cgroup_migrate_vet_dst(9)

✨ cgroup_migrate_vet_dst ✨

okay bestie, welcome to the Kernel API Manual, section 9 — this is the cgroup_migrate_vet_dst(9) page, and it's lowkey a vibe check for cgroups 💅.

🌸 NAME 🌸

cgroup_migrate_vet_dst — verify whether a cgroup can be migration destination.

🦋 SYNOPSIS 🦋

int cgroup_migrate_vet_dst (struct cgroup *dst_cgrp );

🎀 ARGUMENTS 🎀

• dst_cgrp — the destination cgroup to test. that's the one getting the vibe check 🫶

💜 DESCRIPTION 💜

here's the tea: on the default hierarchy, subtree_control must be zero for migration destination cgroups with tasks — the exceptions are the mixable, (possible) thread root, and threaded cgroups. why? so child cgroups don't compete against tasks. periodt ✨

🔥 SEE ALSO 🔥

The relevant kernel file is ./kernel/cgroup/cgroup.c, and these are the linked besties — all with their (9):

• cgroup_ssid_enabled(9), cgroup_on_dfl(9), cgroup_e_css_by_mask(9), cgroup_e_css(9), cgroup_get_e_css(9), __cgroup_task_count(9), cgroup_task_count(9)
• for_each_css(9), do_each_subsys_mask(9), css_set_populated(9), css_update_populated(9), css_set_update_populated(9), css_set_move_task(9), compare_css_sets(9), find_existing_css_set(9)
• allocate_cgrp_cset_links(9), link_css_set(9), find_css_set(9), cgroup_file_mode(9), cgroup_calc_subtree_ss_mask(9), cgroup_kn_unlock(9), cgroup_kn_lock_live(9), css_clear_dir(9)
• css_populate_dir(9), cgroup_attach_lock(9), cgroup_attach_unlock(9), cgroup_migrate_add_task(9), cgroup_taskset_first(9), cgroup_taskset_next(9), cgroup_migrate_execute(9), cgroup_migrate_finish(9)
• cgroup_migrate_add_src(9), cgroup_migrate_prepare_dst(9), cgroup_migrate(9), cgroup_attach_task(9), cgroup_update_dfl_csses(9), cgroup_lock_and_drain_offline(9), cgroup_save_control(9)
• cgroup_propagate_control(9), cgroup_restore_control(9), cgroup_apply_control_enable(9), cgroup_apply_control_disable(9), cgroup_apply_control(9), cgroup_finalize_control(9), cgroup_enable_threaded(9)
• cgroup_tryget_css(9), cgroup_addrm_files(9), cgroup_rm_cftypes(9), cgroup_add_cftypes(9), cgroup_add_dfl_cftypes(9), cgroup_add_legacy_cftypes(9), cgroup_file_notify(9)
• cgroup_file_show(9), css_next_child(9), css_next_descendant_pre(9), css_rightmost_descendant(9), css_next_descendant_post(9), css_has_online_children(9), css_task_iter_advance_css_set(9)
• css_task_iter_start(9), css_task_iter_next(9), css_task_iter_end(9), css_create(9), kill_css_sync(9), kill_css_finish(9), cgroup_destroy_locked(9)
• cgroup_init_early(9), cgroup_init(9), cgroup_fork(9), cgroup_v1v2_get_from_file(9), cgroup_get_from_file(9), cgroup_css_set_fork(9), cgroup_css_set_put_fork(9)
• cgroup_can_fork(9), cgroup_cancel_fork(9), cgroup_post_fork(9), cgroup_task_exit(9), css_tryget_online_from_dir(9), css_from_id(9), cgroup_get_from_path(9)
• cgroup_v1v2_get_from_fd(9), cgroup_get_from_fd(9), cgroup_parse_float(9)

xoxo, your girl 💖 — this was cgroup_migrate_vet_dst(9) from ./kernel/cgroup, dated October 2026. go forth and vet those destinations, bestie 🧚‍♀️