Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / tools / perf / util / cgroup.c

diff --git a/kernel/tools/perf/util/cgroup.c b/kernel/tools/perf/util/cgroup.c
new file mode 100644 (file)
index 0000000..88f7be3
--- /dev/null
+++ b/kernel/tools/perf/util/cgroup.c
@@ -0,0 +1,177 @@
+#include "util.h"
+#include "../perf.h"
+#include "parse-options.h"
+#include "evsel.h"
+#include "cgroup.h"
+#include "evlist.h"
+
+int nr_cgroups;
+
+static int
+cgroupfs_find_mountpoint(char *buf, size_t maxlen)
+{
+       FILE *fp;
+       char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
+       char *token, *saved_ptr = NULL;
+       int found = 0;
+
+       fp = fopen("/proc/mounts", "r");
+       if (!fp)
+               return -1;
+
+       /*
+        * in order to handle split hierarchy, we need to scan /proc/mounts
+        * and inspect every cgroupfs mount point to find one that has
+        * perf_event subsystem
+        */
+       while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %"
+                               STR(PATH_MAX)"s %*d %*d\n",
+                               mountpoint, type, tokens) == 3) {
+
+               if (!strcmp(type, "cgroup")) {
+
+                       token = strtok_r(tokens, ",", &saved_ptr);
+
+                       while (token != NULL) {
+                               if (!strcmp(token, "perf_event")) {
+                                       found = 1;
+                                       break;
+                               }
+                               token = strtok_r(NULL, ",", &saved_ptr);
+                       }
+               }
+               if (found)
+                       break;
+       }
+       fclose(fp);
+       if (!found)
+               return -1;
+
+       if (strlen(mountpoint) < maxlen) {
+               strcpy(buf, mountpoint);
+               return 0;
+       }
+       return -1;
+}
+
+static int open_cgroup(char *name)
+{
+       char path[PATH_MAX + 1];
+       char mnt[PATH_MAX + 1];
+       int fd;
+
+
+       if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
+               return -1;
+
+       snprintf(path, PATH_MAX, "%s/%s", mnt, name);
+
+       fd = open(path, O_RDONLY);
+       if (fd == -1)
+               fprintf(stderr, "no access to cgroup %s\n", path);
+
+       return fd;
+}
+
+static int add_cgroup(struct perf_evlist *evlist, char *str)
+{
+       struct perf_evsel *counter;
+       struct cgroup_sel *cgrp = NULL;
+       int n;
+       /*
+        * check if cgrp is already defined, if so we reuse it
+        */
+       evlist__for_each(evlist, counter) {
+               cgrp = counter->cgrp;
+               if (!cgrp)
+                       continue;
+               if (!strcmp(cgrp->name, str))
+                       break;
+
+               cgrp = NULL;
+       }
+
+       if (!cgrp) {
+               cgrp = zalloc(sizeof(*cgrp));
+               if (!cgrp)
+                       return -1;
+
+               cgrp->name = str;
+
+               cgrp->fd = open_cgroup(str);
+               if (cgrp->fd == -1) {
+                       free(cgrp);
+                       return -1;
+               }
+       }
+
+       /*
+        * find corresponding event
+        * if add cgroup N, then need to find event N
+        */
+       n = 0;
+       evlist__for_each(evlist, counter) {
+               if (n == nr_cgroups)
+                       goto found;
+               n++;
+       }
+       if (cgrp->refcnt == 0)
+               free(cgrp);
+
+       return -1;
+found:
+       cgrp->refcnt++;
+       counter->cgrp = cgrp;
+       return 0;
+}
+
+void close_cgroup(struct cgroup_sel *cgrp)
+{
+       if (!cgrp)
+               return;
+
+       /* XXX: not reentrant */
+       if (--cgrp->refcnt == 0) {
+               close(cgrp->fd);
+               zfree(&cgrp->name);
+               free(cgrp);
+       }
+}
+
+int parse_cgroups(const struct option *opt __maybe_unused, const char *str,
+                 int unset __maybe_unused)
+{
+       struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
+       const char *p, *e, *eos = str + strlen(str);
+       char *s;
+       int ret;
+
+       if (list_empty(&evlist->entries)) {
+               fprintf(stderr, "must define events before cgroups\n");
+               return -1;
+       }
+
+       for (;;) {
+               p = strchr(str, ',');
+               e = p ? p : eos;
+
+               /* allow empty cgroups, i.e., skip */
+               if (e - str) {
+                       /* termination added */
+                       s = strndup(str, e - str);
+                       if (!s)
+                               return -1;
+                       ret = add_cgroup(evlist, s);
+                       if (ret) {
+                               free(s);
+                               return -1;
+                       }
+               }
+               /* nr_cgroups is increased een for empty cgroups */
+               nr_cgroups++;
+               if (!p)
+                       break;
+               str = p+1;
+       }
+       return 0;
+}