Hi Alasdair and all, This is the dm-ioband version 1.11.0 release. This patch can be applied cleanly to current agk's tree. Alasdair, please give some comments and suggestions. Changes from the previous release: - Classify IOs in sync/async instead of read/write since the IO request allocation/congestion logic were changed to be sync/async based. - IOs belong to the real-time class are dispatched in preference to other IOs, regardless of the assigned bandwidth. Thanks, Ryo Tsuruta Dm-ioband is an I/O bandwidth controller implemented as a device-mapper driver, which gives specified bandwidth to each job running on the same physical device. A lot more information (manual, benchmark results, all-in-one patch and so on) is available at http://people.valinux.co.jp/~ryov/dm-ioband/ . I welcome any feed-backs and suggestions. Signed-off-by: Ryo Tsuruta <ryov@xxxxxxxxxxxxx> Signed-off-by: Hirokazu Takahashi <taka@xxxxxxxxxxxxx> --- Documentation/device-mapper/ioband.txt | 981 +++++++++++++++++++++++ drivers/md/Kconfig | 13 drivers/md/Makefile | 2 drivers/md/dm-ioband-ctl.c | 1358 +++++++++++++++++++++++++++++++++ drivers/md/dm-ioband-policy.c | 454 +++++++++++ drivers/md/dm-ioband-type.c | 76 + drivers/md/dm-ioband.h | 186 ++++ 7 files changed, 3070 insertions(+) Index: linux-2.6.30-rc4/Documentation/device-mapper/ioband.txt =================================================================== --- /dev/null +++ linux-2.6.30-rc4/Documentation/device-mapper/ioband.txt @@ -0,0 +1,981 @@ + Block I/O bandwidth control: dm-ioband + + ------------------------------------------------------- + + Table of Contents + + [1]What's dm-ioband all about? + + [2]Differences from the CFQ I/O scheduler + + [3]How dm-ioband works. + + [4]Setup and Installation + + [5]Getting started + + [6]Command Reference + + [7]Examples + +What's dm-ioband all about? + + dm-ioband is an I/O bandwidth controller implemented as a device-mapper + driver. Several jobs using the same block device have to share the + bandwidth of the device. dm-ioband gives bandwidth to each job according + to its weight, which each job can set its own value to. + + A job is a group of processes with the same pid or pgrp or uid or a + virtual machine such as KVM or Xen. A job can also be a cgroup by applying + the bio-cgroup patch, which can be found at + [8]http://people.valinux.co.jp/~ryov/bio-cgroup/. + + +------+ +------+ +------+ +------+ +------+ +------+ + |cgroup| |cgroup| | the | | pid | | pid | | the | jobs + | A | | B | |others| | X | | Y | |others| + +--|---+ +--|---+ +--|---+ +--|---+ +--|---+ +--|---+ + +--V----+---V---+----V---+ +--V----+---V---+----V---+ + | group | group | default| | group | group | default| ioband groups + | | | group | | | | group | + +-------+-------+--------+ +-------+-------+--------+ + | ioband1 | | ioband2 | ioband devices + +-----------|------------+ +-----------|------------+ + +-----------V--------------+-------------V------------+ + | | | + | sdb1 | sdb2 | block devices + +--------------------------+--------------------------+ + + + -------------------------------------------------------------------------- + +Differences from the CFQ I/O scheduler + + Dm-ioband is flexible to configure the bandwidth settings. + + Dm-ioband can work with any type of I/O scheduler such as the NOOP + scheduler, which is often chosen for high-end storages, since it is + implemented outside the I/O scheduling layer. It allows both of partition + based bandwidth control and job --- a group of processes --- based + control. In addition, it can set different configuration on each block + device to control its bandwidth. + + Meanwhile the current implementation of the CFQ scheduler has 8 IO + priority levels and all jobs whose processes have the same IO priority + share the bandwidth assigned to this level between them. And IO priority + is an attribute of a process, so that it equally effects to all block + devices. + + -------------------------------------------------------------------------- + +How dm-ioband works. + + Every ioband device has one ioband group, which by default is called the + default group. + + Ioband devices can also have extra ioband groups in them. Each ioband + group has a job to support and a weight. Proportional to the weight, + dm-ioband gives tokens to the group. + + A group passes on I/O requests that its job issues to the underlying + layer so long as it has tokens left, while requests are blocked if there + aren't any tokens left in the group. Tokens are refilled once all of + groups that have requests on a given underlying block device use up their + tokens. + + There are two policies for token consumption. One is that a token is + consumed for each I/O request. The other is that a token is consumed for + each I/O sector, for example, one I/O request which consists of + 4Kbytes(512bytes * 8 sectors) read consumes 8 tokens. A user can choose + either policy. + + With this approach, a job running on an ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + +Setup and Installation + + Build a kernel with these options enabled: + + CONFIG_MD + CONFIG_BLK_DEV_DM + CONFIG_DM_IOBAND + + + If compiled as module, use modprobe to load dm-ioband. + + # make modules + # make modules_install + # depmod -a + # modprobe dm-ioband + + + "dmsetup targets" command shows all available device-mapper targets. + "ioband" and the version number are displayed when dm-ioband has been + loaded. + + # dmsetup targets | grep ioband + ioband v1.0.0 + + + -------------------------------------------------------------------------- + +Getting started + + The following is a brief description how to control the I/O bandwidth of + disks. In this description, we'll take one disk with two partitions as an + example target. + + -------------------------------------------------------------------------- + + Create and map ioband devices + + Create two ioband devices "ioband1" and "ioband2". "ioband1" is mapped + to "/dev/sda1" and has a weight of 40. "ioband2" is mapped to "/dev/sda2" + and has a weight of 10. "ioband1" can use 80% --- 40/(40+10)*100 --- of + the bandwidth of "/dev/sda" while "ioband2" can use 20%. + + # echo "0 $(blockdev --getsize /dev/sda1) ioband /dev/sda1 1 0 0 none" \ + "weight 0 :40" | dmsetup create ioband1 + # echo "0 $(blockdev --getsize /dev/sda2) ioband /dev/sda2 1 0 0 none" \ + "weight 0 :10" | dmsetup create ioband2 + + + If the commands are successful then the device files + "/dev/mapper/ioband1" and "/dev/mapper/ioband2" will have been created. + + -------------------------------------------------------------------------- + + Additional bandwidth control + + In this example two extra ioband groups are created on "ioband1." + + First, set the ioband group type as user. Next, create two ioband groups + that have id 1000 and 2000. Then, give weights of 30 and 20 to the ioband + groups respectively. + + # dmsetup message ioband1 0 type user + # dmsetup message ioband1 0 attach 1000 + # dmsetup message ioband1 0 attach 2000 + # dmsetup message ioband1 0 weight 1000:30 + # dmsetup message ioband1 0 weight 2000:20 + + + Now the processes owned by uid 1000 can use 30% --- 30/(30+20+40+10)*100 + --- of the bandwidth of "/dev/sda" when the processes issue I/O requests + through "ioband1." The processes owned by uid 2000 can use 20% of the + bandwidth likewise. + + Table 1. Weight assignments + + +----------------------------------------------------------------+ + | ioband device | ioband group | ioband weight | + |---------------+--------------------------------+---------------| + | ioband1 | user id 1000 | 30 | + |---------------+--------------------------------+---------------| + | ioband1 | user id 2000 | 20 | + |---------------+--------------------------------+---------------| + | ioband1 | default group(the other users) | 40 | + |---------------+--------------------------------+---------------| + | ioband2 | default group | 10 | + +----------------------------------------------------------------+ + + -------------------------------------------------------------------------- + + Remove the ioband devices + + Remove the ioband devices when no longer used. + + # dmsetup remove ioband1 + # dmsetup remove ioband2 + + + -------------------------------------------------------------------------- + +Command Reference + + Create an ioband device + + SYNOPSIS + + dmsetup create IOBAND_DEVICE + + DESCRIPTION + + Create an ioband device with the given name IOBAND_DEVICE. + Generally, dmsetup reads a table from standard input. Each line of + the table specifies a single target and is of the form: + + start_sector num_sectors "ioband" device_file ioband_device_id \ + io_throttle io_limit ioband_group_type policy token_base \ + :weight [ioband_group_id:weight...] + + + start_sector, num_sectors + + The sector range of the underlying device where + dm-ioband maps. + + ioband + + Specify the string "ioband" as a target type. + + device_file + + Underlying device name. + + ioband_device_id + + The ID number for an ioband device. The same ID + must be set among the ioband devices that share the + same bandwidth. This is useful for grouping disk + drives partitioned from one disk drive such as RAID + drive or LVM logical striped volume. + + io_throttle + + When a device has a lot of tokens and the number of + in-flight I/Os in dm-ioband exceeds io_throttle, + dm-ioband gives priority to the device and issues + I/Os to the device until no tokens of the device are + left. If 0 is specified, the default value is used. + This setting applies all ioband devices which has the + same ioband device ID as you specified by + "ioband_device_id." + + io_limit + + Dm-ioband blocks all I/O requests for IOBAND_DEVICE + when the number of BIOs in progress exceeds this + value. If 0 is specified, the default value is used. + This setting applies all ioband devices which has the + same ioband device ID as you specified by + "ioband_device_id." + + ioband_group_type + + Specify how to evaluate the ioband group ID. The + type must be one of "none", "user", "gid", "pid" or + "pgrp." The type "cgroup" is enabled by applying the + bio-cgroup patch. Specify "none" if you don't need + any ioband groups other than the default ioband + group. + + policy + + Specify a bandwidth control policy. A user can + choose either policy "weight" or "weight-iosize." + This setting applies all ioband devices which has the + same ioband device ID as you specified by + "ioband_device_id." + + weight + + This policy controls bandwidth + according to the proportional to the + weight of each ioband group based on the + number of I/O requests. + + weight-iosize + + This policy controls bandwidth + according to the proportional to the + weight of each ioband group based on the + number of I/O sectors. + + token_base + + The number of tokens which specified by token_base + will be distributed to all ioband groups according to + the proportional to the weight of each