cgroup_common_ancestor(9)

🎀 NAME 🎀

okay so bestie, this is cgroup_common_ancestor from the Kernel API Manual — yes, the section 9 one, iykyk — and its whole job is literally find common ancestor of two cgroups. That's the name-card. Periodt. 💅

🌸 SYNOPSIS 🌸

struct cgroup * cgroup_common_ancestor (struct cgroup *a , struct cgroup
*b );

🦋 ARGUMENTS 🦋

• a — first cgroup to find common ancestor of. Like, one side of the family tree you're checking, bestie 🌳
• b — second cgroup to find common ancestor of. The other side, matching energy required 💖

✨ DESCRIPTION ✨

okay so the actual vibe: find the first cgroup that is an ancestor of both a and b, if it exists, and return a pointer to it. If such a cgroup doesn't exist, return NULL. That's it. No cap. 🔥

Safety check, because we stay safe: this function is safe to call as long as both a and b are accessible. 🫶

👑 SEE ALSO 👑

go peek at the Kernel file ./include/linux/cgroup.h and these iconic cross-refs, bestie:

• cgroup_subsys_enabled(9)
• cgroup_subsys_on_dfl(9)
• css_for_each_child(9)
• css_for_each_descendant_pre(9)
• css_for_each_descendant_post(9)
• cgroup_taskset_for_each(9)
• cgroup_taskset_for_each_leader(9)
• cgroup_css(9)
• css_is_dying(9)
• task_css_set_check(9)
• task_css_check(9)
• task_css_set(9)
• task_css(9)
• task_get_css(9)
• task_css_is_root(9)
• cgroup_is_descendant(9)
• cgroup_ancestor(9)
• task_under_cgroup_hierarchy(9)

source vibes: ./include/linux · date: October 2026 · page: cgroup_common_ancestor(9) — mwah bestie, go be amazing 💖🎀