On 2024/9/10 3:01, Michal Koutný wrote:
On Thu, Sep 05, 2024 at 01:41:28PM GMT, Chen Ridong <chenridong@xxxxxxxxxx> wrote:
Whether a cgroup is frozen is determined solely by whether it is set to
to be frozen and whether its parent is frozen. Currently, when is cgroup
is frozen or unfrozen, it iterates through the entire subtree to freeze
or unfreeze its descentdants.
It's more to maintain the numeric freeze "layers".
However, this is unesessary for a cgroup that does not change its
effective frozen status.
True.
+static inline void cgroup_update_efreeze(struct cgroup *cgrp)
+{
+ struct cgroup *parent = cgroup_parent(cgrp);
+ bool p_e = false;
+
+ if (parent)
+ p_e = parent->freezer.e_freeze;
+
+ cgrp->freezer.e_freeze = cgrp->freezer.freeze | p_e;
Better be || on bools
Thanks you, that is right.
I'd open code this inside the loop of cgroup_freeze since it is not
context-less function and it relies on top-down processing.
Root cgrp cannot be frozen. You can bail out early in the beginning of
cgroup_freeze() (possibly with a WARN_ON) and then assume parent is
always valid when iterating.
'cgroup.freeze' is with CFTYPE_NOT_ON_ROOT tag, root cgroup will never
be frozen, considering root cgroup seems to be unesessary. I will open
the code inside the loop of cgroup_freeze in next patch.
Thanks
Ridong
I think maintaining the e_freeze in this "saturated arithmetic" form is
a sensible change.
Thanks,
Michal
