log_errno
log_errno("moving self to original cgroup %s\n", env.orig_cgroup);
log_errno("deletion of cgroup %s", env.stat_cgroup);
log_errno("reading /proc/self/mounts");
log_errno("reading /proc/self/cgroup");
log_errno("creation of cgroup %s", buf);
log_errno("entering cgroup %s", buf);
log_errno("opening %s", buf);
log_errno("pread(%s/memory.peak)", env.stat_cgroup);
log_errno("%s/memory.peak:strtoll(%s)", env.stat_cgroup, buf);
log_errno("pwrite(%s/memory.peak)", env.stat_cgroup);