perf symbols: Do lazy symtab loading for the kernel & modules too

Just like we do with the other DSOs. This also simplifies the
kernel_maps setup process, now all that the tools need to do is
to call kernel_maps__init and the maps for the modules and
kernel will be created, then, later, when
kernel_maps__find_symbol() is used, it will also call
maps__find_symbol that already checks if the symtab was loaded,
loading it if needed.

Now if one does 'perf top --hide_kernel_symbols' we won't pay
the price of loading the (many) symbols in /proc/kallsyms or
vmlinux.

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: <1258757489-5978-4-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-annotate.c

@@ -157,7 +157,7 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 
 	if (event->header.misc & PERF_RECORD_MISC_KERNEL) {
 		level = 'k';
-		sym = kernel_maps__find_symbol(ip, &map);
+		sym = kernel_maps__find_symbol(ip, &map, symbol_filter);
 		dump_printf(" ...... dso: %s\n",
 			    map ? map->dso->long_name : "<not found>");
 	} else if (event->header.misc & PERF_RECORD_MISC_USER) {
@@ -637,9 +637,9 @@ static int __cmd_annotate(void)
 		exit(0);
 	}
 
-	if (load_kernel(symbol_filter, use_modules) < 0) {
-		perror("failed to load kernel symbols");
-		return EXIT_FAILURE;
+	if (kernel_maps__init(use_modules) < 0) {
+		pr_err("failed to create kernel maps for symbol resolution\b");
+		return -1;
 	}
 
 remap:

tools/perf/builtin-report.c

@@ -449,7 +449,7 @@ resolve_symbol(struct thread *thread, struct map **mapp, u64 *ipp)
 		 * trick of looking in the whole kernel symbol list.
 		 */
 		if ((long long)ip < 0)
-			return kernel_maps__find_symbol(ip, mapp);
+			return kernel_maps__find_symbol(ip, mapp, NULL);
 	}
 	dump_printf(" ...... dso: %s\n",
 		    map ? map->dso->long_name : "<not found>");
@@ -496,7 +496,7 @@ static struct symbol **resolve_callchain(struct thread *thread, struct map *map,
 		case PERF_CONTEXT_HV:
 			break;
 		case PERF_CONTEXT_KERNEL:
-			sym = kernel_maps__find_symbol(ip, &map);
+			sym = kernel_maps__find_symbol(ip, &map, NULL);
 			break;
 		default:
 			sym = resolve_symbol(thread, &map, &ip);
@@ -716,7 +716,7 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 
 	if (cpumode == PERF_RECORD_MISC_KERNEL) {
 		level = 'k';
-		sym = kernel_maps__find_symbol(ip, &map);
+		sym = kernel_maps__find_symbol(ip, &map, NULL);
 		dump_printf(" ...... dso: %s\n",
 			    map ? map->dso->long_name : "<not found>");
 	} else if (cpumode == PERF_RECORD_MISC_USER) {

tools/perf/builtin-top.c

@@ -830,6 +830,8 @@ static void handle_keypress(int c)
 		case 'q':
 		case 'Q':
 			printf("exiting.\n");
+			if (dump_symtab)
+				dsos__fprintf(stderr);
 			exit(0);
 		case 's':
 			prompt_symbol(&sym_filter_entry, "Enter details symbol");
@@ -946,30 +948,6 @@ static int symbol_filter(struct map *map, struct symbol *sym)
 	return 0;
 }
 
-static int parse_symbols(void)
-{
-	struct dso *kernel = dsos__load_kernel();
-
-	if (kernel == NULL)
-		return -1;
-
-	if (dsos__load_modules() < 0)
-		pr_debug("Couldn't read the complete list of modules, "
-			 "continuing...\n");
-
-	if (dsos__load_modules_sym(symbol_filter) < 0)
-		pr_warning("Failed to read module symbols, continuing...\n");
-
-	if (dso__load_kernel_sym(kernel, symbol_filter, 1) <= 0)
-		pr_debug("Couldn't read the complete list of kernel symbols, "
-			 "continuing...\n");
-
-	if (dump_symtab)
-		dsos__fprintf(stderr);
-
-	return 0;
-}
-
 static void event__process_sample(const event_t *self, int counter)
 {
 	u64 ip = self->ip.ip;
@@ -1012,7 +990,7 @@ static void event__process_sample(const event_t *self, int counter)
 		if (hide_kernel_symbols)
 			return;
 
