Commits
Shaohua Li committed eff2c4f1087
nullb: bandwidth control In test, we usually expect controllable disk speed. For example, in a raid array, we'd like some disks are fast and some are slow. MD RAID actually has a feature for this. To test the feature, we'd like to make the disk run in specific speed. block throttling probably can be used for this purpose, but it requires cgroup setup. Here we just implement a simple throttling mechanism in the driver. There is slight fluctuation in the mechanism, but it's good enough for test. To configure the bandwidth cap, user sets the 'mbps' attribute. mbps is MB/s. Based on original patch from Kyungchan Koh Signed-off-by: Kyungchan Koh <kkc6196@fb.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>