diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/cgroups/blkio-controller.txt | 24 | ||||
| -rw-r--r-- | Documentation/cgroups/unified-hierarchy.txt | 61 |
2 files changed, 63 insertions, 22 deletions
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index 68b6a6a470b0..12686bec37b9 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt @@ -201,7 +201,7 @@ Proportional weight policy files specifies the number of bytes. - blkio.io_serviced - - Number of IOs completed to/from the disk by the group. These + - Number of IOs (bio) issued to the disk by the group. These are further divided by the type of operation - read or write, sync or async. First two fields specify the major and minor number of the device, third field specifies the operation type and the fourth field @@ -327,18 +327,11 @@ Note: If both BW and IOPS rules are specified for a device, then IO is subjected to both the constraints. - blkio.throttle.io_serviced - - Number of IOs (bio) completed to/from the disk by the group (as - seen by throttling policy). These are further divided by the type - of operation - read or write, sync or async. First two fields specify - the major and minor number of the device, third field specifies the - operation type and the fourth field specifies the number of IOs. - - blkio.io_serviced does accounting as seen by CFQ and counts are in - number of requests (struct request). On the other hand, - blkio.throttle.io_serviced counts number of IO in terms of number - of bios as seen by throttling policy. These bios can later be - merged by elevator and total number of requests completed can be - lesser. + - Number of IOs (bio) issued to the disk by the group. These + are further divided by the type of operation - read or write, sync + or async. First two fields specify the major and minor number of the + device, third field specifies the operation type and the fourth field + specifies the number of IOs. - blkio.throttle.io_service_bytes - Number of bytes transferred to/from the disk by the group. These @@ -347,11 +340,6 @@ Note: If both BW and IOPS rules are specified for a device, then IO is device, third field specifies the operation type and the fourth field specifies the number of bytes. - These numbers should roughly be same as blkio.io_service_bytes as - updated by CFQ. The difference between two is that - blkio.io_service_bytes will not be updated if CFQ is not operating - on request queue. - Common files among various policies ----------------------------------- - blkio.reset_stats diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index 1ee9caf29e57..e0975c2cf03d 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -27,7 +27,7 @@ CONTENTS 5-3-1. Format 5-3-2. Control Knobs 5-4. Per-Controller Changes - 5-4-1. blkio + 5-4-1. io 5-4-2. cpuset 5-4-3. memory 6. Planned Changes @@ -203,7 +203,7 @@ other issues. The mapping from nice level to weight isn't obvious or universal, and there are various other knobs which simply aren't available for tasks. -The blkio controller implicitly creates a hidden leaf node for each +The io controller implicitly creates a hidden leaf node for each cgroup to host the tasks. The hidden leaf has its own copies of all the knobs with "leaf_" prefixed. While this allows equivalent control over internal tasks, it's with serious drawbacks. It always adds an @@ -438,9 +438,62 @@ may be specified in any order and not all pairs have to be specified. 5-4. Per-Controller Changes -5-4-1. blkio +5-4-1. io -- blk-throttle becomes properly hierarchical. +- blkio is renamed to io. The interface is overhauled anyway. The + new name is more in line with the other two major controllers, cpu + and memory, and better suited given that it may be used for cgroup + writeback without involving block layer. + +- Everything including stat is always hierarchical making separate + recursive stat files pointless and, as no internal node can have + tasks, leaf weights are meaningless. The operation model is + simplified and the interface is overhauled accordingly. + + io.stat + + The stat file. The reported stats are from the point where + bio's are issued to request_queue. The stats are counted + independent of which policies are enabled. Each line in the + file follows the following format. More fields may later be + added at the end. + + $MAJ:$MIN rbytes=$RBYTES wbytes=$WBYTES rios=$RIOS wrios=$WIOS + + io.weight + + The weight setting, currently only available and effective if + cfq-iosched is in use for the target device. The weight is + between 1 and 10000 and defaults to 100. The first line + always contains the default weight in the following format to + use when per-device setting is missing. + + default $WEIGHT + + Subsequent lines list per-device weights of the following + format. + + $MAJ:$MIN $WEIGHT + + Writing "$WEIGHT" or "default $WEIGHT" changes the default + setting. Writing "$MAJ:$MIN $WEIGHT" sets per-device weight + while "$MAJ:$MIN default" clears it. + + This file is available only on non-root cgroups. + + io.max + + The maximum bandwidth and/or iops setting, only available if + blk-throttle is enabled. The file is of the following format. + + $MAJ:$MIN rbps=$RBPS wbps=$WBPS riops=$RIOPS wiops=$WIOPS + + ${R|W}BPS are read/write bytes per second and ${R|W}IOPS are + read/write IOs per second. "max" indicates no limit. Writing + to the file follows the same format but the individual + settings may be ommitted or specified in any order. + + This file is available only on non-root cgroups. 5-4-2. cpuset |