Commit e7af1946 authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
Browse files

perf machine: Reuse module path buffer 



Rather than copying the path and appending the directory entry in a
fresh path buffer, append to the path at the end of where it is for
the recursion level. This saves a PATH_MAX buffer per recursion level
and some unnecessary copying.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250222061015.303622-9-irogers@google.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent d996c726

tools/perf/util/machine.c

+23 −11
Original line number Diff line number Diff line
@@ -1338,22 +1338,23 @@ static int maps__set_module_path(struct maps *maps, const char *path, struct kmo 
	return 0;

}



static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, int depth)

static int maps__set_modules_path_dir(struct maps *maps, char *path, size_t path_size, int depth)

{

	struct io_dirent64 *dent;

	struct io_dir iod;

	size_t root_len = strlen(path);

	int ret = 0;



	io_dir__init(&iod, open(dir_name, O_CLOEXEC | O_DIRECTORY | O_RDONLY));

	io_dir__init(&iod, open(path, O_CLOEXEC | O_DIRECTORY | O_RDONLY));

	if (iod.dirfd < 0) {

		pr_debug("%s: cannot open %s dir\n", __func__, dir_name);

		pr_debug("%s: cannot open %s dir\n", __func__, path);

		return -1;

	}



	/* Bounds check, should never happen. */

	if (root_len >= path_size)

		return -1;

	path[root_len++] = '/';

	while ((dent = io_dir__readdir(&iod)) != NULL) {

		char path[PATH_MAX];



		path__join(path, sizeof(path), dir_name, dent->d_name);

		if (io_dir__is_dir(&iod, dent)) {

			if (!strcmp(dent->d_name, ".") ||

			    !strcmp(dent->d_name, ".."))
@@ -1366,7 +1367,12 @@ static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, i 
					continue;

			}



			ret = maps__set_modules_path_dir(maps, path, depth + 1);

			/* Bounds check, should never happen. */

			if (root_len + strlen(dent->d_name) >= path_size)

				continue;



			strcpy(path + root_len, dent->d_name);

			ret = maps__set_modules_path_dir(maps, path, path_size, depth + 1);

			if (ret < 0)

				goto out;

		} else {
@@ -1376,9 +1382,14 @@ static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, i 
			if (ret)

				goto out;



			if (m.kmod)

			if (m.kmod) {

				/* Bounds check, should never happen. */

				if (root_len + strlen(dent->d_name) < path_size) {

					strcpy(path + root_len, dent->d_name);

					ret = maps__set_module_path(maps, path, &m);



				}

			}

			zfree(&m.name);



			if (ret)
@@ -1404,7 +1415,8 @@ static int machine__set_modules_path(struct machine *machine) 
		 machine->root_dir, version);

	free(version);



	return maps__set_modules_path_dir(machine__kernel_maps(machine), modules_path, 0);

	return maps__set_modules_path_dir(machine__kernel_maps(machine),

					  modules_path, sizeof(modules_path), 0);

}

int __weak arch__fix_module_text_start(u64 *start __maybe_unused,

				u64 *size __maybe_unused,