28b37f2704
Cgroup v2 controllers can be enabled in a subtree of the shared hierarchy. That allows users to limit the number of cgroups with a controller enabled to less than the total number of cgroups. [1] There are costs for each cgroup. Kernel memory is used for each cgroup, plus additional memory for each active controller in each cgroup. Some kernel operations scale with the number of cgroups (with a given controller enabled), so it can be desirable to minimize the number of cgroups with that controller enabled. This change allows each v2 controller configuration to specify a maximum activation depth, past which the controller will not be activated deeper in the Android cgroup v2 hierarchy. The hierarchy root is defined as depth 0. MaxActivationDepth is the field name for this purpose for controllers in the Controllers array under Cgroups2 in cgroups.json. Here are two examples: "MaxActivationDepth": 1 This will activate the controller in every per-application cgroup, but not in the per-process cgroups below. /sys/fs/cgroup depth=0 active=true (controller listed in cgroup.subtree_control) /sys/fs/cgroup/uid_0 depth=1 active=true (controller NOT listed in cgroup.subtree_control) /sys/fs/cgroup/uid_0/pid_100 depth=2 active=false (controller NOT listed in cgroup.subtree_control) This can also be used with PRODUCT_CGROUP_V2_SYS_APP_ISOLATION_ENABLED := true. "MaxActivationDepth": 1 This will activate the controller only at the app / system level, but not in per-application cgroups below. This results in a total of only 3 cgroups with the controller enabled (root, apps, system). /sys/fs/cgroup depth=0 active=true (controller listed in cgroup.subtree_control) /sys/fs/cgroup/apps depth=1 active=true (controller NOT listed in cgroup.subtree_control) /sys/fs/cgroup/apps/uid_10000 depth=2 active=false (controller NOT listed in cgroup.subtree_control) /sys/fs/cgroup/apps/uid_10000/pid_100 depth=3 active=false (controller NOT listed in cgroup.subtree_control) [1] https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html#enabling-and-disabling Bug: 346584259 Test: Cuttlefish with memcg v2 Change-Id: I62109ea935261c51fc30b2054c4d28d0360f7985 |
||
|---|---|---|
| .. | ||
| Android.bp | ||
| cgroups.json | ||
| cgroups.proto | ||
| cgroups.recovery.json | ||
| cgroups_28.json | ||
| cgroups_29.json | ||
| cgroups_30.json | ||
| cgroups_test.h | ||
| task_profiles.json | ||
| task_profiles.proto | ||
| task_profiles_28.json | ||
| task_profiles_29.json | ||
| task_profiles_30.json | ||
| task_profiles_test.h | ||
| test.cpp | ||
| test_vendor.cpp | ||