[libvirt] [PATCH 0/5] Make sure internal blkiotune values are in sync

We were blindly setting blkiotune values for devices, but kernel can throw some of them away. This series reworks the logic the same wayother tuning values are updated. That is, after the value gets set, it is read back again to make sure internal structures are in sync and we can return the values from them. Little example should clear up everything. Before: ======= $ virsh blkiotune dummy --device-read-bytes-sec /dev/sda,18446744073709551614 $ virsh blkiotune dummy weight : 500 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: /dev/sda,18446744073709551614 device_write_bytes_sec: $ cat /sys/fs/cgroup/blkio/machine/dummy.libvirt-qemu/blkio.throttle.read_bps_device 8:0 18446744073709551614 $ virsh blkiotune dummy --device-read-bytes-sec /dev/sda,18446744073709551615 $ virsh blkiotune dummy weight : 500 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: /dev/sda,18446744073709551615 device_write_bytes_sec: $ cat /sys/fs/cgroup/blkio/machine/dummy.libvirt-qemu/blkio.throttle.read_bps_device $ After: ====== $ virsh blkiotune dummy --device-read-bytes-sec /dev/sda,18446744073709551614 $ virsh blkiotune dummy weight : 500 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: /dev/sda,18446744073709551614 device_write_bytes_sec: $ cat /sys/fs/cgroup/blkio/machine/dummy.libvirt-qemu/blkio.throttle.read_bps_device 8:0 18446744073709551614 $ virsh blkiotune dummy --device-read-bytes-sec /dev/sda,18446744073709551615 $ virsh blkiotune dummy weight : 500 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: device_write_bytes_sec: $ cat /sys/fs/cgroup/blkio/machine/dummy.libvirt-qemu/blkio.throttle.read_bps_device $ Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1165580 Martin Kletzander (5): util: Add virStringGetFirstWithPrefix util: Add virCgroupGetBlockDevString util: Add getters for cgroup block device I/O throttling lxc: Sync BlkioDevice values when setting them in cgroups qemu: Sync BlkioDevice values when setting them in cgroups src/libvirt_private.syms | 6 + src/lxc/lxc_cgroup.c | 20 ++- src/lxc/lxc_driver.c | 25 ++- src/qemu/qemu_cgroup.c | 20 ++- src/qemu/qemu_driver.c | 25 ++- src/util/vircgroup.c | 457 +++++++++++++++++++++++++++++++++++------------ src/util/vircgroup.h | 20 +++ src/util/virstring.c | 17 ++ src/util/virstring.h | 2 + 9 files changed, 459 insertions(+), 133 deletions(-) -- 2.5.0