Merge "libtimeinstate: tolerate multiple calls to startTrackingUidTimes"

static std::mutex gInitializedMutex;

static bool gInitialized = false;

static std::mutex gTrackingMutex;

static bool gTracking = false;

static uint32_t gNPolicies = 0;

static uint32_t gNCpus = 0;

static std::vector<std::vector<uint32_t>> gPolicyFreqs;

// This function should *not* be called while tracking is already active; doing so is unnecessary

// and can lead to accounting errors.

bool startTrackingUidTimes() {

    std::lock_guard<std::mutex> guard(gTrackingMutex);

    if (!initGlobals()) return false;

    if (gTracking) return true;

    unique_fd cpuPolicyFd(bpf_obj_get_wronly(BPF_FS_PATH "map_time_in_state_cpu_policy_map"));

    if (cpuPolicyFd < 0) return false;

        if (writeToMapEntry(policyFreqIdxFd, &i, &zero, BPF_ANY)) return false;

    }

    return attachTracepointProgram("sched", "sched_switch") &&

    gTracking = attachTracepointProgram("sched", "sched_switch") &&

            attachTracepointProgram("power", "cpu_frequency");

    return gTracking;

}

std::optional<std::vector<std::vector<uint32_t>>> getCpuFreqs() {