mod_delayed_work_on(9)

mod_delayed_work_on(9) — okay so this is from the Kernel API Manual, and she is the function you call when a delayed work needs a little schedule glow-up on a specific CPU. bestie, let’s get into it. 🎀

✨ NAME ✨

mod_delayed_work_on — modify delay of or queue a delayed work on specific CPU. 💅

✨ SYNOPSIS ✨

bool mod_delayed_work_on (int cpu , struct workqueue_struct *wq , struct delayed_work *dwork , unsigned long delay );

✨ ARGUMENTS ✨

• cpu — CPU number to execute work on. 🖥️
• wq — workqueue to use. 🎀
• dwork — work to queue. 🦋
• delay — number of jiffies to wait before queueing. ⏳

✨ DESCRIPTION ✨

okay so here’s the tea: if dwork is idle, this is equivalent to queue_delayed_work_on. otherwise, you’re modifying dwork’s timer so that it expires after delay. 🕰️✨

and if delay is zero, work is guaranteed to be scheduled immediately regardless of its current state. that’s the icon behavior, no cap. 💅

this function is safe to call from any context, including IRQ handler. not me being brave. see try_to_grab_pending for details. 🫶

✨ RETURN ✨

• false — dwork was idle and queued. 😴➡️📋
• true — dwork was pending and its timer was modified. ⏲️✨

✨ SEE ALSO ✨

• Kernel file ./kernel/workqueue.c — and then the whole squad: for_each_pool(9), for_each_pool_worker(9), for_each_pwq(9), worker_pool_assign_id(9), unbound_effective_cpumask(9), get_work_pool(9), worker_set_flags(9), worker_clr_flags(9), worker_enter_idle(9), worker_leave_idle(9), find_worker_executing_work(9), move_linked_works(9), assign_work(9).
• kick_pool_pick(9), kick_pool(9), wq_worker_running(9), wq_worker_sleeping(9), wq_worker_tick(9), wq_worker_last_func(9), wq_node_nr_active(9), wq_update_node_max_active(9), get_pwq(9), put_pwq(9), put_pwq_unlocked(9), pwq_tryinc_nr_active(9), pwq_activate_first_inactive(9), unplug_oldest_pwq(9).
• node_activate_pending_pwq(9), pwq_dec_nr_active(9), pwq_dec_nr_in_flight(9), try_to_grab_pending(9), work_grab_pending(9), insert_work(9), queue_work_on(9), select_numa_node_cpu(9), queue_work_node(9), queue_delayed_work_on(9), queue_rcu_work(9), worker_attach_to_pool(9), worker_detach_from_pool(9), create_worker(9).
• set_worker_dying(9), idle_worker_timeout(9), idle_cull_fn(9), maybe_create_worker(9), manage_workers(9), process_one_work(9), process_scheduled_works(9), worker_thread(9), rescuer_thread(9), check_flush_dependency(9), insert_wq_barrier(9), flush_workqueue_prep_pwqs(9), __flush_workqueue(9), drain_workqueue(9).
• flush_work(9), flush_delayed_work(9), flush_rcu_work(9), cancel_work_sync(9), cancel_delayed_work(9), cancel_delayed_work_sync(9), disable_work(9), disable_work_sync(9), enable_work(9), disable_delayed_work(9), disable_delayed_work_sync(9), enable_delayed_work(9), schedule_on_each_cpu(9).
• execute_in_process_context(9), free_workqueue_attrs(9), alloc_workqueue_attrs(9), init_worker_pool(9), put_unbound_pool(9), get_unbound_pool(9), wq_calc_pod_cpumask(9), apply_workqueue_attrs(9), unbound_wq_update_pwq(9), wq_adjust_max_active(9), destroy_workqueue(9), workqueue_set_max_active(9), workqueue_set_min_active(9).
• current_work(9), current_is_workqueue_rescuer(9), current_is_workqueue_mem_reclaim(9), workqueue_congested(9), work_busy(9), set_worker_desc(9), print_worker_info(9), show_one_workqueue(9), show_one_worker_pool(9), show_all_workqueues(9), show_freezable_workqueues(9), rebind_workers(9).
• restore_unbound_workers_cpumask(9), work_on_cpu_key(9), freeze_workqueues_begin(9), freeze_workqueues_busy(9), thaw_workqueues(9), workqueue_unbound_housekeeping_update(9), workqueue_set_unbound_cpumask(9), workqueue_sysfs_register(9), workqueue_sysfs_unregister(9), workqueue_init_early(9), workqueue_init(9), llc_count_cores(9), llc_populate_cpu_shard_id(9), precompute_cache_shard_ids(9), workqueue_init_topology(9).

mwah 💋 — source/version is ./kernel, dated October 2026, and this was the mod_delayed_work_on(9) page. byeee 🫶✨