ioband group. + If 0 is specified, the default value is used. This + setting applies all ioband devices which has the same + ioband device ID as you specified by + "ioband_device_id." + + ioband_group_id:weight + + Set the weight of the ioband group specified by + ioband_group_id. If ioband_group_id is omitted, the + weight is assigned to the default ioband group. + + EXAMPLE + + Create an ioband device with the following parameters: + + * Starting sector = "0" + + * The number of sectors = "$(blockdev --getsize /dev/sda1)" + + * Target type = "ioband" + + * Underlying device name = "/dev/sda1" + + * Ioband device ID = "128" + + * I/O throttle = "10" + + * I/O limit = "400" + + * Ioband group type = "user" + + * Bandwidth control policy = "weight" + + * Token base = "2048" + + * Weight for the default ioband group = "100" + + * Weight for the ioband group 1000 = "80" + + * Weight for the ioband group 2000 = "20" + + * Ioband device name = "ioband1" + + # echo "0 $(blockdev --getsize /dev/sda1) ioband" \ + "/dev/sda1 128 10 400 user weight 2048 :100 1000:80 2000:20" \ + | dmsetup create ioband1 + + + Create two device groups (ID=1,2). The bandwidths of these + device groups will be individually controlled. + + # echo "0 $(blockdev --getsize /dev/sda1) ioband /dev/sda1 1" \ + "0 0 none weight 0 :80" | dmsetup create ioband1 + # echo "0 $(blockdev --getsize /dev/sda2) ioband /dev/sda2 1" \ + "0 0 none weight 0 :20" | dmsetup create ioband2 + # echo "0 $(blockdev --getsize /dev/sdb3) ioband /dev/sdb3 2" \ + "0 0 none weight 0 :60" | dmsetup create ioband3 + # echo "0 $(blockdev --getsize /dev/sdb4) ioband /dev/sdb4 2" \ + "0 0 none weight 0 :40" | dmsetup create ioband4 + + + -------------------------------------------------------------------------- + + Remove the ioband device + + SYNOPSIS + + dmsetup remove IOBAND_DEVICE + + DESCRIPTION + + Remove the specified ioband device IOBAND_DEVICE. All the band + groups attached to the ioband device are also removed + automatically. + + EXAMPLE + + Remove ioband device "ioband1." + + # dmsetup remove ioband1 + + + -------------------------------------------------------------------------- + + Set an ioband group type + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 type TYPE + + DESCRIPTION + + Set an ioband group type of IOBAND_DEVICE. TYPE must be one of + "none", "user", "gid", "pid" or "pgrp." The type "cgroup" is + enabled by applying the bio-cgroup patch. Once the type is set, + new ioband groups can be created on IOBAND_DEVICE. + + EXAMPLE + + Set the ioband group type of ioband device "ioband1" to "user." + + # dmsetup message ioband1 0 type user + + + -------------------------------------------------------------------------- + + Create an ioband group + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 attach ID + + DESCRIPTION + + Create an ioband group and attach it to IOBAND_DEVICE. ID + specifies user-id, group-id, process-id or process-group-id + depending the ioband group type of IOBAND_DEVICE. + + EXAMPLE + + Create an ioband group which consists of all processes with + user-id 1000 and attach it to ioband device "ioband1." + + # dmsetup message ioband1 0 type user + # dmsetup message ioband1 0 attach 1000 + + + -------------------------------------------------------------------------- + + Detach the ioband group + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 detach ID + + DESCRIPTION + + Detach the ioband group specified by ID from ioband device + IOBAND_DEVICE. + + EXAMPLE + + Detach the ioband group with ID "2000" from ioband device + "ioband2." + + # dmsetup message ioband2 0 detach 1000 + + + -------------------------------------------------------------------------- + + Set bandwidth control policy + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 policy policy + + DESCRIPTION + + Set a bandwidth control policy. A user can choose either policy + "weight" or "weight-iosize." This setting applies all ioband + devices which has the same ioband device ID as IOBAND_DEVICE. + + weight + + This policy controls bandwidth according to the + proportional to the weight of each ioband group based + on the number of I/O requests. + + weight-iosize + + This policy controls bandwidth according to the + proportional to the weight of each ioband group based + on the number of I/O sectors. + + EXAMPLE + + Set bandwidth control policy of ioband devices which have the + same ioband device ID as "ioband1" to "weight-iosize." + + # dmsetup message ioband1 0 policy weight-iosize + + + -------------------------------------------------------------------------- + + Set the weight of an ioband group + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 weight VAL + + dmsetup message IOBAND_DEVICE 0 weight ID:VAL + + DESCRIPTION + + Set the weight of the ioband group specified by ID. Set the + weight of the default ioband group of IOBAND_DEVICE if ID isn't + specified. + + The following example means that "ioband1" can use 80% --- + 40/(40+10)*100 --- of the bandwidth of the underlying block device + while "ioband2" can use 20%. + + # dmsetup message ioband1 0 weight 40 + # dmsetup message ioband2 0 weight 10 + + + The following lines have the same effect as the above: + + # dmsetup message ioband1 0 weight 4 + # dmsetup message ioband2 0 weight 1 + + + VAL must be an integer larger than 0. The default value, which + is assigned to newly created ioband groups, is 100. + + EXAMPLE + + Set the weight of the default ioband group of "ioband1" to 40. + + # dmsetup message ioband1 0 weight 40 + + + Set the weight of the ioband group of "ioband1" with ID "1000" + to 10. + + # dmsetup message ioband1 0 weight 1000:10 + + + -------------------------------------------------------------------------- + + Set the number of tokens + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 token VAL + + DESCRIPTION + + The number of tokens will be distributed to all ioband groups + according to the proportional to the weight of each ioband group. + If 0 is specified, the default value is used. This setting applies + all ioband devices which has the same ioband device ID as + IOBAND_DEVICE + + EXAMPLE + + Set the number of tokens to 256. + + # dmsetup message ioband1 0 token 256 + + + -------------------------------------------------------------------------- + + Set a limit of how many tokens are carried over + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 carryover VAL + + DESCRIPTION + + When dm-ioband tries to refill an ioband group with tokens after + another ioband group is already refilled several times, dm-ioband + determines the number of tokens to refill by multiplying the + number of tokens refilled once by the smaller of how many times + the other group is already refilled or this limit. If 0 is + specified, the default value is used. This setting applies all + ioband devices which has the same ioband device ID as + IOBAND_DEVICE. + + EXAMPLE + + Set a limit for "ioband1" to 2. + + # dmsetup message ioband1 0 carryover 2 + + + -------------------------------------------------------------------------- + + Set I/O throttling + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 io_throttle VAL + + DESCRIPTION + + When a device has a lot of tokens and the number of in-flight + I/Os in dm-ioband exceeds io_throttle, dm-ioband gives priority to + the device and issues I/Os to the device until no tokens of the + device are left. If 0 is specified, the default value is used. + This setting applies all ioband devices which has the same ioband + device ID as you specified by "ioband_device_id." + + EXAMPLE + + Set the I/O throttling value of "ioband1" to 16. + + # dmsetup message ioband1 0 io_throttle 16 + + + -------------------------------------------------------------------------- + + Set I/O limiting + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 io_limit VAL + + DESCRIPTION + + Dm-ioband blocks all I/O requests for IOBAND_DEVICE when the + number of BIOs in progress exceeds this value. If 0 is specified, + the default value is used. This setting applies all ioband devices + which has the same ioband device ID as IOBAND_DEVICE. + + EXAMPLE + + Set the I/O limiting value of "ioband1" to 128. + + # dmsetup message ioband1 0 io_limit 128 + + + -------------------------------------------------------------------------- + + Display settings + + SYNOPSIS + + dmsetup table --target ioband + + DESCRIPTION + + Display the current table for the ioband device in a format. See + "dmsetup create" command for information on the table format. + + EXAMPLE + + The following output shows the current table of "ioband1." + + # dmsetup table --target ioband + ioband: 0 32129937 ioband1 8:29 128 10 400 user weight \ + 2048 :100 1000:80 2000:20 + + + -------------------------------------------------------------------------- + + Display Statistics + + SYNOPSIS + + dmsetup status --target ioband + + DESCRIPTION + + Display the statistics of all the ioband devices whose target + type is "ioband." + + The output format is as below. the first five columns shows: + + * ioband device name + + * logical start sector of the device (must be 0) + + * device size in sectors + + * target type (must be "ioband") + + * device group ID + + The remaining columns show the statistics of each ioband group + on the band device. Each group uses seven columns for its + statistics. + + * ioband group ID (-1 means default) + + * total read requests + + * delayed read requests + + * total read sectors + + * total write requests + + * delayed write requests + + * total write sectors + + EXAMPLE + + The following output shows the statistics of two ioband devices. + Ioband2 only has the default ioband group and ioband1 has three + (default, 1001, 1002) ioband groups. + + # dmsetup status + ioband2: 0 44371467 ioband 128 -1 143 90 424 122 78 352 + ioband1: 0 44371467 ioband 128 -1 223 172 408 211 136 600 1001 \ + 166 107 472 139 95 352 1002 211 146 520 210 147 504 + + + -------------------------------------------------------------------------- + + Reset status counter + + SYNOPSIS + + dmsetup message IOBAND_DEVICE 0 reset + + DESCRIPTION + + Reset the statistics of ioband device IOBAND_DEVICE. + + EXAMPLE + + Reset the statistics of "ioband1." + + # dmsetup message ioband1 0 reset + + + -------------------------------------------------------------------------- + +Examples + + Example #1: Bandwidth control on Partitions + + This example describes how to control the bandwidth with disk + partitions. The following diagram illustrates the configuration of this + example. You may want to run a database on /dev/mapper/ioband1 and web + applications on /dev/mapper/ioband2. + + /mnt1 /mnt2 mount points + | | + +-------------V------------+ +-------------V------------+ + | /dev/mapper/ioband1 | | /dev/mapper/ioband2 | ioband devices + +--------------------------+ +--------------------------+ + | default group | | default group | ioband groups + | (80) | | (40) | (weight) + +-------------|------------+ +-------------|------------+ + | | + +-------------V-------------+--------------V------------+ + | /dev/sda1 | /dev/sda2 | partitions + +---------------------------+---------------------------+ + + + To setup the above configuration, follow these steps: + + 1. Create ioband devices with the same device group ID and assign + weights of 80 and 40 to the default ioband groups respectively. + + # echo "0 $(blockdev --getsize /dev/sda1) ioband /dev/sda1 1 0 0" \ + "none weight 0 :80" | dmsetup create ioband1 + # echo "0 $(blockdev --getsize /dev/sda2) ioband /dev/sda2 1 0 0" \ + "none weight 0 :40" | dmsetup create ioband2 + + + 2. Create filesystems on the ioband devices and mount them. + + # mkfs.ext3 /dev/mapper/ioband1 + # mount /dev/mapper/ioband1 /mnt1 + + # mkfs.ext3 /dev/mapper/ioband2 + # mount /dev/mapper/ioband2 /mnt2 + + + -------------------------------------------------------------------------- + + Example #2: Bandwidth control on Logical Volumes + + This example is similar to the example #1 but it uses LVM logical + volumes instead of disk partitions. This example shows how to configure + ioband devices on two striped logical volumes. + + /mnt1 /mnt2 mount points + | | + +-------------V------------+ +-------------V------------+ + | /dev/mapper/ioband1 | | /dev/mapper/ioband2 | ioband devices + +--------------------------+ +--------------------------+ + | default group | | default group | ioband groups + | (80) | | (40) | (weight) + +-------------|------------+ +-------------|------------+ + | | + +-------------V------------+ +-------------V------------+ + | /dev/mapper/lv0 | | /dev/mapper/lv1 | striped logical + | | | | volumes + +-------------------------------------------------------+ + | vg0 | volume group + +-------------|----------------------------|------------+ + | | + +-------------V------------+ +-------------V------------+ + | /dev/sdb | | /dev/sdc | physical disks + +--------------------------+ +--------------------------+ + + + To setup the above configuration, follow these steps: + + 1. Initialize the partitions for use by LVM. + + # pvcreate /dev/sdb + # pvcreate /dev/sdc + + + 2. Create a new volume group named "vg0" with /dev/sdb and /dev/sdc. + + # vgcreate vg0 /dev/sdb /dev/sdc + + + 3. Create two logical volumes in "vg0." The volumes have to be striped. + + # lvcreate -n lv0 -i 2 -I 64 vg0 -L 1024M + # lvcreate -n lv1 -i 2 -I 64 vg0 -L 1024M + + + The rest is the same as the example #1. + + 4. Create ioband devices corresponding to each logical volume and + assign weights of 80 and 40 to the default ioband groups respectively. + + # echo "0 $(blockdev --getsize /dev/mapper/vg0-lv0)" \ + "ioband /dev/mapper/vg0-lv0 1 0 0 none weight 0 :80" | \ + dmsetup create ioband1 + # echo "0 $(blockdev --getsize /dev/mapper/vg0-lv1)" \ + "ioband /dev/mapper/vg0-lv1 1 0 0 none weight 0 :40" | \ + dmsetup create ioband2 + + + 5. Create filesystems on the ioband devices and mount them. + + # mkfs.ext3 /dev/mapper/ioband1 + # mount /dev/mapper/ioband1 /mnt1 + + # mkfs.ext3 /dev/mapper/ioband2 + # mount /dev/mapper/ioband2 /mnt2 + + + -------------------------------------------------------------------------- + + Example #3: Bandwidth control on processes + + This example describes how to control the bandwidth with groups of + processes. You may also want to run an additional application on the same + machine described in the example #1. This example shows how to add a new + ioband group for this application. + + /mnt1 /mnt2 mount points + | | + +-------------V------------+ +-------------V------------+ + | /dev/mapper/ioband1 | | /dev/mapper/ioband2 | ioband devices + +-------------+------------+ +-------------+------------+ + | default | | user=1000 | default | ioband groups + | (80) | | (20) | (40) | (weight) + +-------------+------------+ +-------------+------------+ + | | + +-------------V-------------+--------------V------------+ + | /dev/sda1 | /dev/sda2 | partitions + +---------------------------+---------------------------+ + + + The following shows to set up a new ioband group on the machine that is + already configured as the example #1. The application will have a weight + of 20 and run with user-id 1000 on /dev/mapper/ioband2. + + 1. Set the type of ioband2 to "user." + + # dmsetup message ioband2 0 type user. + + + 2. Create a new ioband group on ioband2. + + # dmsetup message ioband2 0 attach 1000 + + + 3. Assign weight of 10 to this newly created ioband group. + + # dmsetup message ioband2 0 weight 1000:20 + + + -------------------------------------------------------------------------- + + Example #4: Bandwidth control for Xen virtual block devices + + This example describes how to control the bandwidth for Xen virtual + block devices. The following diagram illustrates the configuration of this + example. + + Virtual Machine 1 Virtual Machine 2 virtual machines + | | + +-------------V------------+ +-------------V------------+ + | /dev/xvda1 | | /dev/xvda1 | virtual block + +-------------|------------+ +-------------|------------+ devices + | | + +-------------V------------+ +-------------V------------+ + | /dev/mapper/ioband1 | | /dev/mapper/ioband2 | ioband devices + +--------------------------+ +--------------------------+ + | default group | | default group | ioband groups + | (80) | | (40) | (weight) + +-------------|------------+ +-------------|------------+ + | | + +-------------V-------------+--------------V------------+ + | /dev/sda1 | /dev/sda2 | partitions + +---------------------------+---------------------------+ + + + The followings shows how to map ioband device "ioband1" and "ioband2" to + virtual block device "/dev/xvda1 on Virtual Machine 1" and "/dev/xvda1 on + Virtual Machine 2" respectively on the machine configured as the example + #1. Add the following lines to the configuration files that are referenced + when creating "Virtual Machine 1" and "Virtual Machine 2." + + For "Virtual Machine 1" + disk = [ 'phy:/dev/mapper/ioband1,xvda,w' ] + + For "Virtual Machine 2" + disk = [ 'phy:/dev/mapper/ioband2,xvda,w' ] + + + -------------------------------------------------------------------------- + + Example #5: Bandwidth control for Xen blktap devices + + This example describes how to control the bandwidth for Xen virtual + block devices when Xen blktap devices are used. The following diagram + illustrates the configuration of this example. + + Virtual Machine 1 Virtual Machine 2 virtual machines + | | + +-------------V------------+ +-------------V------------+ + | /dev/xvda1 | | /dev/xvda1 | virtual block + +-------------|------------+ +-------------|------------+ devices + | | + +-------------V----------------------------V------------+ + | /dev/mapper/ioband1 | ioband device + +---------------------------+---------------------------+ + | default group | default group | ioband groups + | (80) | (40) | (weight) + +-------------|-------------+--------------|------------+ + | | + +-------------|----------------------------|------------+ + | +----------V----------+ +----------V---------+ | + | | vm1.img | | vm2.img | | disk image files + | +---------------------+ +--------------------+ | + | /vmdisk | mount point + +---------------------------|---------------------------+ + | + +---------------------------V---------------------------+ + | /dev/sda1 | partition + +-------------------------------------------------------+ + + + To setup the above configuration, follow these steps: + + 1. Create an ioband device. + + # echo "0 $(blockdev --getsize /dev/sda1) ioband /dev/sda1" \ + "1 0 0 none weight 0 :100" | dmsetup create ioband1 + + + 2. Add the following lines to the configuration files that are + referenced when creating "Virtual Machine 1" and "Virtual Machine 2." + Disk image files "/vmdisk/vm1.img" and "/vmdisk/vm2.img" will be used. + + For "Virtual Machine 1" + disk = [ 'tap:aio:/vmdisk/vm1.img,xvda,w', ] + + For "Virtual Machine 1" + disk = [ 'tap:aio:/vmdisk/vm2.img,xvda,w', ] + + + 3. Run the virtual machines. + + # xm create vm1 + # xm create vm2 + + + 4. Find out the process IDs of the daemons which control the blktap + devices. + + # lsof /vmdisk/disk[12].img + COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME + tapdisk 15011 root 11u REG 253,0 2147483648 48961 /vmdisk/vm1.img + tapdisk 15276 root 13u REG 253,0 2147483648 48962 /vmdisk/vm2.img + + + 5. Create new ioband groups of pid 15011 and pid 15276, which are + process IDs of the tapdisks, and assign weight of 80 and 40 to the + groups respectively. + + # dmsetup message ioband1 0 type pid + # dmsetup message ioband1 0 attach 15011 + # dmsetup message ioband1 0 weight 15011:80 + # dmsetup message ioband1 0 attach 15276 + # dmsetup message ioband1 0 weight 15276:40 Index: linux-2.6.30-rc4/drivers/md/Kconfig =================================================================== --- linux-2.6.30-rc4.orig/drivers/md/Kconfig +++ linux-2.6.30-rc4/drivers/md/Kconfig @@ -283,4 +283,17 @@ config DM_UEVENT ---help--- Generate udev events for DM events. +config DM_IOBAND + tristate "I/O bandwidth control (EXPERIMENTAL)" + depends on BLK_DEV_DM && EXPERIMENTAL + ---help--- + This device-mapper target allows to define how the + available bandwidth of a storage device should be + shared between processes, cgroups, the partitions or the LUNs. + + Information on how to use dm-ioband is available in: + <file:Documentation/device-mapper/ioband.txt>. + + If unsure, say N. + endif # MD Index: linux-2.6.30-rc4/drivers/md/Makefile =================================================================== --- linux-2.6.30-rc4.orig/drivers/md/Makefile +++ linux-2.6.30-rc4/drivers/md/Makefile @@ -8,6 +8,7 @@ dm-multipath-y += dm-path-selector.o dm- dm-snapshot-y += dm-snap.o dm-exception-store.o dm-snap-transient.o \ dm-snap-persistent.o dm-mirror-y += dm-raid1.o +dm-ioband-y += dm-ioband-ctl.o dm-ioband-policy.o dm-ioband-type.o dm-log-clustered-y \ += dm-log-cluster.o dm-log-cluster-transfer.o md-mod-y += md.o bitmap.o @@ -37,6 +38,7 @@ obj-$(CONFIG_BLK_DEV_MD) += md-mod.o obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o obj-$(CONFIG_DM_CRYPT) += dm-crypt.o obj-$(CONFIG_DM_DELAY) += dm-delay.o +obj-$(CONFIG_DM_IOBAND) += dm-ioband.o obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o obj-$(CONFIG_DM_MULTIPATH_QL) += dm-queue-length.o obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o Index: linux-2.6.30-rc4/drivers/md/dm-ioband-ctl.c =================================================================== --- /dev/null +++ linux-2.6.30-rc4/drivers/md/dm-ioband-ctl.c @@ -0,0 +1,1358 @@ +/* + * Copyright (C) 2008-2009 VA Linux Systems Japan K.K. + * Authors: Hirokazu Takahashi <taka@xxxxxxxxxxxxx> + * Ryo Tsuruta <ryov@xxxxxxxxxxxxx> + * + * I/O bandwidth control + * + * Some blktrace messages were added by Alan D. Brunelle <Alan.Brunelle@xxxxxx> + * + * This file is released under the GPL. + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/bio.h> +#include <linux/slab.h> +#include <linux/workqueue.h> +#include <linux/rbtree.h> +#include <linux/blktrace_api.h> +#include "dm.h" +#include "md.h" +#include "dm-ioband.h" + +#define POLICY_PARAM_START 6 +#define POLICY_PARAM_DELIM "=:," + +#define num_issued(dp) \ + (dp->g_issued[BLK_RW_SYNC] + dp->g_issued[BLK_RW_ASYNC]) + +static LIST_HEAD(ioband_device_list); +/* to protect ioband_device_list */ +static DEFINE_SPINLOCK(ioband_devicelist_lock); + +static void suspend_ioband_device(struct ioband_device *, unsigned long, int); +static void resume_ioband_device(struct ioband_device *); +static void ioband_conduct(struct work_struct *); +static void ioband_hold_bio(struct ioband_group *, struct bio *); +static struct bio *ioband_pop_bio(struct ioband_group *); +static int ioband_set_param(struct ioband_group *, char *, char *); +static int ioband_group_attach(struct ioband_group *, int, char *); +static int ioband_group_type_select(struct ioband_group *, char *); + +static void do_nothing(void) {} + +static int policy_init(struct ioband_device *dp, char *name, + int argc, char **argv) +{ + struct policy_type *p; + struct ioband_group *gp; + unsigned long flags; + int r; + + for (p = dm_ioband_policy_type; p->p_name; p++) { + if (!strcmp(name, p->p_name)) + break; + } + if (!p->p_name) + return -EINVAL; + + spin_lock_irqsave(&dp->g_lock, flags); + if (dp->g_policy == p) { + /* do nothing if the same policy is already set */ + spin_unlock_irqrestore(&dp->g_lock, flags); + return 0; + } + + suspend_ioband_device(dp, flags, 1); + list_for_each_entry(gp, &dp->g_groups, c_list) + dp->g_group_dtr(gp); + + /* switch to the new policy */ + dp->g_policy = p; + r = p->p_policy_init(dp, argc, argv); + if (!r) { + if (!dp->g_hold_bio) + dp->g_hold_bio = ioband_hold_bio; + if (!dp->g_pop_bio) + dp->g_pop_bio = ioband_pop_bio; + + list_for_each_entry(gp, &dp->g_groups, c_list) + dp->g_group_ctr(gp, NULL); + } + resume_ioband_device(dp); + spin_unlock_irqrestore(&dp->g_lock, flags); + return r; +} + +static struct ioband_device *alloc_ioband_device(char *name, + int io_throttle, int io_limit) +{ + struct ioband_device *dp, *new_dp; + unsigned long flags; + + new_dp = kzalloc(sizeof(struct ioband_device), GFP_KERNEL); + if (!new_dp) + return NULL; + + /* + * Prepare its own workqueue as generic_make_request() may + * potentially block the workqueue when submitting BIOs. + */ + new_dp->g_ioband_wq = create_workqueue("kioband"); + if (!new_dp->g_ioband_wq) { + kfree(new_dp); + return NULL; + } + + spin_lock_irqsave(&ioband_devicelist_lock, flags); + list_for_each_entry(dp, &ioband_device_list, g_list) { + if (!strcmp(dp->g_name, name)) { + dp->g_ref++; + spin_unlock_irqrestore(&ioband_devicelist_lock, flags); + destroy_workqueue(new_dp->g_ioband_wq); + kfree(new_dp); + return dp; + } + } + + INIT_DELAYED_WORK(&new_dp->g_conductor, ioband_conduct); + INIT_LIST_HEAD(&new_dp->g_groups); + INIT_LIST_HEAD(&new_dp->g_list); + spin_lock_init(&new_dp->g_lock); + mutex_init(&new_dp->g_lock_device); + bio_list_init(&new_dp->g_urgent_bios); + new_dp->g_io_throttle = io_throttle; + new_dp->g_io_limit = io_limit; + new_dp->g_issued[BLK_RW_SYNC] = 0; + new_dp->g_issued[BLK_RW_ASYNC] = 0; + new_dp->g_blocked = 0; + new_dp->g_ref = 1; + new_dp->g_flags = 0; + strlcpy(new_dp->g_name, name, sizeof(new_dp->g_name)); + new_dp->g_policy = NULL; + new_dp->g_hold_bio = NULL; + new_dp->g_pop_bio = NULL; + init_waitqueue_head(&new_dp->g_waitq); + init_waitqueue_head(&new_dp->g_waitq_suspend); + init_waitqueue_head(&new_dp->g_waitq_flush); + list_add_tail(&new_dp->g_list, &ioband_device_list); + + spin_unlock_irqrestore(&ioband_devicelist_lock, flags); + return new_dp; +} + +static void release_ioband_device(struct ioband_device *dp) +{ + unsigned long flags; + + spin_lock_irqsave(&ioband_devicelist_lock, flags); + dp->g_ref--; + if (dp->g_ref > 0) { + spin_unlock_irqrestore(&ioband_devicelist_lock, flags); + return; + } + list_del(&dp->g_list); + spin_unlock_irqrestore(&ioband_devicelist_lock, flags); + destroy_workqueue(dp->g_ioband_wq); + kfree(dp); +} + +static int is_ioband_device_flushed(struct ioband_device *dp, + int wait_completion) +{ + struct ioband_group *gp; + + if (wait_completion && num_issued(dp) > 0) + return 0; + if (dp->g_blocked || waitqueue_active(&dp->g_waitq)) + return 0; + list_for_each_entry(gp, &dp->g_groups, c_list) + if (waitqueue_active(&gp->c_waitq)) + return 0; + return 1; +} + +static void suspend_ioband_device(struct ioband_device *dp, + unsigned long flags, int wait_completion) +{ + struct ioband_group *gp; + + /* block incoming bios */ + set_device_suspended(dp); + + /* wake up all blocked processes and go down all ioband groups */ + wake_up_all(&dp->g_waitq); + list_for_each_entry(gp, &dp->g_groups, c_list) { + if (!is_group_down(gp)) { + set_group_down(gp); + set_group_need_up(gp); + } + wake_up_all(&gp->c_waitq); + } + + /* flush the already mapped bios */ + spin_unlock_irqrestore(&dp->g_lock, flags); + queue_delayed_work(dp->g_ioband_wq, &dp->g_conductor, 0); + flush_workqueue(dp->g_ioband_wq); + + /* wait for all processes to wake up and bios to release */ + spin_lock_irqsave(&dp->g_lock, flags); + wait_event_lock_irq(dp->g_waitq_flush, + is_ioband_device_flushed(dp, wait_completion), + dp->g_lock, do_nothing()); +} + +static void resume_ioband_device(struct ioband_device *dp) +{ + struct ioband_group *gp; + + /* go up ioband groups */ + list_for_each_entry(gp, &dp->g_groups, c_list) { + if (group_need_up(gp)) { + clear_group_need_up(gp); + clear_group_down(gp); + } + } + + /* accept incoming bios */ + wake_up_all(&dp->g_waitq_suspend); + clear_device_suspended(dp); +} + +static struct ioband_group *ioband_group_find(struct ioband_group *head, int id) +{ + struct rb_node *node = head->c_group_root.rb_node; + + while (node) { + struct ioband_group *p = + container_of(node, struct ioband_group, c_group_node); + + if (p->c_id == id || id == IOBAND_ID_ANY) + return p; + node = (id < p->c_id) ? node->rb_left : node->rb_right; + } + return NULL; +} + +static void ioband_group_add_node(struct rb_root *root, struct ioband_group *gp) +{ + struct rb_node **node = &root->rb_node, *parent = NULL; + struct ioband_group *p; + + while (*node) { + p = container_of(*node, struct ioband_group, c_group_node); + parent = *node; + node = (gp->c_id < p->c_id) ? + &(*node)->rb_left : &(*node)->rb_right; + } + + rb_link_node(&gp->c_group_node, parent, node); + rb_insert_color(&gp->c_group_node, root); +} + +static int ioband_group_init(struct ioband_group *gp, + struct ioband_group *head, + struct ioband_device *dp, int id, char *param) +{ + unsigned long flags; + int r; + + INIT_LIST_HEAD(&gp->c_list); + bio_list_init(&gp->c_blocked_bios); + bio_list_init(&gp->c_prio_bios); + gp->c_id = id; /* should be verified */ + gp->c_blocked = 0; + gp->c_prio_blocked = 0; + memset(gp->c_stat, 0, sizeof(gp->c_stat)); + init_waitqueue_head(&gp->c_waitq); + gp->c_flags = 0; + gp->c_group_root = RB_ROOT; + gp->c_banddev = dp; + + spin_lock_irqsave(&dp->g_lock, flags); + if (head && ioband_group_find(head, id)) { + spin_unlock_irqrestore(&dp->g_lock, flags); + DMWARN("ioband_group: id=%d already exists.", id); + return -EEXIST; + } + + list_add_tail(&gp->c_list, &dp->g_groups); + + r = dp->g_group_ctr(gp, param); + if (r) { + list_del(&gp->c_list); + spin_unlock_irqrestore(&dp->g_lock, flags); + return r; + } + + if (head) { + ioband_group_add_node(&head->c_group_root, gp); + gp->c_dev = head->c_dev; + gp->c_target = head->c_target; + } + + spin_unlock_irqrestore(&dp->g_lock, flags); + + return 0; +} + +static void ioband_group_release(struct ioband_group *head, + struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + + list_del(&gp->c_list); + if (head) + rb_erase(&gp->c_group_node, &head->c_group_root); + dp->g_group_dtr(gp); + kfree(gp); +} + +static void ioband_group_destroy_all(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + struct ioband_group *p; + unsigned long flags; + + spin_lock_irqsave(&dp->g_lock, flags); + while ((p = ioband_group_find(gp, IOBAND_ID_ANY))) + ioband_group_release(gp, p); + ioband_group_release(NULL, gp); + spin_unlock_irqrestore(&dp->g_lock, flags); +} + +static void ioband_group_stop_all(struct ioband_group *head, int suspend) +{ + struct ioband_device *dp = head->c_banddev; + struct ioband_group *p; + struct rb_node *node; + unsigned long flags; + + spin_lock_irqsave(&dp->g_lock, flags); + for (node = rb_first(&head->c_group_root); node; node = rb_next(node)) { + p = rb_entry(node, struct ioband_group, c_group_node); + set_group_down(p); + if (suspend) + set_group_suspended(p); + } + set_group_down(head); + if (suspend) + set_group_suspended(head); + spin_unlock_irqrestore(&dp->g_lock, flags); + queue_delayed_work(dp->g_ioband_wq, &dp->g_conductor, 0); + flush_workqueue(dp->g_ioband_wq); +} + +static void ioband_group_resume_all(struct ioband_group *head) +{ + struct ioband_device *dp = head->c_banddev; + struct ioband_group *p; + struct rb_node *node; + unsigned long flags; + + spin_lock_irqsave(&dp->g_lock, flags); + for (node = rb_first(&head->c_group_root); node; node = rb_next(node)) { + p = rb_entry(node, struct ioband_group, c_group_node); + clear_group_down(p); + clear_group_suspended(p); + } + clear_group_down(head); + clear_group_suspended(head); + spin_unlock_irqrestore(&dp->g_lock, flags); +} + +static int split_string(char *s, long *id, char **v) +{ + char *p, *q; + int r = 0; + + *id = IOBAND_ID_ANY; + p = strsep(&s, POLICY_PARAM_DELIM); + q = strsep(&s, POLICY_PARAM_DELIM); + if (!q) { + *v = p; + } else { + r = strict_strtol(p, 0, id); + *v = q; + } + return r; +} + +/* + * Create a new band device: + * parameters: <device> <device-group-id> <io_throttle> <io_limit> + * <type> <policy> <policy-param...> <group-id:group-param...