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cgroup: Minor reorganization of cgroup_create()

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cgroup_bpf init and exit handling will be moved to a notifier chain. In
prepartion, reorganize cgroup_create() a bit so that the new cgroup is fully
initialized before any outside changes are made.

- cgrp->ancestors[] initialization and the hierarchical nr_descendants and
  nr_frozen_descendants updates were in the same loop. Separate them out and
  do the former earlier and do the latter later.

- Relocate cgroup_bpf_inherit() call so that it's after all cgroup
  initializations are complete.

No visible behavior changes expected.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo
2025-05-22 09:19:57 -10:00
parent d16e7994c8
commit cd22cbad1b
1 changed files with 24 additions and 24 deletions
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kernel/cgroup/cgroup.c
+24 -24
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@@ -5660,7 +5660,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
struct cgroup_root *root = parent->root;
struct cgroup *cgrp, *tcgrp;
struct kernfs_node *kn;
int level = parent->level + 1;
int i, level = parent->level + 1;
int ret;
/* allocate the cgroup and its ID, 0 is reserved for the root */
@@ -5700,11 +5700,8 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
if (ret)
goto out_stat_exit;
if (cgrp->root == &cgrp_dfl_root) {
ret = cgroup_bpf_inherit(cgrp);
if (ret)
goto out_psi_free;
}
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp))
cgrp->ancestors[tcgrp->level] = tcgrp;
/*
* New cgroup inherits effective freeze counter, and
@@ -5722,24 +5719,6 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
set_bit(CGRP_FROZEN, &cgrp->flags);
}
spin_lock_irq(&css_set_lock);
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
cgrp->ancestors[tcgrp->level] = tcgrp;
if (tcgrp != cgrp) {
tcgrp->nr_descendants++;
/*
* If the new cgroup is frozen, all ancestor cgroups
* get a new frozen descendant, but their state can't
* change because of this.
*/
if (cgrp->freezer.e_freeze)
tcgrp->freezer.nr_frozen_descendants++;
}
}
spin_unlock_irq(&css_set_lock);
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
@@ -5748,7 +5727,28 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
cgrp->self.serial_nr = css_serial_nr_next++;
if (cgrp->root == &cgrp_dfl_root) {
ret = cgroup_bpf_inherit(cgrp);
if (ret)
goto out_psi_free;
}
/* allocation complete, commit to creation */
spin_lock_irq(&css_set_lock);
for (i = 0; i < level; i++) {
tcgrp = cgrp->ancestors[i];
tcgrp->nr_descendants++;
/*
* If the new cgroup is frozen, all ancestor cgroups get a new
* frozen descendant, but their state can't change because of
* this.
*/
if (cgrp->freezer.e_freeze)
tcgrp->freezer.nr_frozen_descendants++;
}
spin_unlock_irq(&css_set_lock);
list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
atomic_inc(&root->nr_cgrps);
cgroup_get_live(parent);