cgroup_fork(9)

💖 cgroup_fork(9) 💖

okay so you found yourself a page from the Kernel API Manual (section 9, kernel-space girlies only ✨) and it's about cgroup_fork — the little function that does the cgroup setup when a brand new task gets copied into existence. it's short, it's sweet, it's giving "one job and she does it" 🎀

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🌸 NAME 🌸

cgroup_fork — literally just initializes the cgroup related fields during copy_process(). that's it. that's the whole assignment 💅

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✨ SYNOPSIS ✨

void cgroup_fork (struct task_struct *child );

no return value, no drama, no cap 🫶

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🦋 ARGUMENTS 🦋

• child — pointer to the task_struct of the forking parent process. yes bestie, that's exactly what the original says, don't come for me 😭 that's the pointer you hand over.

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💜 DESCRIPTION 💜

so here's the lore 🔥 a task is associated with init_css_set until cgroup_post_fork comes along and attaches it to the target css_set. that's the vibe check: you start out in init_css_set, you get moved later, cgroup_post_fork is the one who does the moving. periodt 💫

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👑 SEE ALSO 👑

Kernel file ./kernel/cgroup/cgroup.c — that's where the whole friend group lives 🧚

and the whole squad, in order, no one left out, i would never 🙈:

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_vet_dst(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_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)

like i said. the whole squad. iykyk 💀

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that's the whole page bestie, go read the source and slay 🫶 the source being ./kernel/cgroup, dated October 2026, and the manual being the Kernel API Manual — mwah, stan a kernel doc, bye 💖✨