perf symbols: Cache /proc/kallsyms files by build-id

So that when we don't have a vmlinux handy we can store the
kallsyms for later use by 'perf report'.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1263501006-14185-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 24ec5be..0e9820a 100644 (file)
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -245,7 +245,7 @@ int event__synthesize_kernel_mmap(event__handler_t process,
         */
        struct process_symbol_args args = { .name = symbol_name, };
 
-       if (kallsyms__parse(&args, find_symbol_cb) <= 0)
+       if (kallsyms__parse("/proc/kallsyms", &args, find_symbol_cb) <= 0)
                return -ENOENT;
 
        size = snprintf(ev.mmap.filename, sizeof(ev.mmap.filename),

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index b31e0ae..1b65fed 100644 (file)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -237,11 +237,13 @@ static int dso__cache_build_id(struct dso *self, const char *debugdir)
        char *filename = malloc(size),
             *linkname = malloc(size), *targetname, *sbuild_id;
        int len, err = -1;
+       bool is_kallsyms = self->kernel && self->long_name[0] != '/';
 
        if (filename == NULL || linkname == NULL)
                goto out_free;
 
-       len = snprintf(filename, size, "%s%s", debugdir, self->long_name);
+       len = snprintf(filename, size, "%s%s%s",
+                      debugdir, is_kallsyms ? "/" : "", self->long_name);
        if (mkdir_p(filename, 0755))
                goto out_free;
 
@@ -249,9 +251,14 @@ static int dso__cache_build_id(struct dso *self, const char *debugdir)
        sbuild_id = filename + len;
        build_id__sprintf(self->build_id, sizeof(self->build_id), sbuild_id);
 
-       if (access(filename, F_OK) && link(self->long_name, filename) &&
-           copyfile(self->long_name, filename))
-               goto out_free;
+       if (access(filename, F_OK)) {
+               if (is_kallsyms) {
+                        if (copyfile("/proc/kallsyms", filename))
+                               goto out_free;
+               } else if (link(self->long_name, filename) &&
+                          copyfile(self->long_name, filename))
+                       goto out_free;
+       }
 
        len = snprintf(linkname, size, "%s/.build-id/%.2s",
                       debugdir, sbuild_id);

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 71d23e1..ae61e9f 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -383,13 +383,14 @@ size_t dso__fprintf(struct dso *self, enum map_type type, FILE *fp)
        return ret;
 }
 
-int kallsyms__parse(void *arg, int (*process_symbol)(void *arg, const char *name,
+int kallsyms__parse(const char *filename, void *arg,
+                   int (*process_symbol)(void *arg, const char *name,
                                                     char type, u64 start))
 {
        char *line = NULL;
        size_t n;
        int err = 0;
-       FILE *file = fopen("/proc/kallsyms", "r");
+       FILE *file = fopen(filename, "r");
 
        if (file == NULL)
                goto out_failure;
@@ -466,10 +467,11 @@ static int map__process_kallsym_symbol(void *arg, const char *name,
  * so that we can in the next step set the symbol ->end address and then
  * call kernel_maps__split_kallsyms.
  */
-static int dso__load_all_kallsyms(struct dso *self, struct map *map)
+static int dso__load_all_kallsyms(struct dso *self, const char *filename,
+                                 struct map *map)
 {
        struct process_kallsyms_args args = { .map = map, .dso = self, };
-       return kallsyms__parse(&args, map__process_kallsym_symbol);
+       return kallsyms__parse(filename, &args, map__process_kallsym_symbol);
 }
 
 /*
@@ -556,10 +558,10 @@ discard_symbol:           rb_erase(&pos->rb_node, root);
 }
 
 
-static int dso__load_kallsyms(struct dso *self, struct map *map,
+static int dso__load_kallsyms(struct dso *self, const char *filename, struct map *map,
                              struct perf_session *session, symbol_filter_t filter)
 {
-       if (dso__load_all_kallsyms(self, map) < 0)
+       if (dso__load_all_kallsyms(self, filename, map) < 0)
                return -1;
 
        symbols__fixup_end(&self->symbols[map->type]);
@@ -1580,7 +1582,8 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map,
                                struct perf_session *session, symbol_filter_t filter)
 {
        int err;
-       bool is_kallsyms;
+       const char *kallsyms_filename = NULL;
+       char *kallsyms_allocated_filename = NULL;
 
