Merge branch 'linus' into x86/urgent

Merge reason: Merge upstream commits to avoid conflicts in upcoming patches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 178 insertions, 0 deletions

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
new file mode 100644
index 000000000000..9fea75535221
--- /dev/null
+++ b/tools/perf/util/cgroup.c
@@ -0,0 +1,178 @@
+#include "util.h"
+#include "../perf.h"
+#include "parse-options.h"
+#include "evsel.h"
+#include "cgroup.h"
+#include "debugfs.h" /* MAX_PATH, STR() */
+#include "evlist.h"
+
+int nr_cgroups;
+
+static int
+cgroupfs_find_mountpoint(char *buf, size_t maxlen)
+{
+        FILE *fp;
+        char mountpoint[MAX_PATH+1], tokens[MAX_PATH+1], type[MAX_PATH+1];
+        char *token, *saved_ptr;
+        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(MAX_PATH)"s %"STR(MAX_PATH)"s %"
+                                STR(MAX_PATH)"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[MAX_PATH+1];
+        char mnt[MAX_PATH+1];
+        int fd;
+
+
+        if (cgroupfs_find_mountpoint(mnt, MAX_PATH+1))
+                return -1;
+
+        snprintf(path, MAX_PATH, "%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
+         */
+        list_for_each_entry(counter, &evlist->entries, node) {
+                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;
+        list_for_each_entry(counter, &evlist->entries, node) {
+                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);
+                free(cgrp->name);
+                free(cgrp);
+        }
+}
+
+int parse_cgroups(const struct option *opt __used, const char *str,
+                  int unset __used)
+{
+        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;
+}