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perf machine: Reuse module path buffer

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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: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250222061015.303622-9-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Ian Rogers 2025-02-21 22:10:13 -08:00 committed by Namhyung Kim
parent d996c726a5
commit e7af194681
1 changed files with 23 additions and 11 deletions
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34
tools/perf/util/machine.c
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@ -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)
ret = maps__set_module_path(maps, path, &m);
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,