit
usbnet_start_xmit is out of .text, skip it.
Error: Failed to add events.
#

With this fix it works again:

# perf probe -m usbnet --add usbnet_start_xmit
Added new event:
probe:usbnet_start_xmit (on usbnet_start_xmit in usbnet)

You can now use it in all perf tools, such as:

perf record -e probe:usbnet_start_xmit -aR sleep 1
#

Reported-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Fixes: 3d39ac538629 ("perf machine: No need to have two DSOs lists")
Link: http://lkml.kernel.org/r/20150924015008.GE1897@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/probe-event.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index eb5f18b75402..c6f9af78f6f5 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -270,12 +270,13 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso)
int ret = 0;

if (module) {
- list_for_each_entry(dso, &host_machine->dsos.head, node) {
- if (!dso->kernel)
- continue;
- if (strncmp(dso->short_name + 1, module,
- dso->short_name_len - 2) == 0)
- goto found;
+ char module_name[128];
+
+ snprintf(module_name, sizeof(module_name), "[%s]", module);
+ map = map_groups__find_by_name(&host_machine->kmaps, MAP__FUNCTION, module_name);
+ if (map) {
+ dso = map->dso;
+ goto found;
}
pr_debug("Failed to find module %s.\n", module);
return -ENOENT;
--
2.1.0


\
 
 \ /
  Last update: 2015-09-25 17:41    [W:0.038 / U:10.756 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site