STRUCT ALARM_BASE(9)

💅 struct alarm_base(9) 💅

okay bestie, buckle up — this one's from the Kernel API Manual, section 9, and it's giving "the actual skeleton of the alarm timer system". no cap, it's lowkey iconic. 🎀

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✨ NAME ✨

struct alarm_base — the alarm timer bases, periodt. that's it, that's the whole vibe. 🔥

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🌸 SYNOPSIS 🌸

struct alarm_base {
    spinlock_t lock;
    struct timerqueue_head  timerqueue;
    ktime_t (*get_ktime)(void);
    void (*get_timespec)(struct timespec64 *tp);
    clockid_t base_clockid;
 };

like, look at her. five members. main character energy. 👑

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🦋 Members 🦋

• lock — the spinlock that keeps everything synchronized when people are touching the base at the same time. she's the bouncer at the door, fr fr. 🔒
• timerqueue — a struct timerqueue_head that manages the actual list of events. this is where all the pending alarms are hanging out. 💅
• get_ktime — a function pointer that reads the time correlating to this base, and hands it back as a ktime_t. ✨
• get_timespec — a function pointer that reads the namespace time correlating to the base, writing it into a struct timespec64 *tp. so yes, it returns via the pointer, don't @ me. 🫶
• base_clockid — a clockid_t for the base. the clock identity. her little name tag. 🎀

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👑 SEE ALSO 👑

the kernel file lives at ./kernel/time/alarmtimer.c, and honestly the whole friend group is here. all of these, no skips:

• alarmtimer_get_rtcdev(9)
• alarmtimer_enqueue(9)
• alarmtimer_dequeue(9)
• alarmtimer_fired(9)
• alarmtimer_suspend(9)
• alarm_init(9)
• alarm_start_timer(9)
• alarm_try_to_cancel(9)
• alarm_cancel(9)
• clock2alarm(9)
• alarm_handle_timer(9)
• alarm_timer_rearm(9)
• alarm_timer_forward(9)
• alarm_timer_remaining(9)
• alarm_timer_try_to_cancel(9)
• alarm_timer_wait_running(9)
• alarm_timer_arm(9)
• alarm_clock_getres(9)
• alarm_clock_get_timespec(9)
• alarm_clock_get_ktime(9)
• alarm_timer_create(9)
• alarmtimer_nsleep_wakeup(9)
• alarmtimer_do_nsleep(9)
• alarm_timer_nsleep_restart(9)
• alarm_timer_nsleep(9)
• alarmtimer_init(9)

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ok that's the whole page, bestie. go read your timers. 🧚💜

and for the cute sign-off: this lil beauty comes from ./kernel/time, dated October 2026 — so go forth and alarm, queen. 🌈⭐🍓