cgroup_file_notify(9)

💅 cgroup_file_notify(9)

okay so this is page 9 of the Kernel API Manual, and bestie, it's a short one — but it's a mood, and it's lowkey important, so let's get into it 🫶

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🌸 NAME 🌸

cgroup_file_notify — the girl whose whole job is to generate a file modified event for a cgroup_file ✨ like, she's literally a notification factory and nothing else, and honestly? iconic.

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🦋 SYNOPSIS 🦋

void cgroup_file_notify (struct cgroup_file *cfile );

she takes one arg, she returns void (so, nothing, no takebacks, no receipts 💀) 🎀

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🎀 ARGUMENTS 🎀

• cfile — the target cgroup_file. that's it. that's the whole arg. no cap 🍓

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💅 DESCRIPTION 💅

so here's the vibe check: cfile must have been obtained by setting cftype->file_offset. not "should", not "ideally", not "if ur feeling cute" — must. that's the only legit way in, iykyk 🙈 if ur cgroup_file didn't come from cftype->file_offset, this is not ur moment.

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👑 SEE ALSO 👑

no bc this list is a whole squad and they all showed up — plus the kernel file itself lives at ./kernel/cgroup/cgroup.c, so say hi to the source bestie 💖

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_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)

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and that's the page!! short, sweet, aggressively specific about one single precondition. slay. periodt. 🔥

ngl the whole thing comes from the kernel source at ./kernel/cgroup, and this particular page is dated October 2026 — so yeah, timestamped, archived, and still serving main character energy 💜✨🧚‍♀️