linux-stable/include/linux/timerqueue.h
Thomas Gleixner 60bda037f1 posix-cpu-timers: Utilize timerqueue for storage
Using a linear O(N) search for timer insertion affects execution time and
D-cache footprint badly with a larger number of timers.

Switch the storage to a timerqueue which is already used for hrtimers and
alarmtimers. It does not affect the size of struct k_itimer as it.alarm is
still larger.

The extra list head for the expiry list will go away later once the expiry
is moved into task work context.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908272129220.1939@nanos.tec.linutronix.de
2019-08-28 11:50:43 +02:00

60 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TIMERQUEUE_H
#define _LINUX_TIMERQUEUE_H
#include <linux/rbtree.h>
#include <linux/ktime.h>
struct timerqueue_node {
struct rb_node node;
ktime_t expires;
};
struct timerqueue_head {
struct rb_root_cached rb_root;
};
extern bool timerqueue_add(struct timerqueue_head *head,
struct timerqueue_node *node);
extern bool timerqueue_del(struct timerqueue_head *head,
struct timerqueue_node *node);
extern struct timerqueue_node *timerqueue_iterate_next(
struct timerqueue_node *node);
/**
* timerqueue_getnext - Returns the timer with the earliest expiration time
*
* @head: head of timerqueue
*
* Returns a pointer to the timer node that has the earliest expiration time.
*/
static inline
struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head)
{
struct rb_node *leftmost = rb_first_cached(&head->rb_root);
return rb_entry(leftmost, struct timerqueue_node, node);
}
static inline void timerqueue_init(struct timerqueue_node *node)
{
RB_CLEAR_NODE(&node->node);
}
static inline bool timerqueue_node_queued(struct timerqueue_node *node)
{
return !RB_EMPTY_NODE(&node->node);
}
static inline bool timerqueue_node_expires(struct timerqueue_node *node)
{
return node->expires;
}
static inline void timerqueue_init_head(struct timerqueue_head *head)
{
head->rb_root = RB_ROOT_CACHED;
}
#endif /* _LINUX_TIMERQUEUE_H */