Commit Graph

65 Commits

Author SHA1 Message Date
Pavel Hrdina
4fe4847438 vircgroup: introduce virCgroupV2Remove
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
89f52abd07 vircgroup: introduce virCgroupV2MakeGroup
When creating cgroup hierarchy we need to enable controllers in the
parent cgroup in order to be usable.  That means writing "+{controller}"
into cgroup.subtree_control file.  We can enable only controllers that
are enabled for parent cgroup, that means we need to do that for the
whole cgroup tree.

Cgroups for threads needs to be handled differently in cgroup v2.  There
are two types of controllers:

    - domain controllers: these cannot be enabled for threads
    - threaded controllers: these can be enabled for threads

In addition there are multiple types of cgroups:

    - domain: normal cgroup
    - domain threaded: a domain cgroup that serves as root for threaded
                       cgroups
    - domain invalid: invalid cgroup, can be changed into threaded, this
                      is the default state if you create subgroup inside
                      domain threaded group or threaded group
    - threaded: threaded cgroup which can have domain threaded or
                threaded as parent group

In order to create threaded cgroup it's sufficient to write "threaded"
into cgroup.type file, it will automatically make parent cgroup
"domain threaded" if it was only "domain".  In case the parent cgroup
is already "domain threaded" or "threaded" it will modify only the type
of current cgroup.  After that we can enable threaded controllers.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
0542640a9c vircgroup: introduce virCgroupV2PathOfController
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
171c700cd8 vircgroup: introduce virCgroupV2GetAnyController
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
c8f08a5346 vircgroup: introduce virCgroupV2HasController
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
e1bb7fffe2 vircgroup: introduce virCgroupV2DetectControllers
Cgroup v2 has only single mount point for all controllers.  The list
of controllers is stored in cgroup.controllers file, name of controllers
are separated by space.

In cgroup v2 there is no cpuacct controller, the cpu.stat file always
exists with usage stats.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
f7394dcf01 vircgroup: introduce virCgroupV2StealPlacement
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
9aa8226d86 vircgroup: introduce virCgroupV2ValidatePlacement
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
1efcf202e7 vircgroup: introduce virCgroupV2DetectPlacement
If the placement was copied from parent or set to absolute path
there is nothing to do, otherwise set the placement based on
process placement from /proc/self/cgroup or /proc/{pid}/cgroup.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
50f61a46fc vircgroup: introduce virCgroupV2DetectMounts
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
7a86201dd6 vircgroup: introduce virCgroupV2CopyPlacement
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
38a3fb5647 vircgroup: introduce virCgroupV2CopyMounts
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
3a365ef697 vircgroup: introduce virCgroupV2ValidateMachineGroup
When reconnecting to a domain we are validating the cgroup name.
In case of cgroup v2 we need to validate only the new format for host
without systemd '{machinename}.libvirt-{drivername}' or scope name
generated by systemd.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
034ef217d7 vircgroup: introduce virCgroupV2Available
We cannot detect only mount points to figure out whether cgroup v2
is available because systemd uses cgroup v2 for process tracking and
all controllers are mounted as cgroup v1 controllers.

To make sure that this is no the situation we need to check
'cgroup.controllers' file if it's not empty to make sure that cgroup
v2 is not mounted only for process tracking.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00
Pavel Hrdina
b4ddf5ae62 util: introduce cgroup v2 files
Place cgroup v2 backend type before cgroup v1 to make it obvious
that cgroup v2 is preferred implementation.

Following patches will introduce support for hybrid configuration
which will allow us to use both at the same time, but we should
prefer cgroup v2 regardless.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2018-10-05 15:53:29 +02:00