From 14a8fd7ceea6915c613746203d6e9a2bf273f16c Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Mon, 27 Jun 2011 16:27:51 +0900 Subject: [PATCH] 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: Masami Hiramatsu Cc: Peter Zijlstra Cc: Frederic Weisbecker Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Link: http://lkml.kernel.org/r/20110627072751.6528.10230.stgit@fedora15 Signed-off-by: Steven Rostedt --- tools/perf/Documentation/perf-probe.txt | 6 ++- tools/perf/builtin-probe.c | 3 +- tools/perf/util/probe-event.c | 52 ++++++++++++++++++++----- 3 files changed, 49 insertions(+), 12 deletions(-) diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt index 02bafce4b341..2780d9ce48bf 100644 --- a/tools/perf/Documentation/perf-probe.txt +++ b/tools/perf/Documentation/perf-probe.txt @@ -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:: diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c index 2c0e64d0b4aa..5f2a5c7046df 100644 --- a/tools/perf/builtin-probe.c +++ b/tools/perf/builtin-probe.c @@ -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", ¶ms.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", ¶ms.max_probe_points, diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index ee3f41eec5c1..b82d54fa2c56 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -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 */ -- 2.20.1