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@intel.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1391004884-10334-6-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3c394bf16fa8cd86ce01d3d5852bab8a078f5ae4..af47531b82ecda73a9233b7c9aef27c70754666a 100644 (file)
--- 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 17476df5c7b2fe1494475f436c517ed14f63442a..b0f3ca850e9e8ffbf5c1e70b9f04215e545a71ae 100644 (file)
--- 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 66a0c03928635cf75c02c5d409f0777e7982c806..851fa06f4a427d47b2c2af5ee70e345fda643978 100644 (file)
--- 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,