> + */ +static int ioband_ctr(struct dm_target *ti, unsigned argc, char **argv) +{ + struct ioband_group *gp; + struct ioband_device *dp; + struct dm_dev *dev; + int io_throttle; + int io_limit; + int i, r, start; + long val, id; + char *param, *s; + + if (argc < POLICY_PARAM_START) { + ti->error = "Requires " __stringify(POLICY_PARAM_START) + " or more arguments"; + return -EINVAL; + } + + if (strlen(argv[1]) > IOBAND_NAME_MAX) { + ti->error = "Ioband device name is too long"; + return -EINVAL; + } + + r = strict_strtol(argv[2], 0, &val); + if (r || val < 0 || val > SHORT_MAX) { + ti->error = "Invalid io_throttle"; + return -EINVAL; + } + io_throttle = (val == 0) ? DEFAULT_IO_THROTTLE : val; + + r = strict_strtol(argv[3], 0, &val); + if (r || val < 0 || val > SHORT_MAX) { + ti->error = "Invalid io_limit"; + return -EINVAL; + } + io_limit = val; + + r = dm_get_device(ti, argv[0], 0, ti->len, + dm_table_get_mode(ti->table), &dev); + if (r) { + ti->error = "Device lookup failed"; + return r; + } + + if (io_limit == 0) { + struct request_queue *q; + + q = bdev_get_queue(dev->bdev); + if (!q) { + ti->error = "Can't get queue size"; + r = -ENXIO; + goto release_dm_device; + } + io_limit = q->nr_requests; + } + + if (io_limit < io_throttle) + io_limit = io_throttle; + + dp = alloc_ioband_device(argv[1], io_throttle, io_limit); + if (!dp) { + ti->error = "Cannot create ioband device"; + r = -EINVAL; + goto release_dm_device; + } + + mutex_lock(&dp->g_lock_device); + r = policy_init(dp, argv[POLICY_PARAM_START - 1], + argc - POLICY_PARAM_START, &argv[POLICY_PARAM_START]); + if (r) { + ti->error = "Invalid policy parameter"; + goto release_ioband_device; + } + + gp = kzalloc(sizeof(struct ioband_group), GFP_KERNEL); + if (!gp) { + ti->error = "Cannot allocate memory for ioband group"; + r = -ENOMEM; + goto release_ioband_device; + } + + ti->private = gp; + gp->c_target = ti; + gp->c_dev = dev; + + /* Find a default group parameter */ + for (start = POLICY_PARAM_START; start < argc; start++) { + s = strpbrk(argv[start], POLICY_PARAM_DELIM); + if (s == argv[start]) + break; + } + param = (start < argc) ? &argv[start][1] : NULL; + + /* Create a default ioband group */ + r = ioband_group_init(gp, NULL, dp, IOBAND_ID_ANY, param); + if (r) { + kfree(gp); + ti->error = "Cannot create default ioband group"; + goto release_ioband_device; + } + + r = ioband_group_type_select(gp, argv[4]); + if (r) { + ti->error = "Cannot set ioband group type"; + goto release_ioband_group; + } + + /* Create sub ioband groups */ + for (i = start + 1; i < argc; i++) { + r = split_string(argv[i], &id, ¶m); + if (r) { + ti->error = "Invalid ioband group parameter"; + goto release_ioband_group; + } + r = ioband_group_attach(gp, id, param); + if (r) { + ti->error = "Cannot create ioband group"; + goto release_ioband_group; + } + } + mutex_unlock(&dp->g_lock_device); + return 0; + +release_ioband_group: + ioband_group_destroy_all(gp); +release_ioband_device: + mutex_unlock(&dp->g_lock_device); + release_ioband_device(dp); +release_dm_device: + dm_put_device(ti, dev); + return r; +} + +static void ioband_dtr(struct dm_target *ti) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + + mutex_lock(&dp->g_lock_device); + ioband_group_stop_all(gp, 0); + cancel_delayed_work_sync(&dp->g_conductor); + dm_put_device(ti, gp->c_dev); + ioband_group_destroy_all(gp); + mutex_unlock(&dp->g_lock_device); + release_ioband_device(dp); +} + +static void ioband_hold_bio(struct ioband_group *gp, struct bio *bio) +{ + /* Todo: The list should be split into a sync list and an async list */ + bio_list_add(&gp->c_blocked_bios, bio); +} + +static struct bio *ioband_pop_bio(struct ioband_group *gp) +{ + return bio_list_pop(&gp->c_blocked_bios); +} + +static int is_urgent_bio(struct bio *bio) +{ + struct page *page = bio_iovec_idx(bio, 0)->bv_page; + /* + * ToDo: A new flag should be added to struct bio, which indicates + * it contains urgent I/O requests. + */ + if (!PageReclaim(page)) + return 0; + if (PageSwapCache(page)) + return 2; + return 1; +} + +static inline int device_should_block(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + + if (is_group_down(gp)) + return 0; + if (is_device_blocked(dp)) + return 1; + if (dp->g_blocked >= dp->g_io_limit * 2) { + set_device_blocked(dp); + return 1; + } + return 0; +} + +static inline int group_should_block(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + + if (is_group_down(gp)) + return 0; + if (is_group_blocked(gp)) + return 1; + if (dp->g_should_block(gp)) { + set_group_blocked(gp); + return 1; + } + return 0; +} + +static void prevent_burst_bios(struct ioband_group *gp, struct bio *bio) +{ + struct ioband_device *dp = gp->c_banddev; + + if (current->flags & PF_KTHREAD || is_urgent_bio(bio)) { + /* + * Kernel threads shouldn't be blocked easily since each of + * them may handle BIOs for several groups on several + * partitions. + */ + wait_event_lock_irq(dp->g_waitq, !device_should_block(gp), + dp->g_lock, do_nothing()); + } else { + wait_event_lock_irq(gp->c_waitq, !group_should_block(gp), + dp->g_lock, do_nothing()); + } +} + +static inline int should_pushback_bio(struct ioband_group *gp) +{ + return is_group_suspended(gp) && dm_noflush_suspending(gp->c_target); +} + +static inline bool bio_is_sync(struct bio *bio) +{ + /* Must be the same condition as rw_is_sync() in blkdev.h */ + return !bio_data_dir(bio) || bio_sync(bio); +} + +static inline int prepare_to_issue(struct ioband_group *gp, struct bio *bio) +{ + struct ioband_device *dp = gp->c_banddev; + + dp->g_issued[bio_is_sync(bio)]++; + return dp->g_prepare_bio(gp, bio, 0); +} + +static inline int room_for_bio(struct ioband_device *dp) +{ + return dp->g_issued[BLK_RW_SYNC] < dp->g_io_limit + || dp->g_issued[BLK_RW_ASYNC] < dp->g_io_limit; +} + +static void hold_bio(struct ioband_group *gp, struct bio *bio) +{ + struct ioband_device *dp = gp->c_banddev; + + dp->g_blocked++; + if (is_urgent_bio(bio)) { + /* + * ToDo: + * When barrier mode is supported, write bios sharing the same + * file system with the currnt one would be all moved + * to g_urgent_bios list. + * You don't have to care about barrier handling if the bio + * is for swapping. + */ + dp->g_prepare_bio(gp, bio, IOBAND_URGENT); + bio_list_add(&dp->g_urgent_bios, bio); + /* TODO: blk_add_trace_msg will be replaced by TRACE_EVENT */ + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s hold_urg %d", dp->g_name, + dp->g_blocked); + } else { + gp->c_blocked++; + dp->g_hold_bio(gp, bio); + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s hold_nrm %d", dp->g_name, + gp->c_blocked); + } +} + +static inline int room_for_bio_sync(struct ioband_device *dp, int sync) +{ + return dp->g_issued[sync] < dp->g_io_limit; +} + +static void push_prio_bio(struct ioband_group *gp, struct bio *bio, int sync) +{ + if (bio_list_empty(&gp->c_prio_bios)) + set_prio_queue(gp, sync); + bio_list_add(&gp->c_prio_bios, bio); + gp->c_prio_blocked++; +} + +static struct bio *pop_prio_bio(struct ioband_group *gp) +{ + struct bio *bio = bio_list_pop(&gp->c_prio_bios); + + if (bio_list_empty(&gp->c_prio_bios)) + clear_prio_queue(gp); + + if (bio) + gp->c_prio_blocked--; + return bio; +} + +static int make_issue_list(struct ioband_group *gp, struct bio *bio, + struct bio_list *issue_list, + struct bio_list *pushback_list) +{ + struct ioband_device *dp = gp->c_banddev; + + dp->g_blocked--; + gp->c_blocked--; + if (!gp->c_blocked && is_group_blocked(gp)) { + clear_group_blocked(gp); + wake_up_all(&gp->c_waitq); + } + if (should_pushback_bio(gp)) { + bio_list_add(pushback_list, bio); + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s add_pback %d %d", dp->g_name, + dp->g_blocked, gp->c_blocked); + } else { + int rw = bio_data_dir(bio); + + gp->c_stat[rw].deferred++; + gp->c_stat[rw].sectors += bio_sectors(bio); + bio_list_add(issue_list, bio); + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s add_iss %d %d", dp->g_name, + dp->g_blocked, gp->c_blocked); + } + return prepare_to_issue(gp, bio); +} + +static void release_urgent_bios(struct ioband_device *dp, + struct bio_list *issue_list, + struct bio_list *pushback_list) +{ + struct bio *bio; + + if (bio_list_empty(&dp->g_urgent_bios)) + return; + while (room_for_bio_sync(dp, BLK_RW_ASYNC)) { + bio = bio_list_pop(&dp->g_urgent_bios); + if (!bio) + return; + dp->g_blocked--; + dp->g_issued[bio_is_sync(bio)]++; + bio_list_add(issue_list, bio); + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s urg_add_iss %d", dp->g_name, + dp->g_blocked); + } +} + +static int release_prio_bios(struct ioband_group *gp, + struct bio_list *issue_list, + struct bio_list *pushback_list) +{ + struct ioband_device *dp = gp->c_banddev; + struct bio *bio; + int sync; + int ret; + + if (bio_list_empty(&gp->c_prio_bios)) + return R_OK; + sync = prio_queue_sync(gp); + while (gp->c_prio_blocked) { + if (!dp->g_can_submit(gp)) + return R_BLOCK; + if (!room_for_bio_sync(dp, sync)) + return R_OK; + bio = pop_prio_bio(gp); + if (!bio) + return R_OK; + ret = make_issue_list(gp, bio, issue_list, pushback_list); + if (ret) + return ret; + } + return R_OK; +} + +static int release_norm_bios(struct ioband_group *gp, + struct bio_list *issue_list, + struct bio_list *pushback_list) +{ + struct ioband_device *dp = gp->c_banddev; + struct bio *bio; + int sync, ret; + + while (gp->c_blocked - gp->c_prio_blocked) { + if (!dp->g_can_submit(gp)) + return R_BLOCK; + if (!room_for_bio(dp)) + return R_OK; + bio = dp->g_pop_bio(gp); + if (!bio) + return R_OK; + + sync = bio_is_sync(bio); + if (!room_for_bio_sync(dp, sync)) { + push_prio_bio(gp, bio, sync); + continue; + } + ret = make_issue_list(gp, bio, issue_list, pushback_list); + if (ret) + return ret; + } + return R_OK; +} + +static inline int release_bios(struct ioband_group *gp, + struct bio_list *issue_list, + struct bio_list *pushback_list) +{ + int ret = release_prio_bios(gp, issue_list, pushback_list); + if (ret) + return ret; + return release_norm_bios(gp, issue_list, pushback_list); +} + +static struct ioband_group *ioband_group_get(struct ioband_group *head, + struct bio *bio) +{ + struct ioband_group *gp; + + if (!head->c_type->t_getid) + return head; + + gp = ioband_group_find(head, head->c_type->t_getid(bio)); + + if (!gp) + gp = head; + return gp; +} + +/* + * Start to control the bandwidth once the number of uncompleted BIOs + * exceeds the value of "io_throttle". + */ +static int ioband_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + struct io_context *ioc; + unsigned long flags; + int direct; + + spin_lock_irqsave(&dp->g_lock, flags); + + /* + * The device is suspended while some of the ioband device + * configurations are being changed. + */ + if (is_device_suspended(dp)) + wait_event_lock_irq(dp->g_waitq_suspend, + !is_device_suspended(dp), dp->g_lock, + do_nothing()); + + gp = ioband_group_get(gp, bio); + if (should_pushback_bio(gp)) { + spin_unlock_irqrestore(&dp->g_lock, flags); + return DM_MAPIO_REQUEUE; + } + + bio->bi_bdev = gp->c_dev->bdev; + bio->bi_sector -= ti->begin; + direct = bio_data_dir(bio); + + /* + * RT IOs are always dispatched immediately, regardless of the + * assigned bandwidth, and it can cause other processes to be + * starved for IO. Some sort of limitaion for RT IOs is + * probably needed. + */ + ioc = current->io_context; + if (ioc && IOPRIO_PRIO_CLASS(ioc->ioprio) == IOPRIO_CLASS_RT) { + dp->g_issued[bio_is_sync(bio)]++; + gp->c_stat[direct].immediate++; + gp->c_stat[direct].sectors += bio_sectors(bio); + spin_unlock_irqrestore(&dp->g_lock, flags); + return DM_MAPIO_REMAPPED; + } + prevent_burst_bios(gp, bio); + + if (!gp->c_blocked && room_for_bio_sync(dp, bio_is_sync(bio))) { + if (dp->g_can_submit(gp)) { + prepare_to_issue(gp, bio); + gp->c_stat[direct].immediate++; + gp->c_stat[direct].sectors += bio_sectors(bio); + spin_unlock_irqrestore(&dp->g_lock, flags); + return DM_MAPIO_REMAPPED; + } else if (!dp->g_blocked && num_issued(dp) == 0) { + DMDEBUG("%s: token expired gp:%p", __func__, gp); + queue_delayed_work(dp->g_ioband_wq, + &dp->g_conductor, 1); + } + } + hold_bio(gp, bio); + spin_unlock_irqrestore(&dp->g_lock, flags); + + return