Kernel now supports cgroup bps and iops hard limit by io-throttling.
But that's not a scalable way, because block devices' bandwith is
always changing over time.
This patch dynamically adjusts bps limit of each blkio cgroup according
to its pre-set weight. Additionally, if a process has not issued any io
request during a time window, its weight will be shared by other processes
until its next io request.
Signed-off-by: Lei Chen <lennychen@tencent.com>
Lei Chen