-		sym = kernel_maps__find_symbol(ip, &map);
+		sym = kernel_maps__find_symbol(ip, &map, symbol_filter);
 		if (sym == NULL)
 			return;
 		break;
@@ -1339,7 +1317,7 @@ static const struct option options[] = {
 
 int cmd_top(int argc, const char **argv, const char *prefix __used)
 {
-	int counter;
+	int counter, err;
 
 	page_size = sysconf(_SC_PAGE_SIZE);
 
@@ -1363,10 +1341,11 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
 	if (delay_secs < 1)
 		delay_secs = 1;
 
-	parse_symbols();
+	err = kernel_maps__init(true);
+	if (err < 0)
+		return err;
 	parse_source(sym_filter_entry);
 
-
 	/*
 	 * User specified count overrides default frequency.
 	 */

tools/perf/util/data_map.c

@@ -171,8 +171,8 @@ int mmap_dispatch_perf_file(struct perf_header **pheader,
 		goto out_delete;
 
 	err = -ENOMEM;
-	if (load_kernel(NULL, 1) < 0) {
-		pr_err("failed to load kernel symbols\n");
+	if (kernel_maps__init(true) < 0) {
+		pr_err("failed to setup the kernel maps to resolve symbols\n");
 		goto out_delete;
 	}
 

tools/perf/util/event.h

@@ -115,10 +115,13 @@ typedef int (*symbol_filter_t)(struct map *map, struct symbol *sym);
 void map__init(struct map *self, u64 start, u64 end, u64 pgoff,
 	       struct dso *dso);
 struct map *map__new(struct mmap_event *event, char *cwd, int cwdlen);
+void map__delete(struct map *self);
 struct map *map__clone(struct map *self);
 int map__overlap(struct map *l, struct map *r);
 size_t map__fprintf(struct map *self, FILE *fp);
 struct symbol *map__find_symbol(struct map *self, u64 ip, symbol_filter_t filter);
+void map__fixup_start(struct map *self);
+void map__fixup_end(struct map *self);
 
 int event__synthesize_thread(pid_t pid, int (*process)(event_t *event));
 void event__synthesize_threads(int (*process)(event_t *event));

tools/perf/util/header.c

@@ -253,11 +253,11 @@ static int perf_header__adds_write(struct perf_header *self, int fd)
 
 		buildid_sec = &feat_sec[idx++];
 
-		dsos__load_kernel();
 		/*
-		 * Read the list of loaded modules with its build_ids
+		 * Read the kernel buildid nad the list of loaded modules with
+		 * its build_ids:
 		 */
-		dsos__load_modules();
+		kernel_maps__init(true);
 
 		/* Write build-ids */
 		buildid_sec->offset = lseek(fd, 0, SEEK_CUR);

tools/perf/util/map.c

@@ -75,6 +75,29 @@ struct map *map__new(struct mmap_event *event, char *cwd, int cwdlen)
 	return NULL;
 }
 
+void map__delete(struct map *self)
+{
+	free(self);
+}
+
+void map__fixup_start(struct map *self)
+{
+	struct rb_node *nd = rb_first(&self->dso->syms);
+	if (nd != NULL) {
+		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
+		self->start = sym->start;
+	}
+}
+
+void map__fixup_end(struct map *self)
+{
+	struct rb_node *nd = rb_last(&self->dso->syms);
+	if (nd != NULL) {
+		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
+		self->end = sym->end;
+	}
+}
+
 #define DSO__DELETED "(deleted)"
 
 struct symbol *