• Yonghong Song's avatar
    bpf: implement bpf_get_current_cgroup_id() helper · bf6fa2c8
    Yonghong Song authored
    bpf has been used extensively for tracing. For example, bcc
    contains an almost full set of bpf-based tools to trace kernel
    and user functions/events. Most tracing tools are currently
    either filtered based on pid or system-wide.
    
    Containers have been used quite extensively in industry and
    cgroup is often used together to provide resource isolation
    and protection. Several processes may run inside the same
    container. It is often desirable to get container-level tracing
    results as well, e.g. syscall count, function count, I/O
    activity, etc.
    
    This patch implements a new helper, bpf_get_current_cgroup_id(),
    which will return cgroup id based on the cgroup within which
    the current task is running.
    
    The later patch will provide an example to show that
    userspace can get the same cgroup id so it could
    configure a filter or policy in the bpf program based on
    task cgroup id.
    
    The helper is currently implemented for tracing. It can
    be added to other program types as well when needed.
    Acked-by: 's avatarAlexei Starovoitov <ast@kernel.org>
    Signed-off-by: 's avatarYonghong Song <yhs@fb.com>
    Signed-off-by: 's avatarAlexei Starovoitov <ast@kernel.org>
    bf6fa2c8
helpers.c 4.84 KB