vcl: nest vcl_mq_epfd to support epoll_wait without high CPU usage
Now, libc epfd and vls epfd are independent and can only epoll_wait independently without timeout, then app calling epoll_wait will occupy high CPU. So we nest vcl_mq_epfd into libc epfd when using eventfd with VPP, and then we can only epoll_wait libc epfd with specified timeout.
Type: feature
Signed-off-by: hanlin <hanlin_wang@163.com>
Change-Id: I6b6e0f501c769e186714bfbc187cfaed2533b4c2
Signed-off-by: hanlin <hanlin_wang@163.com>