[tip:perf/urgent] perf record: Get ref_reloc_sym from kernel map

From: tip-bot for Adrian Hunter
Date: Sun Feb 02 2014 - 03:56:26 EST


Commit-ID: 0ae617bedde062003fd70e566e9a2601e273ea0e
Gitweb: http://git.kernel.org/tip/0ae617bedde062003fd70e566e9a2601e273ea0e
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Wed, 29 Jan 2014 16:14:40 +0200
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 31 Jan 2014 17:21:50 -0300

perf record: Get ref_reloc_sym from kernel map

Now that ref_reloc_sym is set up when the kernel map is created,
'perf record' does not need to pass the symbol names to
perf_event__synthesize_kernel_mmap() which can read the values needed
from ref_reloc_sym directly.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1391004884-10334-6-git-send-email-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-record.c | 10 ++--------
tools/perf/util/event.c | 26 ++++++--------------------
tools/perf/util/event.h | 3 +--
3 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3c394bf..af47531 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -287,10 +287,7 @@ static void perf_event__synthesize_guest_os(struct machine *machine, void *data)
* have no _text sometimes.
*/
err = perf_event__synthesize_kernel_mmap(tool, process_synthesized_event,
- machine, "_text");
- if (err < 0)
- err = perf_event__synthesize_kernel_mmap(tool, process_synthesized_event,
- machine, "_stext");
+ machine);
if (err < 0)
pr_err("Couldn't record guest kernel [%d]'s reference"
" relocation symbol.\n", machine->pid);
@@ -457,10 +454,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
}

err = perf_event__synthesize_kernel_mmap(tool, process_synthesized_event,
- machine, "_text");
- if (err < 0)
- err = perf_event__synthesize_kernel_mmap(tool, process_synthesized_event,
- machine, "_stext");
+ machine);
if (err < 0)
pr_err("Couldn't record kernel reference relocation symbol\n"
"Symbol resolution may be skewed if relocation was used (e.g. kexec).\n"
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 17476df..b0f3ca8 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -483,15 +483,13 @@ u64 kallsyms__get_function_start(const char *kallsyms_filename,

int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
perf_event__handler_t process,
- struct machine *machine,
- const char *symbol_name)
+ struct machine *machine)
{
size_t size;
- const char *filename, *mmap_name;
- char path[PATH_MAX];
+ const char *mmap_name;
char name_buff[PATH_MAX];
struct map *map;
- u64 start;
+ struct kmap *kmap;
int err;
/*
* We should get this from /sys/kernel/sections/.text, but till that is
@@ -513,31 +511,19 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
* see kernel/perf_event.c __perf_event_mmap
*/
event->header.misc = PERF_RECORD_MISC_KERNEL;
- filename = "/proc/kallsyms";
} else {
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
- if (machine__is_default_guest(machine))
- filename = (char *) symbol_conf.default_guest_kallsyms;
- else {
- sprintf(path, "%s/proc/kallsyms", machine->root_dir);
- filename = path;
- }
- }
-
- start = kallsyms__get_function_start(filename, symbol_name);
- if (!start) {
- free(event);
- return -ENOENT;
}

map = machine->vmlinux_maps[MAP__FUNCTION];
+ kmap = map__kmap(map);
size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
- "%s%s", mmap_name, symbol_name) + 1;
+ "%s%s", mmap_name, kmap->ref_reloc_sym->name) + 1;
size = PERF_ALIGN(size, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
- event->mmap.pgoff = start;
+ event->mmap.pgoff = kmap->ref_reloc_sym->addr;
event->mmap.start = map->start;
event->mmap.len = map->end - event->mmap.start;
event->mmap.pid = machine->pid;
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 66a0c03..851fa06 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -214,8 +214,7 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
struct machine *machine, bool mmap_data);
int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
perf_event__handler_t process,
- struct machine *machine,
- const char *symbol_name);
+ struct machine *machine);

int perf_event__synthesize_modules(struct perf_tool *tool,
perf_event__handler_t process,
--
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