Messages in this thread Patch in this message | | | Date | Wed, 6 Dec 2023 21:04:31 -0800 | Subject | [PATCH v1 4/6] perf pmu: Switch to io_dir__readdir | From | Ian Rogers <> |
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Avoid DIR allocations when scanning sysfs by using io_dir for the readdir implementation, that allocates about 1kb on the stack.
Signed-off-by: Ian Rogers <irogers@google.com> --- tools/perf/util/pmu.c | 48 +++++++++++++++++------------------------- tools/perf/util/pmus.c | 30 ++++++++++---------------- 2 files changed, 30 insertions(+), 48 deletions(-)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 3c9609944a2f..cddb82123a1e 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -12,6 +12,7 @@ #include <stdbool.h> #include <dirent.h> #include <api/fs/fs.h> +#include <api/io_dir.h> #include <locale.h> #include <fnmatch.h> #include <math.h> @@ -184,19 +185,17 @@ static void perf_pmu_format__load(const struct perf_pmu *pmu, struct perf_pmu_fo */ int perf_pmu__format_parse(struct perf_pmu *pmu, int dirfd, bool eager_load) { - struct dirent *evt_ent; - DIR *format_dir; + struct io_dirent64 *evt_ent; + struct io_dir format_dir; int ret = 0; - format_dir = fdopendir(dirfd); - if (!format_dir) - return -EINVAL; + io_dir__init(&format_dir, dirfd); - while ((evt_ent = readdir(format_dir)) != NULL) { + while ((evt_ent = io_dir__readdir(&format_dir)) != NULL) { struct perf_pmu_format *format; char *name = evt_ent->d_name; - if (!strcmp(name, ".") || !strcmp(name, "..")) + if (io_dir__is_dir(&format_dir, evt_ent)) continue; format = perf_pmu__new_format(&pmu->format, name); @@ -223,7 +222,7 @@ int perf_pmu__format_parse(struct perf_pmu *pmu, int dirfd, bool eager_load) } } - closedir(format_dir); + close(format_dir.dirfd); return ret; } @@ -599,8 +598,8 @@ static inline bool pmu_alias_info_file(const char *name) static int pmu_aliases_parse(struct perf_pmu *pmu) { char path[PATH_MAX]; - struct dirent *evt_ent; - DIR *event_dir; + struct io_dirent64 *evt_ent; + struct io_dir event_dir; size_t len; int fd, dir_fd; @@ -615,13 +614,9 @@ static int pmu_aliases_parse(struct perf_pmu *pmu) return 0; } - event_dir = fdopendir(dir_fd); - if (!event_dir){ - close (dir_fd); - return -EINVAL; - } + io_dir__init(&event_dir, dir_fd); - while ((evt_ent = readdir(event_dir))) { + while ((evt_ent = io_dir__readdir(&event_dir))) { char *name = evt_ent->d_name; FILE *file; @@ -651,7 +646,6 @@ static int pmu_aliases_parse(struct perf_pmu *pmu) fclose(file); } - closedir(event_dir); close (dir_fd); pmu->sysfs_aliases_loaded = true; return 0; @@ -1883,10 +1877,9 @@ static void perf_pmu__del_caps(struct perf_pmu *pmu) */ int perf_pmu__caps_parse(struct perf_pmu *pmu) { - struct stat st; char caps_path[PATH_MAX]; - DIR *caps_dir; - struct dirent *evt_ent; + struct io_dir caps_dir; + struct io_dirent64 *evt_ent; int caps_fd; if (pmu->caps_initialized) @@ -1897,24 +1890,21 @@ int perf_pmu__caps_parse(struct perf_pmu *pmu) if (!perf_pmu__pathname_scnprintf(caps_path, sizeof(caps_path), pmu->name, "caps")) return -1; - if (stat(caps_path, &st) < 0) { + caps_fd = open(caps_path, O_CLOEXEC | O_DIRECTORY | O_RDONLY); + if (caps_fd == -1) { pmu->caps_initialized = true; return 0; /* no error if caps does not exist */ } - caps_dir = opendir(caps_path); - if (!caps_dir) - return -EINVAL; - - caps_fd = dirfd(caps_dir); + io_dir__init(&caps_dir, caps_fd); - while ((evt_ent = readdir(caps_dir)) != NULL) { + while ((evt_ent = io_dir__readdir(&caps_dir)) != NULL) { char *name = evt_ent->d_name; char value[128]; FILE *file; int fd; - if (!strcmp(name, ".") || !strcmp(name, "..")) + if (io_dir__is_dir(&caps_dir, evt_ent)) continue; fd = openat(caps_fd, name, O_RDONLY); @@ -1936,7 +1926,7 @@ int perf_pmu__caps_parse(struct perf_pmu *pmu) fclose(file); } - closedir(caps_dir); + close(caps_fd); pmu->caps_initialized = true; return pmu->nr_caps; diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index ce4931461741..65b23b98666b 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -3,10 +3,10 @@ #include <linux/list_sort.h> #include <linux/string.h> #include <linux/zalloc.h> +#include <api/io_dir.h> #include <subcmd/pager.h> #include <sys/types.h> #include <ctype.h> -#include <dirent.h> #include <pthread.h> #include <string.h> #include <unistd.h> @@ -184,8 +184,8 @@ static int pmus_cmp(void *priv __maybe_unused, static void pmu_read_sysfs(bool core_only) { int fd; - DIR *dir; - struct dirent *dent; + struct io_dir dir; + struct io_dirent64 *dent; if (read_sysfs_all_pmus || (core_only && read_sysfs_core_pmus)) return; @@ -194,13 +194,9 @@ static void pmu_read_sysfs(bool core_only) if (fd < 0) return; - dir = fdopendir(fd); - if (!dir) { - close(fd); - return; - } + io_dir__init(&dir, fd); - while ((dent = readdir(dir))) { + while ((dent = io_dir__readdir(&dir)) != NULL) { if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, "..")) continue; if (core_only && !is_pmu_core(dent->d_name)) @@ -209,7 +205,7 @@ static void pmu_read_sysfs(bool core_only) perf_pmu__find2(fd, dent->d_name); } - closedir(dir); + close(fd); if (list_empty(&core_pmus)) { if (!perf_pmu__create_placeholder_core_pmu(&core_pmus)) pr_err("Failure to set up any core PMUs\n"); @@ -563,8 +559,8 @@ bool perf_pmus__supports_extended_type(void) char *perf_pmus__default_pmu_name(void) { int fd; - DIR *dir; - struct dirent *dent; + struct io_dir dir; + struct io_dirent64 *dent; char *result = NULL; if (!list_empty(&core_pmus)) @@ -574,13 +570,9 @@ char *perf_pmus__default_pmu_name(void) if (fd < 0) return strdup("cpu"); - dir = fdopendir(fd); - if (!dir) { - close(fd); - return strdup("cpu"); - } + io_dir__init(&dir, fd); - while ((dent = readdir(dir))) { + while ((dent = io_dir__readdir(&dir)) != NULL) { if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, "..")) continue; if (is_pmu_core(dent->d_name)) { @@ -589,7 +581,7 @@ char *perf_pmus__default_pmu_name(void) } } - closedir(dir); + close(fd); return result ?: strdup("cpu"); } -- 2.43.0.rc2.451.g8631bc7472-goog
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