diff options
author | Namhyung Kim | 2020-12-16 18:05:55 +0900 |
---|---|---|
committer | Arnaldo Carvalho de Melo | 2021-02-17 15:08:32 -0300 |
commit | 6fd99b7f625c1fa0bbedbad03dc36e16e37e1777 (patch) | |
tree | 8ec3824214a2a0d18f72c20ef8c8212fe75a43f4 /tools/lib | |
parent | 27ab1c1c06529056df498b9647c03167e682b4d9 (diff) |
tools api fs: Diet cgroupfs_find_mountpoint()
Reduce the number of buffers and hopefully make it more efficient. :)
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20201216090556.813996-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/lib')
-rw-r--r-- | tools/lib/api/fs/cgroup.c | 70 |
1 files changed, 45 insertions, 25 deletions
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c index 813236d8ca48..262a4229e293 100644 --- a/tools/lib/api/fs/cgroup.c +++ b/tools/lib/api/fs/cgroup.c @@ -11,9 +11,10 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys) { FILE *fp; - char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; - char path_v2[PATH_MAX + 1]; - char *token, *saved_ptr = NULL; + char *line = NULL; + size_t len = 0; + char *p, *path; + char mountpoint[PATH_MAX]; fp = fopen("/proc/mounts", "r"); if (!fp) @@ -25,38 +26,57 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys) * the given subsystem. If we found v1, just use it. If not we can * use v2 path as a fallback. */ - path_v2[0] = '\0'; + mountpoint[0] = '\0'; - while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %" - __stringify(PATH_MAX)"s %*d %*d\n", - mountpoint, type, tokens) == 3) { + /* + * The /proc/mounts has the follow format: + * + * <devname> <mount point> <fs type> <options> ... + * + */ + while (getline(&line, &len, fp) != -1) { + /* skip devname */ + p = strchr(line, ' '); + if (p == NULL) + continue; - if (!strcmp(type, "cgroup")) { + /* save the mount point */ + path = ++p; + p = strchr(p, ' '); + if (p == NULL) + continue; - token = strtok_r(tokens, ",", &saved_ptr); + *p++ = '\0'; - while (token != NULL) { - if (subsys && !strcmp(token, subsys)) { - /* found */ - fclose(fp); + /* check filesystem type */ + if (strncmp(p, "cgroup", 6)) + continue; - if (strlen(mountpoint) < maxlen) { - strcpy(buf, mountpoint); - return 0; - } - return -1; - } - token = strtok_r(NULL, ",", &saved_ptr); - } + if (p[6] == '2') { + /* save cgroup v2 path */ + strcpy(mountpoint, path); + continue; } - if (!strcmp(type, "cgroup2")) - strcpy(path_v2, mountpoint); + /* now we have cgroup v1, check the options for subsystem */ + p += 7; + + p = strstr(p, subsys); + if (p == NULL) + continue; + + /* sanity check: it should be separated by a space or a comma */ + if (!strchr(" ,", p[-1]) || !strchr(" ,", p[strlen(subsys)])) + continue; + + strcpy(mountpoint, path); + break; } + free(line); fclose(fp); - if (path_v2[0] && strlen(path_v2) < maxlen) { - strcpy(buf, path_v2); + if (mountpoint[0] && strlen(mountpoint) < maxlen) { + strcpy(buf, mountpoint); return 0; } return -1; |