diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/cgroups/cgroups.txt | 14 | ||||
| -rw-r--r-- | Documentation/cgroups/unified-hierarchy.txt | 35 |
2 files changed, 43 insertions, 6 deletions
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index 821de56d1580..10c949b293e4 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -599,6 +599,20 @@ fork. If this method returns 0 (success) then this should remain valid while the caller holds cgroup_mutex and it is ensured that either attach() or cancel_attach() will be called in future. +void css_reset(struct cgroup_subsys_state *css) +(cgroup_mutex held by caller) + +An optional operation which should restore @css's configuration to the +initial state. This is currently only used on the unified hierarchy +when a subsystem is disabled on a cgroup through +"cgroup.subtree_control" but should remain enabled because other +subsystems depend on it. cgroup core makes such a css invisible by +removing the associated interface files and invokes this callback so +that the hidden subsystem can return to the initial neutral state. +This prevents unexpected resource control from a hidden css and +ensures that the configuration is in the initial state when it is made +visible again later. + void cancel_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) (cgroup_mutex held by caller) diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index 324b182e6000..4f4563277864 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -94,12 +94,35 @@ change soon. mount -t cgroup -o __DEVEL__sane_behavior cgroup $MOUNT_POINT -All controllers which are not bound to other hierarchies are -automatically bound to unified hierarchy and show up at the root of -it. Controllers which are enabled only in the root of unified -hierarchy can be bound to other hierarchies at any time. This allows -mixing unified hierarchy with the traditional multiple hierarchies in -a fully backward compatible way. +All controllers which support the unified hierarchy and are not bound +to other hierarchies are automatically bound to unified hierarchy and +show up at the root of it. Controllers which are enabled only in the +root of unified hierarchy can be bound to other hierarchies. This +allows mixing unified hierarchy with the traditional multiple +hierarchies in a fully backward compatible way. + +For development purposes, the following boot parameter makes all +controllers to appear on the unified hierarchy whether supported or +not. + + cgroup__DEVEL__legacy_files_on_dfl + +A controller can be moved across hierarchies only after the controller +is no longer referenced in its current hierarchy. Because per-cgroup +controller states are destroyed asynchronously and controllers may +have lingering references, a controller may not show up immediately on +the unified hierarchy after the final umount of the previous +hierarchy. Similarly, a controller should be fully disabled to be +moved out of the unified hierarchy and it may take some time for the +disabled controller to become available for other hierarchies; +furthermore, due to dependencies among controllers, other controllers +may need to be disabled too. + +While useful for development and manual configurations, dynamically +moving controllers between the unified and other hierarchies is +strongly discouraged for production use. It is recommended to decide +the hierarchies and controller associations before starting using the +controllers. 2-2. cgroup.subtree_control |