From: Namhyung Kim <namhyung@kernel.org> The read_cgroup_id() is to read a cgroup id from a file handle using name_to_handle_at(2) for the given cgroup. It'll be used by bperf cgroup stat later. Committer notes: -int read_cgroup_id(struct cgroup *cgrp) +static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused) To fix the build when HAVE_FILE_HANDLE is not defined. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210625071826.608504-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/cgroup.c | 25 +++++++++++++++++++++++++ tools/perf/util/cgroup.h | 10 ++++++++++ 2 files changed, 35 insertions(+) diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index b81324a13a2b..677144aa2af2 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -35,6 +35,31 @@ static int open_cgroup(const char *name) return fd; } +#ifdef HAVE_FILE_HANDLE +int read_cgroup_id(struct cgroup *cgrp) +{ + char path[PATH_MAX + 1]; + char mnt[PATH_MAX + 1]; + struct { + struct file_handle fh; + uint64_t cgroup_id; + } handle; + int mount_id; + + if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event")) + return -1; + + scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name); + + handle.fh.handle_bytes = sizeof(handle.cgroup_id); + if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) + return -1; + + cgrp->id = handle.cgroup_id; + return 0; +} +#endif /* HAVE_FILE_HANDLE */ + static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str) { struct evsel *counter; diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h index 162906f3412a..f3c978746999 100644 --- a/tools/perf/util/cgroup.h +++ b/tools/perf/util/cgroup.h @@ -2,6 +2,7 @@ #ifndef __CGROUP_H__ #define __CGROUP_H__ +#include <linux/compiler.h> #include <linux/refcount.h> #include <linux/rbtree.h> #include "util/env.h" @@ -38,4 +39,13 @@ struct cgroup *cgroup__find(struct perf_env *env, uint64_t id); void perf_env__purge_cgroups(struct perf_env *env); +#ifdef HAVE_FILE_HANDLE +int read_cgroup_id(struct cgroup *cgrp); +#else +static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused) +{ + return -1; +} +#endif /* HAVE_FILE_HANDLE */ + #endif /* __CGROUP_H__ */ -- 2.34.1