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Diffstat (limited to 'Documentation/admin-guide/cgroup-v2.rst')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index b1e81aa8598a..babbe04c8d37 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -56,6 +56,7 @@ v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst <cgrou 5-3-3. IO Latency 5-3-3-1. How IO Latency Throttling Works 5-3-3-2. IO Latency Interface Files + 5-3-4. IO Priority 5-4. PID 5-4-1. PID Interface Files 5-5. Cpuset @@ -952,6 +953,21 @@ All cgroup core files are prefixed with "cgroup." it's possible to delete a frozen (and empty) cgroup, as well as create new sub-cgroups. + cgroup.kill + A write-only single value file which exists in non-root cgroups. + The only allowed value is "1". + + Writing "1" to the file causes the cgroup and all descendant cgroups to + be killed. This means that all processes located in the affected cgroup + tree will be killed via SIGKILL. + + Killing a cgroup tree will deal with concurrent forks appropriately and + is protected against migrations. + + In a threaded cgroup, writing this file fails with EOPNOTSUPP as + killing cgroups is a process directed operation, i.e. it affects + the whole thread-group. + Controllers =========== @@ -1866,6 +1882,60 @@ IO Latency Interface Files duration of time between evaluation events. Windows only elapse with IO activity. Idle periods extend the most recent window. +IO Priority +~~~~~~~~~~~ + +A single attribute controls the behavior of the I/O priority cgroup policy, +namely the blkio.prio.class attribute. The following values are accepted for +that attribute: + + no-change + Do not modify the I/O priority class. + + none-to-rt + For requests that do not have an I/O priority class (NONE), + change the I/O priority class into RT. Do not modify + the I/O priority class of other requests. + + restrict-to-be + For requests that do not have an I/O priority class or that have I/O + priority class RT, change it into BE. Do not modify the I/O priority + class of requests that have priority class IDLE. + + idle + Change the I/O priority class of all requests into IDLE, the lowest + I/O priority class. + +The following numerical values are associated with the I/O priority policies: + ++-------------+---+ +| no-change | 0 | ++-------------+---+ +| none-to-rt | 1 | ++-------------+---+ +| rt-to-be | 2 | ++-------------+---+ +| all-to-idle | 3 | ++-------------+---+ + +The numerical value that corresponds to each I/O priority class is as follows: + ++-------------------------------+---+ +| IOPRIO_CLASS_NONE | 0 | ++-------------------------------+---+ +| IOPRIO_CLASS_RT (real-time) | 1 | ++-------------------------------+---+ +| IOPRIO_CLASS_BE (best effort) | 2 | ++-------------------------------+---+ +| IOPRIO_CLASS_IDLE | 3 | ++-------------------------------+---+ + +The algorithm to set the I/O priority class for a request is as follows: + +- Translate the I/O priority class policy into a number. +- Change the request I/O priority class into the maximum of the I/O priority + class policy number and the numerical I/O priority class. + PID --- @@ -1986,6 +2056,17 @@ Cpuset Interface Files The value of "cpuset.mems" stays constant until the next update and won't be affected by any memory nodes hotplug events. + Setting a non-empty value to "cpuset.mems" causes memory of + tasks within the cgroup to be migrated to the designated nodes if + they are currently using memory outside of the designated nodes. + + There is a cost for this memory migration. The migration + may not be complete and some memory pages may be left behind. + So it is recommended that "cpuset.mems" should be set properly + before spawning new tasks into the cpuset. Even if there is + a need to change "cpuset.mems" with active tasks, it shouldn't + be done frequently. + cpuset.mems.effective A read-only multiple values file which exists on all cpuset-enabled cgroups. |