depmod: cache info_list in struct mod

The overall goal is to coalesce the accesses to a file that is the
backend of a module. This commit addresses the calls to
kmod_module_get_info(). Calling it earlier, while we are iterating the
modules allows us to free the struct kmod of each module much sooner. We
are still not freeing it since there are other places that must be
refactored first.

A nice side effect is that this commit reduces in ~33% the calls to
malloc(), giving a speedup of ~6% for cold caches (reproduced on only 1
laptop).

1 files changed, 22 insertions, 32 deletions

diff --git a/tools/depmod.c b/tools/depmod.c
index fcdb880..5423bad 100644
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -996,6 +996,7 @@ struct mod {
 	const char *path;
 	const char *relpath; /* path relative to '$ROOT/lib/modules/$VER/' */
 	char *uncrelpath; /* same as relpath but ending in .ko */
+	struct kmod_list *info_list;
 	struct array deps; /* struct symbol */
 	size_t baselen; /* points to start of basename/filename */
 	size_t modnamelen;
@@ -1028,6 +1029,7 @@ static void mod_free(struct mod *mod)
 	DBG("free %p kmod=%p, path=%s\n", mod, mod->kmod, mod->path);
 	array_free_array(&mod->deps);
 	kmod_module_unref(mod->kmod);
+	kmod_module_info_free_list(mod->info_list);
 	free(mod->uncrelpath);
 	free(mod);
 }
@@ -1541,16 +1543,16 @@ static struct symbol *depmod_symbol_find(const struct depmod *depmod,
 	return hash_find(depmod->symbols, name);
 }
 
-static int depmod_load_symbols(struct depmod *depmod)
+static int depmod_load_symbols_and_info(struct depmod *depmod)
 {
-	const struct mod **itr, **itr_end;
+	struct mod **itr, **itr_end;
 
 	DBG("load symbols (%zd modules)\n", depmod->modules.count);
 
-	itr = (const struct mod **)depmod->modules.array;
+	itr = (struct mod **)depmod->modules.array;
 	itr_end = itr + depmod->modules.count;
 	for (; itr < itr_end; itr++) {
-		const struct mod *mod = *itr;
+		struct mod *mod = *itr;
 		struct kmod_list *l, *list = NULL;
 		int err = kmod_module_get_symbols(mod->kmod, &list);
 		if (err < 0) {
@@ -1559,7 +1561,7 @@ static int depmod_load_symbols(struct depmod *depmod)
 			else
 				ERR("failed to load symbols from %s: %s\n",
 						mod->path, strerror(-err));
-			continue;
+			goto load_info;
 		}
 		kmod_list_foreach(l, list) {
 			const char *name = kmod_module_symbol_get_symbol(l);
@@ -1567,6 +1569,9 @@ static int depmod_load_symbols(struct depmod *depmod)
 			depmod_symbol_add(depmod, name, crc, mod);
 		}
 		kmod_module_symbols_free_list(list);
+
+load_info:
+		kmod_module_get_info(mod->kmod, &mod->info_list);
 	}
 
 	DBG("loaded symbols (%zd modules, %zd symbols)\n",
@@ -1742,7 +1747,7 @@ static int depmod_load(struct depmod *depmod)
 {
 	int err;
 
-	err = depmod_load_symbols(depmod);
+	err = depmod_load_symbols_and_info(depmod);
 	if (err < 0)
 		return err;
 
@@ -1962,11 +1967,9 @@ static int output_aliases(struct depmod *depmod, FILE *out)
 
 	for (i = 0; i < depmod->modules.count; i++) {
 		const struct mod *mod = depmod->modules.array[i];
-		struct kmod_list *l, *list = NULL;
-		int r = kmod_module_get_info(mod->kmod, &list);
-		if (r < 0 || list == NULL)
-			continue;
-		kmod_list_foreach(l, list) {
+		struct kmod_list *l;
+
+		kmod_list_foreach(l, mod->info_list) {
 			const char *key = kmod_module_info_get_key(l);
 			const char *value = kmod_module_info_get_value(l);
 
@@ -1976,7 +1979,6 @@ static int output_aliases(struct depmod *depmod, FILE *out)
 			fprintf(out, "alias %s %s\n",
 				value, kmod_module_get_name(mod->kmod));
 		}
-		kmod_module_info_free_list(list);
 	}
 
 	return 0;
@@ -1997,11 +1999,9 @@ static int output_aliases_bin(struct depmod *depmod, FILE *out)
 
 	for (i = 0; i < depmod->modules.count; i++) {
 		const struct mod *mod = depmod->modules.array[i];
-		struct kmod_list *l, *list = NULL;
-		int r = kmod_module_get_info(mod->kmod, &list);
-		if (r < 0 || list == NULL)
-			continue;
-		kmod_list_foreach(l, list) {
+		struct kmod_list *l;
+
+		kmod_list_foreach(l, mod->info_list) {
 			const char *key = kmod_module_info_get_key(l);
 			const char *value = kmod_module_info_get_value(l);
 			const char *modname, *alias;
@@ -2021,7 +2021,6 @@ static int output_aliases_bin(struct depmod *depmod, FILE *out)
 				WRN("duplicate module alias:\n%s %s\n",
 				    alias, modname);
 		}
-		kmod_module_info_free_list(list);
 	}
 
 	index_write(idx, out);
@@ -2040,11 +2039,9 @@ static int output_softdeps(struct depmod *depmod, FILE *out)
 
 	for (i = 0; i < depmod->modules.count; i++) {
 		const struct mod *mod = depmod->modules.array[i];
-		struct kmod_list *l, *list = NULL;
-		int r = kmod_module_get_info(mod->kmod, &list);
-		if (r < 0 || list == NULL)
-			continue;
-		kmod_list_foreach(l, list) {
+		struct kmod_list *l;
+
+		kmod_list_foreach(l, mod->info_list) {
 			const char *key = kmod_module_info_get_key(l);
 			const char *value = kmod_module_info_get_value(l);
 
@@ -2054,7 +2051,6 @@ static int output_softdeps(struct depmod *depmod, FILE *out)
 			fprintf(out, "softdep %s %s\n",
 				kmod_module_get_name(mod->kmod), value);
 		}
-		kmod_module_info_free_list(list);
 	}
 
 	return 0;
@@ -2169,17 +2165,12 @@ static int output_devname(struct depmod *depmod, FILE *out)
 
 	for (i = 0; i < depmod->modules.count; i++) {
 		const struct mod *mod = depmod->modules.array[i];
-		struct kmod_list *l, *list = NULL;
+		struct kmod_list *l;
 		const char *devname = NULL;
 		char type = '\0';
 		unsigned int major = 0, minor = 0;
-		int r;
 
-		r = kmod_module_get_info(mod->kmod, &list);
-		if (r < 0 || list == NULL)
-			continue;
-
-		kmod_list_foreach(l, list) {
+		kmod_list_foreach(l, mod->info_list) {
 			const char *key = kmod_module_info_get_key(l);
 			const char *value = kmod_module_info_get_value(l);
 			unsigned int maj, min;
@@ -2208,7 +2199,6 @@ static int output_devname(struct depmod *depmod, FILE *out)
 				break;
 			}
 		}
-		kmod_module_info_free_list(list);
 	}
 
 	return 0;