DM_MAPIO_SUBMITTED; +} + +/* + * Select the best group to resubmit its BIOs. + */ +static struct ioband_group *choose_best_group(struct ioband_device *dp) +{ + struct ioband_group *gp; + struct ioband_group *best = NULL; + int highest = 0; + int pri; + + /* Todo: The algorithm should be optimized. + * It would be better to use rbtree. + */ + list_for_each_entry(gp, &dp->g_groups, c_list) { + if (!gp->c_blocked || !room_for_bio(dp)) + continue; + if (gp->c_blocked == gp->c_prio_blocked && + !room_for_bio_sync(dp, prio_queue_sync(gp))) { + continue; + } + pri = dp->g_can_submit(gp); + if (pri > highest) { + highest = pri; + best = gp; + } + } + + return best; +} + +/* + * This function is called right after it becomes able to resubmit BIOs. + * It selects the best BIOs and passes them to the underlying layer. + */ +static void ioband_conduct(struct work_struct *work) +{ + struct ioband_device *dp = + container_of(work, struct ioband_device, g_conductor.work); + struct ioband_group *gp = NULL; + struct bio *bio; + unsigned long flags; + struct bio_list issue_list, pushback_list; + + bio_list_init(&issue_list); + bio_list_init(&pushback_list); + + spin_lock_irqsave(&dp->g_lock, flags); + release_urgent_bios(dp, &issue_list, &pushback_list); + if (dp->g_blocked) { + gp = choose_best_group(dp); + if (gp && + release_bios(gp, &issue_list, &pushback_list) == R_YIELD) + queue_delayed_work(dp->g_ioband_wq, + &dp->g_conductor, 0); + } + + if (is_device_blocked(dp) && dp->g_blocked < dp->g_io_limit * 2) { + clear_device_blocked(dp); + wake_up_all(&dp->g_waitq); + } + + if (dp->g_blocked && + room_for_bio_sync(dp, BLK_RW_SYNC) && + room_for_bio_sync(dp, BLK_RW_ASYNC) && + bio_list_empty(&issue_list) && bio_list_empty(&pushback_list) && + dp->g_restart_bios(dp)) { + DMDEBUG("%s: token expired dp:%p issued(%d,%d) g_blocked(%d)", + __func__, dp, + dp->g_issued[BLK_RW_SYNC], dp->g_issued[BLK_RW_ASYNC], + dp->g_blocked); + queue_delayed_work(dp->g_ioband_wq, &dp->g_conductor, 0); + } + + spin_unlock_irqrestore(&dp->g_lock, flags); + + while ((bio = bio_list_pop(&issue_list))) { + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s pop_iss", dp->g_name); + generic_make_request(bio); + } + + while ((bio = bio_list_pop(&pushback_list))) { + blk_add_trace_msg(bdev_get_queue(bio->bi_bdev), + "ioband %s pop_pback", dp->g_name); + bio_endio(bio, -EIO); + } +} + +static int ioband_end_io(struct dm_target *ti, struct bio *bio, + int error, union map_info *map_context) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + unsigned long flags; + int r = error; + + /* + * XXX: A new error code for device mapper devices should be used + * rather than EIO. + */ + if (error == -EIO && should_pushback_bio(gp)) { + /* This ioband device is suspending */ + r = DM_ENDIO_REQUEUE; + } + /* + * Todo: The algorithm should be optimized to eliminate the spinlock. + */ + spin_lock_irqsave(&dp->g_lock, flags); + dp->g_issued[bio_is_sync(bio)]--; + + /* + * Todo: It would be better to introduce high/low water marks here + * not to kick the workqueues so often. + */ + if (dp->g_blocked) + queue_delayed_work(dp->g_ioband_wq, &dp->g_conductor, 0); + else if (is_device_suspended(dp) && num_issued(dp) == 0) + wake_up_all(&dp->g_waitq_flush); + spin_unlock_irqrestore(&dp->g_lock, flags); + return r; +} + +static void ioband_presuspend(struct dm_target *ti) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + + mutex_lock(&dp->g_lock_device); + ioband_group_stop_all(gp, 1); + mutex_unlock(&dp->g_lock_device); +} + +static void ioband_resume(struct dm_target *ti) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + + mutex_lock(&dp->g_lock_device); + ioband_group_resume_all(gp); + mutex_unlock(&dp->g_lock_device); +} + +static void ioband_group_status(struct ioband_group *gp, int *szp, + char *result, unsigned maxlen) +{ + struct ioband_group_stat *stat; + int i, sz = *szp; /* used in DMEMIT() */ + + DMEMIT(" %d", gp->c_id); + for (i = 0; i < 2; i++) { + stat = &gp->c_stat[i]; + DMEMIT(" %lu %lu %lu", + stat->immediate + stat->deferred, stat->deferred, + stat->sectors); + } + *szp = sz; +} + +static int ioband_status(struct dm_target *ti, status_type_t type, + char *result, unsigned maxlen) +{ + struct ioband_group *gp = ti->private, *p; + struct ioband_device *dp = gp->c_banddev; + struct rb_node *node; + int sz = 0; /* used in DMEMIT() */ + unsigned long flags; + + mutex_lock(&dp->g_lock_device); + + switch (type) { + case STATUSTYPE_INFO: + spin_lock_irqsave(&dp->g_lock, flags); + DMEMIT("%s", dp->g_name); + ioband_group_status(gp, &sz, result, maxlen); + for (node = rb_first(&gp->c_group_root); node; + node = rb_next(node)) { + p = rb_entry(node, struct ioband_group, c_group_node); + ioband_group_status(p, &sz, result, maxlen); + } + spin_unlock_irqrestore(&dp->g_lock, flags); + break; + + case STATUSTYPE_TABLE: + spin_lock_irqsave(&dp->g_lock, flags); + DMEMIT("%s %s %d %d %s %s", + gp->c_dev->name, dp->g_name, + dp->g_io_throttle, dp->g_io_limit, + gp->c_type->t_name, dp->g_policy->p_name); + dp->g_show(gp, &sz, result, maxlen); + spin_unlock_irqrestore(&dp->g_lock, flags); + break; + } + + mutex_unlock(&dp->g_lock_device); + return 0; +} + +static int ioband_group_type_select(struct ioband_group *gp, char *name) +{ + struct ioband_device *dp = gp->c_banddev; + struct group_type *t; + unsigned long flags; + + for (t = dm_ioband_group_type; (t->t_name); t++) { + if (!strcmp(name, t->t_name)) + break; + } + if (!t->t_name) { + DMWARN("ioband type select: %s isn't supported.", name); + return -EINVAL; + } + spin_lock_irqsave(&dp->g_lock, flags); + if (!RB_EMPTY_ROOT(&gp->c_group_root)) { + spin_unlock_irqrestore(&dp->g_lock, flags); + return -EBUSY; + } + gp->c_type = t; + spin_unlock_irqrestore(&dp->g_lock, flags); + + return 0; +} + +static int ioband_set_param(struct ioband_group *gp, char *cmd, char *value) +{ + struct ioband_device *dp = gp->c_banddev; + char *val_str; + long id; + unsigned long flags; + int r; + + r = split_string(value, &id, &val_str); + if (r) + return r; + + spin_lock_irqsave(&dp->g_lock, flags); + if (id != IOBAND_ID_ANY) { + gp = ioband_group_find(gp, id); + if (!gp) { + spin_unlock_irqrestore(&dp->g_lock, flags); + DMWARN("ioband_set_param: id=%ld not found.", id); + return -EINVAL; + } + } + r = dp->g_set_param(gp, cmd, val_str); + spin_unlock_irqrestore(&dp->g_lock, flags); + return r; +} + +static int ioband_group_attach(struct ioband_group *gp, int id, char *param) +{ + struct ioband_device *dp = gp->c_banddev; + struct ioband_group *sub_gp; + int r; + + if (id < 0) { + DMWARN("ioband_group_attach: invalid id:%d", id); + return -EINVAL; + } + if (!gp->c_type->t_getid) { + DMWARN("ioband_group_attach: " + "no ioband group type is specified"); + return -EINVAL; + } + + sub_gp = kzalloc(sizeof(struct ioband_group), GFP_KERNEL); + if (!sub_gp) + return -ENOMEM; + + r = ioband_group_init(sub_gp, gp, dp, id, param); + if (r < 0) { + kfree(sub_gp); + return r; + } + return 0; +} + +static int ioband_group_detach(struct ioband_group *gp, int id) +{ + struct ioband_device *dp = gp->c_banddev; + struct ioband_group *sub_gp; + unsigned long flags; + + if (id < 0) { + DMWARN("ioband_group_detach: invalid id:%d", id); + return -EINVAL; + } + spin_lock_irqsave(&dp->g_lock, flags); + sub_gp = ioband_group_find(gp, id); + if (!sub_gp) { + spin_unlock_irqrestore(&dp->g_lock, flags); + DMWARN("ioband_group_detach: invalid id:%d", id); + return -EINVAL; + } + + /* + * Todo: Calling suspend_ioband_device() before releasing the + * ioband group has a large overhead. Need improvement. + */ + suspend_ioband_device(dp, flags, 0); + ioband_group_release(gp, sub_gp); + resume_ioband_device(dp); + spin_unlock_irqrestore(&dp->g_lock, flags); + return 0; +} + +/* + * Message parameters: + * "policy" <name> + * ex) + * "policy" "weight" + * "type" "none"|"pid"|"pgrp"|"node"|"cpuset"|"cgroup"|"user"|"gid" + * "io_throttle" <value> + * "io_limit" <value> + * "attach" <group id> + * "detach" <group id> + * "any-command" <group id>:<value> + * ex) + * "weight" 0:<value> + * "token" 24:<value> + */ +static int __ioband_message(struct dm_target *ti, unsigned argc, char **argv) +{ + struct ioband_group *gp = ti->private, *p; + struct ioband_device *dp = gp->c_banddev; + struct rb_node *node; + long val; + int r = 0; + unsigned long flags; + + if (argc == 1 && !strcmp(argv[0], "reset")) { + spin_lock_irqsave(&dp->g_lock, flags); + memset(gp->c_stat, 0, sizeof(gp->c_stat)); + for (node = rb_first(&gp->c_group_root); node; + node = rb_next(node)) { + p = rb_entry(node, struct ioband_group, c_group_node); + memset(p->c_stat, 0, sizeof(p->c_stat)); + } + spin_unlock_irqrestore(&dp->g_lock, flags); + return 0; + } + + if (argc != 2) { + DMWARN("Unrecognised band message received."); + return -EINVAL; + } + if (!strcmp(argv[0], "io_throttle")) { + r = strict_strtol(argv[1], 0, &val); + if (r || val < 0 || val > SHORT_MAX) + return -EINVAL; + if (val == 0) + val = DEFAULT_IO_THROTTLE; + spin_lock_irqsave(&dp->g_lock, flags); + if (val > dp->g_io_limit) { + spin_unlock_irqrestore(&dp->g_lock, flags); + return -EINVAL; + } + dp->g_io_throttle = val; + spin_unlock_irqrestore(&dp->g_lock, flags); + ioband_set_param(gp, argv[0], argv[1]); + return 0; + } else if (!strcmp(argv[0], "io_limit")) { + r = strict_strtol(argv[1], 0, &val); + if (r || val < 0 || val > SHORT_MAX) + return -EINVAL; + spin_lock_irqsave(&dp->g_lock, flags); + if (val == 0) { + struct request_queue *q; + + q = bdev_get_queue(gp->c_dev->bdev); + if (!q) { + spin_unlock_irqrestore(&dp->g_lock, flags); + return -ENXIO; + } + val = q->nr_requests; + } + if (val < dp->g_io_throttle) { + spin_unlock_irqrestore(&dp->g_lock, flags); + return -EINVAL; + } + dp->g_io_limit = val; + spin_unlock_irqrestore(&dp->g_lock, flags); + ioband_set_param(gp, argv[0], argv[1]); + return 0; + } else if (!strcmp(argv[0], "type")) { + return ioband_group_type_select(gp, argv[1]); + } else if (!strcmp(argv[0], "attach")) { + r = strict_strtol(argv[1], 0, &val); + if (r) + return r; + return ioband_group_attach(gp, val, NULL); + } else if (!strcmp(argv[0], "detach")) { + r = strict_strtol(argv[1], 0, &val); + if (r) + return r; + return ioband_group_detach(gp, val); + } else if (!strcmp(argv[0], "policy")) { + r = policy_init(dp, argv[1], 0, &argv[2]); + return r; + } else { + /* message anycommand <group-id>:<value> */ + r = ioband_set_param(gp, argv[0], argv[1]); + if (r < 0) + DMWARN("Unrecognised band message received."); + return r; + } + return 0; +} + +static int ioband_message(struct dm_target *ti, unsigned argc, char **argv) +{ + struct ioband_group *gp = ti->private; + struct ioband_device *dp = gp->c_banddev; + int r; + + mutex_lock(&dp->g_lock_device); + r = __ioband_message(ti, argc, argv); + mutex_unlock(&dp->g_lock_device); + return r; +} + +static int ioband_merge(struct dm_target *ti, struct bvec_merge_data *bvm, + struct bio_vec *biovec, int max_size) +{ + struct ioband_group *gp = ti->private; + struct request_queue *q = bdev_get_queue(gp->c_dev->bdev); + + if (!q->merge_bvec_fn) + return max_size; + + bvm->bi_bdev = gp->c_dev->bdev; + bvm->bi_sector -= ti->begin; + + return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); +} + +static struct target_type ioband_target = { + .name = "ioband", + .module = THIS_MODULE, + .version = {1, 11, 0}, + .ctr = ioband_ctr, + .dtr = ioband_dtr, + .map = ioband_map, + .end_io = ioband_end_io, + .presuspend = ioband_presuspend, + .resume = ioband_resume, + .status = ioband_status, + .message = ioband_message, + .merge = ioband_merge, +}; + +static int __init dm_ioband_init(void) +{ + int r; + + r = dm_register_target(&ioband_target); + if (r < 0) { + DMERR("register failed %d", r); + return r; + } + return r; +} + +static void __exit dm_ioband_exit(void) +{ + dm_unregister_target(&ioband_target); +} + +module_init(dm_ioband_init); +module_exit(dm_ioband_exit); + +MODULE_DESCRIPTION(DM_NAME " I/O bandwidth control"); +MODULE_AUTHOR("Hirokazu Takahashi <taka@xxxxxxxxxxxxx>, " + "Ryo Tsuruta <ryov@xxxxxxxxxxxxx"); +MODULE_LICENSE("GPL"); Index: linux-2.6.30-rc4/drivers/md/dm-ioband-policy.c =================================================================== --- /dev/null +++ linux-2.6.30-rc4/drivers/md/dm-ioband-policy.c @@ -0,0 +1,454 @@ +/* + * Copyright (C) 2008-2009 VA Linux Systems Japan K.K. + * + * I/O bandwidth control + * + * This file is released under the GPL. + */ +#include <linux/bio.h> +#include <linux/workqueue.h> +#include <linux/rbtree.h> +#include "dm.h" +#include "dm-ioband.h" + +/* + * The following functions determine when and which BIOs should + * be submitted to control the I/O flow. + * It is possible to add a new BIO scheduling policy with it. + */ + +/* + * Functions for weight balancing policy based on the number of I/Os. + */ +#define DEFAULT_WEIGHT 100 +#define DEFAULT_TOKENPOOL 2048 +#define DEFAULT_BUCKET 2 +#define IOBAND_IOPRIO_BASE 100 +#define TOKEN_BATCH_UNIT 20 +#define PROCEED_THRESHOLD 8 +#define LOCAL_ACTIVE_RATIO 8 +#define GLOBAL_ACTIVE_RATIO 16 +#define OVERCOMMIT_RATE 4 + +/* + * Calculate the effective number of tokens this group has. + */ +static int get_token(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + int token = gp->c_token; + int allowance = dp->g_epoch - gp->c_my_epoch; + + if (allowance) { + if (allowance > dp->g_carryover) + allowance = dp->g_carryover; + token += gp->c_token_initial * allowance; + } + if (is_group_down(gp)) + token += gp->c_token_initial * dp->g_carryover * 2; + + return token; +} + +/* + * Calculate the priority of a given group. + */ +static int iopriority(struct ioband_group *gp) +{ + return get_token(gp) * IOBAND_IOPRIO_BASE / gp->c_token_initial + 1; +} + +/* + * This function is called when all the active group on the same ioband + * device has used up their tokens. It makes a new global epoch so that + * all groups on this device will get freshly assigned tokens. + */ +static int make_global_epoch(struct ioband_device *dp) +{ + struct ioband_group *gp = dp->g_dominant; + + /* + * Don't make a new epoch if the dominant group still has a lot of + * tokens, except when the I/O load is low. + */ + if (gp) { + int iopri = iopriority(gp); + if (iopri * PROCEED_THRESHOLD > IOBAND_IOPRIO_BASE && + dp->g_issued[READ] + dp->g_issued[WRITE] >= + dp->g_io_throttle) + return 0; + } + + dp->g_epoch++; + DMDEBUG("make_epoch %d", dp->g_epoch); + + /* The leftover tokens will be used in the next epoch. */ + dp->g_token_extra = dp->g_token_left; + if (dp->g_token_extra < 0) + dp->g_token_extra = 0; + dp->g_token_left = dp->g_token_bucket; + + dp->g_expired = NULL; + dp->g_dominant = NULL; + + return 1; +} + +/* + * This function is called when this group has used up its own tokens. + * It will check whether it's possible to make a new epoch of this group. + */ +static inline int make_epoch(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + int allowance = dp->g_epoch - gp->c_my_epoch; + + if (!allowance) + return 0; + if (allowance > dp->g_carryover) + allowance = dp->g_carryover; + gp->c_my_epoch = dp->g_epoch; + return allowance; +} + +/* + * Check whether this group has tokens to issue an I/O. Return 0 if it + * doesn't have any, otherwise return the priority of this group. + */ +static int is_token_left(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + int allowance; + int delta; + int extra; + + if (gp->c_token > 0) + return iopriority(gp); + + if (is_group_down(gp)) { + gp->c_token = gp->c_token_initial; + return iopriority(gp); + } + allowance = make_epoch(gp); + if (!allowance) + return 0; + /* + * If this group has the right to get tokens for several epochs, + * give all of them to the group here. + */ + delta = gp->c_token_initial * allowance; + dp->g_token_left -= delta; + /* + * Give some extra tokens to this group when there have left unused + * tokens on this ioband device from the previous epoch. + */ + extra = dp->g_token_extra * gp->c_token_initial / + (dp->g_token_bucket - dp->g_token_extra / 2); + delta += extra; + gp->c_token += delta; + gp->c_consumed = 0; + + if (gp == dp->g_current) + dp->g_yield_mark += delta; + DMDEBUG("refill token: gp:%p token:%d->%d extra(%d) allowance(%d)", + gp, gp->c_token - delta, gp->c_token, extra, allowance); + if (gp->c_token > 0) + return iopriority(gp); + DMDEBUG("refill token: yet empty gp:%p token:%d", gp, gp->c_token); + return 0; +} + +/* + * Use tokens to issue an I/O. After the operation, the number of tokens left + * on this group may become negative value, which will be treated as debt. + */ +static int consume_token(struct ioband_group *gp, int count, int flag) +{ + struct ioband_device *dp = gp->c_banddev; + + if (gp->c_consumed * LOCAL_ACTIVE_RATIO < gp->c_token_initial && + gp->c_consumed * GLOBAL_ACTIVE_RATIO < dp->g_token_bucket) { + ; /* Do nothing unless this group is really active. */ + } else if (!dp->g_dominant || + get_token(gp) > get_token(dp->g_dominant)) { + /* + * Regard this group as the dominant group on this + * ioband device when it has larger number of tokens + * than those of the previous one. + */ + dp->g_dominant = gp; + } + if (dp->g_epoch == gp->c_my_epoch && + gp->c_token > 0 && gp->c_token - count <= 0) { + /* Remember the last group which used up its own tokens. */ + dp->g_expired = gp; + if (dp->g_dominant == gp) + dp->g_dominant = NULL; + } + + if (gp != dp->g_current) { + /* This group is the current already. */ + dp->g_current = gp; + dp->g_yield_mark = + gp->c_token - (TOKEN_BATCH_UNIT << dp->g_token_unit); + } + gp->c_token -= count; + gp->c_consumed += count; + if (gp->c_token <= dp->g_yield_mark && !(flag & IOBAND_URGENT)) { + /* + * Return-value 1 means that this policy requests dm-ioband + * to give a chance to another group to be selected since + * this group has already issued enough amount of I/Os. + */ + dp->g_current = NULL; + return R_YIELD; + } + /* + * Return-value 0 means that this policy allows dm-ioband to select + * this group to issue I/Os without a break. + */ + return R_OK; +} + +/* + * Consume one token on each I/O. + */ +static int prepare_token(struct ioband_group *gp, struct bio *bio, int flag) +{ + return consume_token(gp, 1, flag); +} + +/* + * Check if this group is able to receive a new bio. + */ +static int is_queue_full(struct ioband_group *gp) +{ + return gp->c_blocked >= gp->c_limit; +} + +static void set_weight(struct ioband_group *gp, int new) +{ + struct ioband_device *dp = gp->c_banddev; + struct ioband_group *p; + + dp->g_weight_total += (new - gp->c_weight); + gp->c_weight = new; + + if (dp->g_weight_total == 0) { + list_for_each_entry(p, &dp->g_groups, c_list) + p->c_token = p->c_token_initial = p->c_limit = 1; + } else { + list_for_each_entry(p, &dp->g_groups, c_list) { + p->c_token = p->c_token_initial = + dp->g_token_bucket * p->c_weight / + dp->g_weight_total + 1; + p->c_limit = dp->g_io_limit * 2 * p->c_weight / + dp->g_weight_total / OVERCOMMIT_RATE + 1; + } + } +} + +static void init_token_bucket(struct ioband_device *dp, + int token_bucket, int carryover) +{ + if (!token_bucket) + dp->g_token_bucket = (dp->g_io_limit * 2 * DEFAULT_BUCKET) << + dp->g_token_unit; + else + dp->g_token_bucket = token_bucket; + if (!carryover) + dp->g_carryover = (DEFAULT_TOKENPOOL << dp->g_token_unit) / + dp->g_token_bucket; + else + dp->g_carryover = carryover; + if (dp->g_carryover < 1) + dp->g_carryover = 1; + dp->g_token_left = 0; +} + +static int policy_weight_param(struct ioband_group *gp, char *cmd, char *value) +{ + struct ioband_device *dp = gp->c_banddev; + long val; + int r = 0, err; + + err = strict_strtol(value, 0, &val); + if (!strcmp(cmd, "weight")) { + if (!err && 0 < val && val <= SHORT_MAX) + set_weight(gp, val); + else + r = -EINVAL; + } else if (!strcmp(cmd, "token")) { + if (!err && 0 <= val && val <= INT_MAX) { + init_token_bucket(dp, val, 0); + set_weight(gp, gp->c_weight); + dp->g_token_extra = 0; + } else + r = -EINVAL; + } else if (!strcmp(cmd, "carryover")) { + if (!err && 0 <= val && val <= INT_MAX) { + init_token_bucket(dp, dp->g_token_bucket, val); + set_weight(gp, gp->c_weight); + dp->g_token_extra = 0; + } else + r = -EINVAL; + } else if (!strcmp(cmd, "io_limit")) { + init_token_bucket(dp, 0, 0); + set_weight(gp, gp->c_weight); + } else { + r = -EINVAL; + } + return r; +} + +static int policy_weight_ctr(struct ioband_group *gp, char *arg) +{ + struct ioband_device *dp = gp->c_banddev; + + if (!arg) + arg = __stringify(DEFAULT_WEIGHT); + gp->c_my_epoch = dp->g_epoch; + gp->c_weight = 0; + gp->c_consumed = 0; + return policy_weight_param(gp, "weight", arg); +} + +static void policy_weight_dtr(struct ioband_group *gp) +{ + struct ioband_device *dp = gp->c_banddev; + set_weight(gp, 0); + dp->g_dominant = NULL; + dp->g_expired = NULL; +} + +static void policy_weight_show(struct ioband_group *gp, int *szp, + char *result, unsigned maxlen) +{ + struct ioband_group *p; + struct ioband_device *dp = gp->c_banddev; + struct rb_node *node; + int sz = *szp; /* used in DMEMIT() */ + + DMEMIT(" %d :%d", dp->g_token_bucket, gp->c_weight); + + for (node = rb_first(&gp->c_group_root); node; node = rb_next(node)) { + p = rb_entry(node, struct ioband_group, c_group_node); + DMEMIT(" %d:%d", p->c_id, p->c_weight); + } + *szp = sz; +} + +/* + * <Method> <description> + * g_can_submit : To determine whether a given group has the right to + * submit BIOs. The larger the return value the higher the + * priority to submit. Zero means it has no right. + * g_prepare_bio : Called right before submitting each BIO. + * g_restart_bios : Called if this ioband device has some BIOs blocked but none + * of them can be submitted now. This method has to + * reinitialize the data to restart to submit BIOs and return + * 0 or 1. + * The return value 0 means that it has become able to submit + * them now so that this ioband device will continue its work. + * The return