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| author |   Tejun Heo <tj@kernel.org> | 2022-07-29 13:10:16 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2022-08-15 11:16:47 -1000 |
| commit | 7f203bc89eb66d6afde7eae91347fc0352090cc3 (patch) | |
| tree | a8a4f1fa1203a0200089982587709f334b0ff968 /include/linux/cgroup.h | |
| parent | Linux 6.0-rc1 (diff) | |
| download | linux-dev-7f203bc89eb66d6afde7eae91347fc0352090cc3.tar.xz linux-dev-7f203bc89eb66d6afde7eae91347fc0352090cc3.zip | |
cgroup: Replace cgroup->ancestor_ids[] with ->ancestors[]
Every cgroup knows all its ancestors through its ->ancestor_ids[]. There's
no advantage to remembering the IDs instead of the pointers directly and
this makes the array useless for finding an actual ancestor cgroup forcing
cgroup_ancestor() to iteratively walk up the hierarchy instead. Let's
replace cgroup->ancestor_ids[] with ->ancestors[] and remove the walking-up
from cgroup_ancestor().
While at it, improve comments around cgroup_root->cgrp_ancestor_storage.
This patch shouldn't cause user-visible behavior differences.
v2: Update cgroup_ancestor() to use ->ancestors[].
v3: cgroup_root->cgrp_ancestor_storage's type is updated to match
cgroup->ancestors[]. Better comments.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index ed53bfe7c46c..4d143729b246 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -574,7 +574,7 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp, { if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) return false; - return cgrp->ancestor_ids[ancestor->level] == cgroup_id(ancestor); + return cgrp->ancestors[ancestor->level] == ancestor; } /** @@ -591,11 +591,9 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp, static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp, int ancestor_level) { - if (cgrp->level < ancestor_level) + if (ancestor_level < 0 || ancestor_level > cgrp->level) return NULL; - while (cgrp && cgrp->level > ancestor_level) - cgrp = cgroup_parent(cgrp); - return cgrp; + return cgrp->ancestors[ancestor_level]; } /** |