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authorLinus Torvalds <torvalds@linux-foundation.org>2021-07-01 17:22:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-01 17:22:14 -0700
commit3dbdb38e286903ec220aaf1fb29a8d94297da246 (patch)
treef80cd38836298d6bb465462e30f4dd644b018735 /Documentation
parente267992f9ef0bf717d70a9ee18049782f77e4b3a (diff)
parent3958e2d0c34e18c41b60dc01832bd670a59ef70f (diff)
Merge branch 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: - cgroup.kill is added which implements atomic killing of the whole subtree. Down the line, this should be able to replace the multiple userland implementations of "keep killing till empty". - PSI can now be turned off at boot time to avoid overhead for configurations which don't care about PSI. * 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: make per-cgroup pressure stall tracking configurable cgroup: Fix kernel-doc cgroup: inline cgroup_task_freeze() tests/cgroup: test cgroup.kill tests/cgroup: move cg_wait_for(), cg_prepare_for_wait() tests/cgroup: use cgroup.kill in cg_killall() docs/cgroup: add entry for cgroup.kill cgroup: introduce cgroup.kill
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst15
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt9
2 files changed, 22 insertions, 2 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 4e59925e6583..5c7377b5bd3e 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -953,6 +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
===========
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2991f6e692bd..0315407f5f57 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -497,16 +497,21 @@
ccw_timeout_log [S390]
See Documentation/s390/common_io.rst for details.
- cgroup_disable= [KNL] Disable a particular controller
- Format: {name of the controller(s) to disable}
+ cgroup_disable= [KNL] Disable a particular controller or optional feature
+ Format: {name of the controller(s) or feature(s) to disable}
The effects of cgroup_disable=foo are:
- foo isn't auto-mounted if you mount all cgroups in
a single hierarchy
- foo isn't visible as an individually mountable
subsystem
+ - if foo is an optional feature then the feature is
+ disabled and corresponding cgroup files are not
+ created
{Currently only "memory" controller deal with this and
cut the overhead, others just disable the usage. So
only cgroup_disable=memory is actually worthy}
+ Specifying "pressure" disables per-cgroup pressure
+ stall information accounting feature
cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1
Format: { { controller | "all" | "named" }