Merge "GPU Memory: add errno to error log messages"

    // Make sure bpf programs are loaded

    bpf::waitForProgsLoaded();

    int fd = bpf::bpfFdGet(kGpuMemTotalProgPath, BPF_F_RDONLY);

    errno = 0;

    int fd = bpf::retrieveProgram(kGpuMemTotalProgPath);

    if (fd < 0) {

        ALOGE("Failed to retrieve pinned program from %s", kGpuMemTotalProgPath);

        ALOGE("Failed to retrieve pinned program from %s [%d(%s)]", kGpuMemTotalProgPath, errno,

              strerror(errno));

        return;

    }

    // Attach the program to the tracepoint, and the tracepoint is automatically enabled here.

    errno = 0;

    int count = 0;

    while (bpf_attach_tracepoint(fd, kGpuMemTraceGroup, kGpuMemTotalTracepoint) < 0) {

        if (++count > kGpuWaitTimeout) {

            ALOGE("Failed to attach bpf program to %s/%s tracepoint", kGpuMemTraceGroup,

                  kGpuMemTotalTracepoint);

            ALOGE("Failed to attach bpf program to %s/%s tracepoint [%d(%s)]", kGpuMemTraceGroup,

                  kGpuMemTotalTracepoint, errno, strerror(errno));

            return;

        }

        // Retry until GPU driver loaded or timeout.

    }

    // Use the read-only wrapper BpfMapRO to properly retrieve the read-only map.

    errno = 0;

    auto map = bpf::BpfMapRO<uint64_t, uint64_t>(kGpuMemTotalMapPath);

    if (!map.isValid()) {

        ALOGE("Failed to create bpf map from %s", kGpuMemTotalMapPath);

        ALOGE("Failed to create bpf map from %s [%d(%s)]", kGpuMemTotalMapPath, errno,

              strerror(errno));

        return;

    }

    setGpuMemTotalMap(map);