        if (vmlinux_path != NULL) {
                int i;
@@ -1606,19 +1609,37 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map,
         */
        if (self->has_build_id) {
                u8 kallsyms_build_id[BUILD_ID_SIZE];
+               char sbuild_id[BUILD_ID_SIZE * 2 + 1];
 
                if (sysfs__read_build_id("/sys/kernel/notes", kallsyms_build_id,
                                         sizeof(kallsyms_build_id)) == 0) {
-                       is_kallsyms = dso__build_id_equal(self, kallsyms_build_id);
-                       if (is_kallsyms)
+                       if (dso__build_id_equal(self, kallsyms_build_id)) {
+                               kallsyms_filename = "/proc/kallsyms";
                                goto do_kallsyms;
+                       }
                }
+
+               build_id__sprintf(self->build_id, sizeof(self->build_id),
+                                 sbuild_id);
+
+               if (asprintf(&kallsyms_allocated_filename,
+                            "%s/.debug/[kernel.kallsyms]/%s",
+                            getenv("HOME"), sbuild_id) != -1) {
+                       if (access(kallsyms_filename, F_OK)) {
+                               kallsyms_filename = kallsyms_allocated_filename;
+                               goto do_kallsyms;
+                       }
+                       free(kallsyms_allocated_filename);
+                       kallsyms_allocated_filename = NULL;
+               }
+
                goto do_vmlinux;
        }
 
-       is_kallsyms = self->long_name[0] == '[';
-       if (is_kallsyms)
+       if (self->long_name[0] == '[') {
+               kallsyms_filename = "/proc/kallsyms";
                goto do_kallsyms;
+       }
 
 do_vmlinux:
        err = dso__load_vmlinux(self, map, session, self->long_name, filter);
@@ -1629,9 +1650,10 @@ do_vmlinux:
                pr_info("The file %s cannot be used, "
                        "trying to use /proc/kallsyms...", self->long_name);
 do_kallsyms:
-               err = dso__load_kallsyms(self, map, session, filter);
-               if (err > 0 && !is_kallsyms)
+               err = dso__load_kallsyms(self, kallsyms_filename, map, session, filter);
+               if (err > 0 && kallsyms_filename == NULL)
                         dso__set_long_name(self, strdup("[kernel.kallsyms]"));
+               free(kallsyms_allocated_filename);
        }
 
        if (err > 0) {

diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 594156e..36b7c71 100644 (file)
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -144,8 +144,9 @@ int filename__read_build_id(const char *filename, void *bf, size_t size);
 int sysfs__read_build_id(const char *filename, void *bf, size_t size);
 bool dsos__read_build_ids(void);
 int build_id__sprintf(u8 *self, int len, char *bf);
-int kallsyms__parse(void *arg, int (*process_symbol)(void *arg, const char *name,
-                                                    char type, u64 start));
+int kallsyms__parse(const char *filename, void *arg,
+                   int (*process_symbol)(void *arg, const char *name,
+                                         char type, u64 start));
 
 int symbol__init(void);
 bool symbol_type__is_a(char symbol_type, enum map_type map_type);

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index f3c0798..f068584 100644 (file)
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -32,6 +32,33 @@ int mkdir_p(char *path, mode_t mode)
        return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
 }
 
+static int slow_copyfile(const char *from, const char *to)
+{
+       int err = 0;
+       char *line = NULL;
+       size_t n;
+       FILE *from_fp = fopen(from, "r"), *to_fp;
+
+       if (from_fp == NULL)
+               goto out;
+
+       to_fp = fopen(to, "w");
+       if (to_fp == NULL)
+               goto out_fclose_from;
+
+       while (getline(&line, &n, from_fp) > 0)
+               if (fputs(line, to_fp) == EOF)
+                       goto out_fclose_to;
+       err = 0;
+out_fclose_to:
+       fclose(to_fp);
+       free(line);
+out_fclose_from:
+       fclose(from_fp);
+out:
+       return err;
+}
+
 int copyfile(const char *from, const char *to)
 {
        int fromfd, tofd;
@@ -42,6 +69,9 @@ int copyfile(const char *from, const char *to)
        if (stat(from, &st))
                goto out;
 
+       if (st.st_size == 0) /* /proc? do it slowly... */
+               return slow_copyfile(from, to);
+
        fromfd = open(from, O_RDONLY);
        if (fromfd < 0)
                goto out;