include/linux/alarmtimer.h

File Facts

System

Linux kernel

Corpus path

include/linux/alarmtimer.h

Extension

.h

Size

1902 bytes

Lines

68

Domain

Core OS

Bucket

Core Kernel Interface

Inferred role

Core OS: implementation source

Status

source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/time.h
• linux/hrtimer.h
• linux/timerqueue.h

Detected Declarations

• struct rtc_device
• struct alarm
• enum alarmtimer_type
• function alarm_get_expires

Annotated Snippet

struct alarm {
	struct timerqueue_node	node;
	struct hrtimer		timer;
	void			(*function)(struct alarm *, ktime_t now);
	enum alarmtimer_type	type;
	int			state;
	void			*data;
};

static __always_inline ktime_t alarm_get_expires(struct alarm *alarm)
{
	return alarm->node.expires;
}

void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
		void (*function)(struct alarm *, ktime_t));
bool alarm_start_timer(struct alarm *alarm, ktime_t expires, bool relative);
int alarm_try_to_cancel(struct alarm *alarm);
int alarm_cancel(struct alarm *alarm);

u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
u64 alarm_forward_now(struct alarm *alarm, ktime_t interval);
ktime_t alarm_expires_remaining(const struct alarm *alarm);

#ifdef CONFIG_RTC_CLASS
/* Provide way to access the rtc device being used by alarmtimers */
struct rtc_device *alarmtimer_get_rtcdev(void);
#else
static inline struct rtc_device *alarmtimer_get_rtcdev(void) { return NULL; }
#endif

#endif

Annotation

• Immediate include surface: `linux/time.h`, `linux/hrtimer.h`, `linux/timerqueue.h`.
• Detected declarations: `struct rtc_device`, `struct alarm`, `enum alarmtimer_type`, `function alarm_get_expires`.
• Atlas domain: Core OS / Core Kernel Interface.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.