value 1 means that it is still unable to submit + * them so that this device will stop its work. And this + * policy module has to reactivate the device when it gets + * to be able to submit BIOs. + * g_hold_bio : To hold a given BIO until it is submitted. + * The default function is used when this method is undefined. + * g_pop_bio : To select and get the best BIO to submit. + * g_group_ctr : To initalize the policy own members of struct ioband_group. + * g_group_dtr : Called when struct ioband_group is removed. + * g_set_param : To update the policy own date. + * The parameters can be passed through "dmsetup message" + * command. + * g_should_block : Called every time this ioband device receive a BIO. + * Return 1 if a given group can't receive any more BIOs, + * otherwise return 0. + * g_show : Show the configuration. + */ +static int policy_weight_init(struct ioband_device *dp, int argc, char **argv) +{ + long val; + int r = 0; + + if (argc < 1) + val = 0; + else { + r = strict_strtol(argv[0], 0, &val); + if (r || val < 0 || val > INT_MAX) + return -EINVAL; + } + + dp->g_can_submit = is_token_left; + dp->g_prepare_bio = prepare_token; + dp->g_restart_bios = make_global_epoch; + dp->g_group_ctr = policy_weight_ctr; + dp->g_group_dtr = policy_weight_dtr; + dp->g_set_param = policy_weight_param; + dp->g_should_block = is_queue_full; + dp->g_show = policy_weight_show; + + dp->g_epoch = 0; + dp->g_weight_total = 0; + dp->g_current = NULL; + dp->g_dominant = NULL; + dp->g_expired = NULL; + dp->g_token_extra = 0; + dp->g_token_unit = 0; + init_token_bucket(dp, val, 0); + dp->g_token_left = dp->g_token_bucket; + + return 0; +} + +/* weight balancing policy based on the number of I/Os. --- End --- */ + +/* + * Functions for weight balancing policy based on I/O size. + * It just borrows a lot of functions from the regular weight balancing policy. + */ +static int w2_prepare_token(struct ioband_group *gp, struct bio *bio, int flag) +{ + /* Consume tokens depending on the size of a given bio. */ + return consume_token(gp, bio_sectors(bio), flag); +} + +static int w2_policy_weight_init(struct ioband_device *dp, + int argc, char **argv) +{ + long val; + int r = 0; + + if (argc < 1) + val = 0; + else { + r = strict_strtol(argv[0], 0, &val); + if (r || val < 0 || val > INT_MAX) + return -EINVAL; + } + + r = policy_weight_init(dp, argc, argv); + if (r < 0) + return r; + + dp->g_prepare_bio = w2_prepare_token; + dp->g_token_unit = PAGE_SHIFT - 9; + init_token_bucket(dp, val, 0); + dp->g_token_left = dp->g_token_bucket; + return 0; +} + +/* weight balancing policy based on I/O size. --- End --- */ + +static int policy_default_init(struct ioband_device *dp, int argc, char **argv) +{ + return policy_weight_init(dp, argc, argv); +} + +struct policy_type dm_ioband_policy_type[] = { + {"default", policy_default_init}, + {"weight", policy_weight_init}, + {"weight-iosize", w2_policy_weight_init}, + {NULL, policy_default_init} +}; Index: linux-2.6.30-rc4/drivers/md/dm-ioband-type.c =================================================================== --- /dev/null +++ linux-2.6.30-rc4/drivers/md/dm-ioband-type.c @@ -0,0 +1,76 @@ +/* + * Copyright (C) 2008-2009 VA Linux Systems Japan K.K. + * + * I/O bandwidth control + * + * This file is released under the GPL. + */ +#include <linux/bio.h> +#include "dm.h" +#include "dm-ioband.h" + +/* + * Any I/O bandwidth can be divided into several bandwidth groups, each of which + * has its own unique ID. The following functions are called to determine + * which group a given BIO belongs to and return the ID of the group. + */ + +/* ToDo: unsigned long value would be better for group ID */ + +static int ioband_process_id(struct bio *bio) +{ + /* + * This function will work for KVM and Xen. + */ + return (int)current->tgid; +} + +static int ioband_process_group(struct bio *bio) +{ + return (int)task_pgrp_nr(current); +} + +static int ioband_uid(struct bio *bio) +{ + return (int)current_uid(); +} + +static int ioband_gid(struct bio *bio) +{ + return (int)current_gid(); +} + +static int ioband_cpuset(struct bio *bio) +{ + return 0; /* not implemented yet */ +} + +static int ioband_node(struct bio *bio) +{ + return 0; /* not implemented yet */ +} + +static int ioband_cgroup(struct bio *bio) +{ + /* + * This function should return the ID of the cgroup which + * issued "bio". The ID of the cgroup which the current + * process belongs to won't be suitable ID for this purpose, + * since some BIOs will be handled by kernel threads like aio + * or pdflush on behalf of the process requesting the BIOs. + */ + return 0; /* not implemented yet */ +} + +struct group_type dm_ioband_group_type[] = { + {"none", NULL}, + {"pgrp", ioband_process_group}, + {"pid", ioband_process_id}, + {"node", ioband_node}, + {"cpuset", ioband_cpuset}, + {"cgroup", ioband_cgroup}, + {"user", ioband_uid}, + {"uid", ioband_uid}, + {"gid", ioband_gid}, + {NULL, NULL} +}; Index: linux-2.6.30-rc4/drivers/md/dm-ioband.h =================================================================== --- /dev/null +++ linux-2.6.30-rc4/drivers/md/dm-ioband.h @@ -0,0 +1,186 @@ +/* + * Copyright (C) 2008-2009 VA Linux Systems Japan K.K. + * + * I/O bandwidth control + * + * This file is released under the GPL. + */ + +#include <linux/version.h> +#include <linux/wait.h> + +#define DM_MSG_PREFIX "ioband" + +#define DEFAULT_IO_THROTTLE 4 +#define DEFAULT_IO_LIMIT 128 +#define IOBAND_NAME_MAX 31 +#define IOBAND_ID_ANY (-1) + +struct ioband_group; + +struct ioband_device { + struct list_head g_groups; + struct delayed_work g_conductor; + struct workqueue_struct *g_ioband_wq; + struct bio_list g_urgent_bios; + int g_io_throttle; + int g_io_limit; + int g_issued[2]; + int g_blocked; + spinlock_t g_lock; + struct mutex g_lock_device; + wait_queue_head_t g_waitq; + wait_queue_head_t g_waitq_suspend; + wait_queue_head_t g_waitq_flush; + + int g_ref; + struct list_head g_list; + int g_flags; + char g_name[IOBAND_NAME_MAX + 1]; + struct policy_type *g_policy; + + /* policy dependent */ + int (*g_can_submit) (struct ioband_group *); + int (*g_prepare_bio) (struct ioband_group *, struct bio *, int); + int (*g_restart_bios) (struct ioband_device *); + void (*g_hold_bio) (struct ioband_group *, struct bio *); + struct bio *(*g_pop_bio) (struct ioband_group *); + int (*g_group_ctr) (struct ioband_group *, char *); + void (*g_group_dtr) (struct ioband_group *); + int (*g_set_param) (struct ioband_group *, char *cmd, char *value); + int (*g_should_block) (struct ioband_group *); + void (*g_show) (struct ioband_group *, int *, char *, unsigned); + + /* members for weight balancing policy */ + int g_epoch; + int g_weight_total; + /* the number of tokens which can be used in every epoch */ + int g_token_bucket; + /* how many epochs tokens can be carried over */ + int g_carryover; + /* how many tokens should be used for one page-sized I/O */ + int g_token_unit; + /* the last group which used a token */ + struct ioband_group *g_current; + /* give another group a chance to be scheduled when the rest + of tokens of the current group reaches this mark */ + int g_yield_mark; + /* the latest group which used up its tokens */ + struct ioband_group *g_expired; + /* the group which has the largest number of tokens in the + active groups */ + struct ioband_group *g_dominant; + /* the number of unused tokens in this epoch */ + int g_token_left; + /* left-over tokens from the previous epoch */ + int g_token_extra; +}; + +struct ioband_group_stat { + unsigned long sectors; + unsigned long immediate; + unsigned long deferred; +}; + +struct ioband_group { + struct list_head c_list; + struct ioband_device *c_banddev; + struct dm_dev *c_dev; + struct dm_target *c_target; + struct bio_list c_blocked_bios; + struct bio_list c_prio_bios; + struct rb_root c_group_root; + struct rb_node c_group_node; + int c_id; /* should be unsigned long or unsigned long long */ + char c_name[IOBAND_NAME_MAX + 1]; /* rfu */ + int c_blocked; + int c_prio_blocked; + wait_queue_head_t c_waitq; + int c_flags; + struct ioband_group_stat c_stat[2]; /* hold rd/wr status */ + struct group_type *c_type; + + /* members for weight balancing policy */ + int c_weight; + int c_my_epoch; + int c_token; + int c_token_initial; + int c_limit; + int c_consumed; + + /* rfu */ + /* struct bio_list c_ordered_tag_bios; */ +}; + +#define IOBAND_URGENT 1 + +#define DEV_BIO_BLOCKED 1 +#define DEV_SUSPENDED 2 + +#define set_device_blocked(dp) ((dp)->g_flags |= DEV_BIO_BLOCKED) +#define clear_device_blocked(dp) ((dp)->g_flags &= ~DEV_BIO_BLOCKED) +#define is_device_blocked(dp) ((dp)->g_flags & DEV_BIO_BLOCKED) + +#define set_device_suspended(dp) ((dp)->g_flags |= DEV_SUSPENDED) +#define clear_device_suspended(dp) ((dp)->g_flags &= ~DEV_SUSPENDED) +#define is_device_suspended(dp) ((dp)->g_flags & DEV_SUSPENDED) + +#define IOG_PRIO_BIO_SYNC 1 +#define IOG_PRIO_QUEUE 2 +#define IOG_BIO_BLOCKED 4 +#define IOG_GOING_DOWN 8 +#define IOG_SUSPENDED 16 +#define IOG_NEED_UP 32 + +#define R_OK 0 +#define R_BLOCK 1 +#define R_YIELD 2 + +#define set_group_blocked(gp) ((gp)->c_flags |= IOG_BIO_BLOCKED) +#define clear_group_blocked(gp) ((gp)->c_flags &= ~IOG_BIO_BLOCKED) +#define is_group_blocked(gp) ((gp)->c_flags & IOG_BIO_BLOCKED) + +#define set_group_down(gp) ((gp)->c_flags |= IOG_GOING_DOWN) +#define clear_group_down(gp) ((gp)->c_flags &= ~IOG_GOING_DOWN) +#define is_group_down(gp) ((gp)->c_flags & IOG_GOING_DOWN) + +#define set_group_suspended(gp) ((gp)->c_flags |= IOG_SUSPENDED) +#define clear_group_suspended(gp) ((gp)->c_flags &= ~IOG_SUSPENDED) +#define is_group_suspended(gp) ((gp)->c_flags & IOG_SUSPENDED) + +#define set_group_need_up(gp) ((gp)->c_flags |= IOG_NEED_UP) +#define clear_group_need_up(gp) ((gp)->c_flags &= ~IOG_NEED_UP) +#define group_need_up(gp) ((gp)->c_flags & IOG_NEED_UP) + +#define set_prio_async(gp) ((gp)->c_flags |= IOG_PRIO_QUEUE) +#define clear_prio_async(gp) ((gp)->c_flags &= ~IOG_PRIO_QUEUE) +#define is_prio_async(gp) \ + ((gp)->c_flags & (IOG_PRIO_QUEUE|IOG_PRIO_BIO_SYNC) == IOG_PRIO_QUEUE) + +#define set_prio_sync(gp) \ + ((gp)->c_flags |= (IOG_PRIO_QUEUE|IOG_PRIO_BIO_SYNC)) +#define clear_prio_sync(gp) \ + ((gp)->c_flags &= ~(IOG_PRIO_QUEUE|IOG_PRIO_BIO_SYNC)) +#define is_prio_sync(gp) \ + ((gp)->c_flags & (IOG_PRIO_QUEUE|IOG_PRIO_BIO_SYNC) == \ + (IOG_PRIO_QUEUE|IOG_PRIO_BIO_SYNC)) + +#define set_prio_queue(gp, sync) \ + ((gp)->c_flags |= (IOG_PRIO_QUEUE|sync)) +#define clear_prio_queue(gp) clear_prio_sync(gp) +#define is_prio_queue(gp) ((gp)->c_flags & IOG_PRIO_QUEUE) +#define prio_queue_sync(gp) ((gp)->c_flags & IOG_PRIO_BIO_SYNC) + +struct policy_type { + const char *p_name; + int (*p_policy_init) (struct ioband_device *, int, char **); +}; + +extern struct policy_type dm_ioband_policy_type[]; + +struct group_type { + const char *t_name; + int (*t_getid) (struct bio *); +}; + +extern struct group_type dm_ioband_group_type[]; _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
