Revert submission 3212512
Reason for revert: Droidmonitor created revert due to b/372273614. Will be verifying through ABTD before submission.
Reverted changes: /q/submissionid:3212512
Change-Id: I37568516e973cb940f1229d52f94b8dc801da2ab
Revert submission 3212512
Reason for revert: Droidmonitor created revert due to b/372273614. Will be verifying through ABTD before submission.
Reverted changes: /q/submissionid:3212512
Change-Id: I3dadc0b7bccfe28bb067a93df2acf2c3ea0f9920
The cgroup.rc file was introduced in 192aee782 ("libprocessgroup: Add
support for task profiles") back with the initial support for task
profiles. It was intended to optimize performance associated with cgroup
operations. However over time, supporting this file led to making
libprocessgroup code more complicated (such as the cgrouprc LLNDK
interface), and the file ended up getting mmaped into nearly every
process on Android even though only a handful of them actually use it.
Replacing this file with reading and parsing of cgroup information on
demand allows us to simplify and shrink libprocessgroup, and eliminates
thousands of unused mappings without negatively affecting boot time or
other performance metrics.
Bug: 349105928
Test: Verified with memcg v2 and MaxActivationDepth 1 on Cuttlefish, Raven, and Mokey
Change-Id: Ic3f01fdf7fda89a56ab80657e1cf4573156273e6
To avoid duplicate symbol linker error and prep for addition of json
descriptor reading and activation functions in upcoming changes.
Bug: 349105928
Test: m
Change-Id: I5cd663d6007ef330b872b8cf8ed046ee68b6d736
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
