release/src/router/mysql/storage/innobase/srv/srv0que.c

   1 /******************************************************
   2 Server query execution
   3
   4 (c) 1996 Innobase Oy
   5
   6 Created 6/5/1996 Heikki Tuuri
   7 *******************************************************/
   8
   9 #include "srv0que.h"
  10
  11 #include "srv0srv.h"
  12 #include "sync0sync.h"
  13 #include "os0thread.h"
  14 #include "usr0sess.h"
  15 #include "que0que.h"
  16
  17 /**************************************************************************
  18 Checks if there is work to do in the server task queue. If there is, the
  19 thread starts processing a task. Before leaving, it again checks the task
  20 queue and picks a new task if any exists. This is called by a SRV_WORKER
  21 thread. */
  22
  23 void
  24 srv_que_task_queue_check(void)
  25 /*==========================*/
  26 {
  27         que_thr_t*      thr;
  28
  29         for (;;) {
  30                 mutex_enter(&kernel_mutex);
  31
  32                 thr = UT_LIST_GET_FIRST(srv_sys->tasks);
  33
  34                 if (thr == NULL) {
  35                         mutex_exit(&kernel_mutex);
  36
  37                         return;
  38                 }
  39
  40                 UT_LIST_REMOVE(queue, srv_sys->tasks, thr);
  41
  42                 mutex_exit(&kernel_mutex);
  43
  44                 que_run_threads(thr);
  45         }
  46 }
  47
  48 /**************************************************************************
  49 Performs round-robin on the server tasks. This is called by a SRV_WORKER
  50 thread every second or so. */
  51
  52 que_thr_t*
  53 srv_que_round_robin(
  54 /*================*/
  55                                 /* out: the new (may be == thr) query thread
  56                                 to run */
  57         que_thr_t*      thr)    /* in: query thread */
  58 {
  59         que_thr_t*      new_thr;
  60
  61         ut_ad(thr);
  62         ut_ad(thr->state == QUE_THR_RUNNING);
  63
  64         mutex_enter(&kernel_mutex);
  65
  66         UT_LIST_ADD_LAST(queue, srv_sys->tasks, thr);
  67
  68         new_thr = UT_LIST_GET_FIRST(srv_sys->tasks);
  69
  70         mutex_exit(&kernel_mutex);
  71
  72         return(new_thr);
  73 }
  74
  75 /**************************************************************************
  76 Enqueues a task to server task queue and releases a worker thread, if there
  77 is a suspended one. */
  78
  79 void
  80 srv_que_task_enqueue_low(
  81 /*=====================*/
  82         que_thr_t*      thr)    /* in: query thread */
  83 {
  84         ut_ad(thr);
  85         ut_ad(mutex_own(&kernel_mutex));
  86
  87         UT_LIST_ADD_LAST(queue, srv_sys->tasks, thr);
  88
  89         srv_release_threads(SRV_WORKER, 1);
  90 }
  91
  92 /**************************************************************************
  93 Enqueues a task to server task queue and releases a worker thread, if there
  94 is a suspended one. */
  95
  96 void
  97 srv_que_task_enqueue(
  98 /*=================*/
  99         que_thr_t*      thr)    /* in: query thread */
 100 {
 101         ut_ad(thr);
 102
 103         ut_a(0);        /* Under MySQL this is never called */
 104
 105         mutex_enter(&kernel_mutex);
 106
 107         srv_que_task_enqueue_low(thr);
 108
 109         mutex_exit(&kernel_mutex);
 110 }