nginx/src/event/ngx_event_timer.h

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  */
   5
   6
   7 #ifndef _NGX_EVENT_TIMER_H_INCLUDED_
   8 #define _NGX_EVENT_TIMER_H_INCLUDED_
   9
  10
  11 #include <ngx_config.h>
  12 #include <ngx_core.h>
  13 #include <ngx_event.h>
  14
  15
  16 #define NGX_TIMER_INFINITE  (ngx_msec_t) -1
  17
  18 #define NGX_TIMER_LAZY_DELAY  300
  19
  20
  21 ngx_int_t ngx_event_timer_init(ngx_log_t *log);
  22 ngx_msec_t ngx_event_find_timer(void);
  23 void ngx_event_expire_timers(void);
  24
  25
  26 #if (NGX_THREADS)
  27 extern ngx_mutex_t  *ngx_event_timer_mutex;
  28 #endif
  29
  30
  31 extern ngx_thread_volatile ngx_rbtree_t  ngx_event_timer_rbtree;
  32
  33
  34 static ngx_inline void
  35 ngx_event_del_timer(ngx_event_t *ev)
  36 {
  37     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
  38                    "event timer del: %d: %M",
  39                     ngx_event_ident(ev->data), ev->timer.key);
  40
  41     ngx_mutex_lock(ngx_event_timer_mutex);
  42
  43     ngx_rbtree_delete(&ngx_event_timer_rbtree, &ev->timer);
  44
  45     ngx_mutex_unlock(ngx_event_timer_mutex);
  46
  47 #if (NGX_DEBUG)
  48     ev->timer.left = NULL;
  49     ev->timer.right = NULL;
  50     ev->timer.parent = NULL;
  51 #endif
  52
  53     ev->timer_set = 0;
  54 }
  55
  56
  57 static ngx_inline void
  58 ngx_event_add_timer(ngx_event_t *ev, ngx_msec_t timer)
  59 {
  60     ngx_msec_t      key;
  61     ngx_msec_int_t  diff;
  62
  63     key = ngx_current_msec + timer;
  64
  65     if (ev->timer_set) {
  66
  67         /*
  68          * Use a previous timer value if difference between it and a new
  69          * value is less than NGX_TIMER_LAZY_DELAY milliseconds: this allows
  70          * to minimize the rbtree operations for fast connections.
  71          */
  72
  73         diff = (ngx_msec_int_t) (key - ev->timer.key);
  74
  75         if (ngx_abs(diff) < NGX_TIMER_LAZY_DELAY) {
  76             ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
  77                            "event timer: %d, old: %M, new: %M",
  78                             ngx_event_ident(ev->data), ev->timer.key, key);
  79             return;
  80         }
  81
  82         ngx_del_timer(ev);
  83     }
  84
  85     ev->timer.key = key;
  86
  87     ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
  88                    "event timer add: %d: %M:%M",
  89                     ngx_event_ident(ev->data), timer, ev->timer.key);
  90
  91     ngx_mutex_lock(ngx_event_timer_mutex);
  92
  93     ngx_rbtree_insert(&ngx_event_timer_rbtree, &ev->timer);
  94
  95     ngx_mutex_unlock(ngx_event_timer_mutex);
  96
  97     ev->timer_set = 1;
  98 }
  99
 100
 101 #endif /* _NGX_EVENT_TIMER_H_INCLUDED_ */