Commit 14a8fd7c authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt

perf probe: Support adding probes on offline kernel modules

Support adding probes on offline kernel modules. This enables
perf-probe to trace kernel-module init functions via perf-probe.
If user gives the path of module with -m option, perf-probe
expects the module is offline.
This feature works with --add, --funcs, and --vars.

E.g)
 # perf probe -m /lib/modules/`uname -r`/kernel/fs/btrfs/btrfs.ko \
   -a "extent_io_init:5 extent_state_cache"
 Add new events:
   probe:extent_io_init (on extent_io_init:5 with extent_state_cache)
   probe:extent_io_init_1 (on extent_io_init:5 with extent_state_cache)

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

         perf record -e probe:extent_io_init_1 -aR sleep 1
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20110627072751.6528.10230.stgit@fedora15Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 190b57fc
......@@ -34,9 +34,11 @@ OPTIONS
Specify vmlinux path which has debuginfo (Dwarf binary).
-m::
--module=MODNAME::
--module=MODNAME|PATH::
Specify module name in which perf-probe searches probe points
or lines.
or lines. If a path of module file is passed, perf-probe
treat it as an offline module (this means you can add a probe on
a module which has not been loaded yet).
-s::
--source=PATH::
......
......@@ -242,7 +242,8 @@ static const struct option options[] = {
OPT_STRING('s', "source", &symbol_conf.source_prefix,
"directory", "path to kernel source"),
OPT_STRING('m', "module", &params.target_module,
"modname", "target module name"),
"modname|path",
"target module name (for online) or path (for offline)"),
#endif
OPT__DRY_RUN(&probe_event_dry_run),
OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
......
......@@ -117,6 +117,10 @@ static struct map *kernel_get_module_map(const char *module)
struct rb_node *nd;
struct map_groups *grp = &machine.kmaps;
/* A file path -- this is an offline module */
if (module && strchr(module, '/'))
return machine__new_module(&machine, 0, module);
if (!module)
module = "kernel";
......@@ -173,12 +177,19 @@ const char *kernel_get_module_path(const char *module)
/* Open new debuginfo of given module */
static struct debuginfo *open_debuginfo(const char *module)
{
const char *path = kernel_get_module_path(module);
const char *path;
if (!path) {
pr_err("Failed to find path of %s module.\n",
module ?: "kernel");
return NULL;
/* A file path -- this is an offline module */
if (module && strchr(module, '/'))
path = module;
else {
path = kernel_get_module_path(module);
if (!path) {
pr_err("Failed to find path of %s module.\n",
module ?: "kernel");
return NULL;
}
}
return debuginfo__new(path);
}
......@@ -229,13 +240,36 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
int ntevs, const char *module)
{
int i;
int i, ret = 0;
char *tmp;
if (!module)
return 0;
tmp = strrchr(module, '/');
if (tmp) {
/* This is a module path -- get the module name */
module = strdup(tmp + 1);
if (!module)
return -ENOMEM;
tmp = strchr(module, '.');
if (tmp)
*tmp = '\0';
tmp = (char *)module; /* For free() */
}
for (i = 0; i < ntevs; i++) {
tevs[i].point.module = strdup(module);
if (!tevs[i].point.module)
return -ENOMEM;
if (!tevs[i].point.module) {
ret = -ENOMEM;
break;
}
}
return 0;
if (tmp)
free(tmp);
return ret;
}
/* Try to find perf_probe_event with debuginfo */
......
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