diff options
| author | Namhyung Kim <namhyung@kernel.org> | 2020-12-16 18:05:56 +0900 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-02-17 15:09:08 -0300 |
| commit | 48859e5293a261437deb0231d78a388e242ed2d3 (patch) | |
| tree | d9053042a5878714b76fd3c5ec68f9e8dcfc107a /tools | |
| parent | 6fd99b7f625c1fa0bbedbad03dc36e16e37e1777 (diff) | |
tools api fs: Cache cgroupfs mount point
Currently it parses the /proc file everytime it opens a file in the
cgroupfs. Save the last result to avoid it (assuming it won't be
changed between the accesses).
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.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/20201216090556.813996-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/api/fs/cgroup.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c index 262a4229e293..1573dae4259d 100644 --- a/tools/lib/api/fs/cgroup.c +++ b/tools/lib/api/fs/cgroup.c @@ -8,6 +8,14 @@ #include <string.h> #include "fs.h" +struct cgroupfs_cache_entry { + char subsys[32]; + char mountpoint[PATH_MAX]; +}; + +/* just cache last used one */ +static struct cgroupfs_cache_entry cached; + int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys) { FILE *fp; @@ -16,6 +24,14 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys) char *p, *path; char mountpoint[PATH_MAX]; + if (!strcmp(cached.subsys, subsys)) { + if (strlen(cached.mountpoint) < maxlen) { + strcpy(buf, cached.mountpoint); + return 0; + } + return -1; + } + fp = fopen("/proc/mounts", "r"); if (!fp) return -1; @@ -75,6 +91,9 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys) free(line); fclose(fp); + strncpy(cached.subsys, subsys, sizeof(cached.subsys) - 1); + strcpy(cached.mountpoint, mountpoint); + if (mountpoint[0] && strlen(mountpoint) < maxlen) { strcpy(buf, mountpoint); return 0; |