diff options
| -rw-r--r-- | Documentation/cgroup-v2.txt | 12 | ||||
| -rw-r--r-- | kernel/events/core.c | 6 | ||||
| -rw-r--r-- | tools/perf/util/cgroup.c | 26 |
3 files changed, 37 insertions, 7 deletions
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index f6f54107fb4d..227ce4883720 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -49,6 +49,8 @@ CONTENTS 5-3-2. Writeback 5-4. PID 5-4-1. PID Interface Files + 5-5. Misc + 5-5-1. perf_event 6. Namespace 6-1. Basics 6-2. The Root and Views @@ -1160,6 +1162,16 @@ through fork() or clone(). These will return -EAGAIN if the creation of a new process would cause a cgroup policy to be violated. +5-5. Misc + +5-5-1. perf_event + +perf_event controller, if not mounted on a legacy hierarchy, is +automatically enabled on the v2 hierarchy so that perf events can +always be filtered by cgroup v2 path. The controller can still be +moved to a legacy hierarchy after v2 hierarchy is populated. + + 6. Namespace 6-1. Basics diff --git a/kernel/events/core.c b/kernel/events/core.c index ab15509fab8c..d72128dce1e0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10792,5 +10792,11 @@ struct cgroup_subsys perf_event_cgrp_subsys = { .css_alloc = perf_cgroup_css_alloc, .css_free = perf_cgroup_css_free, .attach = perf_cgroup_attach, + /* + * Implicitly enable on dfl hierarchy so that perf events can + * always be filtered by cgroup2 path as long as perf_event + * controller is not mounted on a legacy hierarchy. + */ + .implicit_on_dfl = true, }; #endif /* CONFIG_CGROUP_PERF */ diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index 8fdee24725a7..eafbf11442b2 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -12,8 +12,8 @@ cgroupfs_find_mountpoint(char *buf, size_t maxlen) { FILE *fp; char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; + char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path; char *token, *saved_ptr = NULL; - int found = 0; fp = fopen("/proc/mounts", "r"); if (!fp) @@ -24,31 +24,43 @@ cgroupfs_find_mountpoint(char *buf, size_t maxlen) * and inspect every cgroupfs mount point to find one that has * perf_event subsystem */ + path_v1[0] = '\0'; + path_v2[0] = '\0'; + 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")) { + if (!path_v1[0] && !strcmp(type, "cgroup")) { token = strtok_r(tokens, ",", &saved_ptr); while (token != NULL) { if (!strcmp(token, "perf_event")) { - found = 1; + strcpy(path_v1, mountpoint); break; } token = strtok_r(NULL, ",", &saved_ptr); } } - if (found) + + if (!path_v2[0] && !strcmp(type, "cgroup2")) + strcpy(path_v2, mountpoint); + + if (path_v1[0] && path_v2[0]) break; } fclose(fp); - if (!found) + + if (path_v1[0]) + path = path_v1; + else if (path_v2[0]) + path = path_v2; + else return -1; - if (strlen(mountpoint) < maxlen) { - strcpy(buf, mountpoint); + if (strlen(path) < maxlen) { + strcpy(buf, path); return 0; } return -1; |