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/*****************************************************************************
Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/******************************************************
Server query execution
Created 6/5/1996 Heikki Tuuri
*******************************************************/
#include "srv0que.h"
#include "srv0srv.h"
#include "sync0sync.h"
#include "os0thread.h"
#include "usr0sess.h"
#include "que0que.h"
/**************************************************************************
Checks if there is work to do in the server task queue. If there is, the
thread starts processing a task. Before leaving, it again checks the task
queue and picks a new task if any exists. This is called by a SRV_WORKER
thread. */
UNIV_INTERN
void
srv_que_task_queue_check(void)
/*==========================*/
{
que_thr_t* thr;
for (;;) {
mutex_enter(&kernel_mutex);
thr = UT_LIST_GET_FIRST(srv_sys->tasks);
if (thr == NULL) {
mutex_exit(&kernel_mutex);
return;
}
UT_LIST_REMOVE(queue, srv_sys->tasks, thr);
mutex_exit(&kernel_mutex);
que_run_threads(thr);
}
}
/**************************************************************************
Performs round-robin on the server tasks. This is called by a SRV_WORKER
thread every second or so. */
UNIV_INTERN
que_thr_t*
srv_que_round_robin(
/*================*/
/* out: the new (may be == thr) query thread
to run */
que_thr_t* thr) /* in: query thread */
{
que_thr_t* new_thr;
ut_ad(thr);
ut_ad(thr->state == QUE_THR_RUNNING);
mutex_enter(&kernel_mutex);
UT_LIST_ADD_LAST(queue, srv_sys->tasks, thr);
new_thr = UT_LIST_GET_FIRST(srv_sys->tasks);
mutex_exit(&kernel_mutex);
return(new_thr);
}
/**************************************************************************
Enqueues a task to server task queue and releases a worker thread, if there
is a suspended one. */
UNIV_INTERN
void
srv_que_task_enqueue_low(
/*=====================*/
que_thr_t* thr) /* in: query thread */
{
ut_ad(thr);
ut_ad(mutex_own(&kernel_mutex));
UT_LIST_ADD_LAST(queue, srv_sys->tasks, thr);
srv_release_threads(SRV_WORKER, 1);
}
/**************************************************************************
Enqueues a task to server task queue and releases a worker thread, if there
is a suspended one. */
UNIV_INTERN
void
srv_que_task_enqueue(
/*=================*/
que_thr_t* thr) /* in: query thread */
{
ut_ad(thr);
ut_a(0); /* Under MySQL this is never called */
mutex_enter(&kernel_mutex);
srv_que_task_enqueue_low(thr);
mutex_exit(&kernel_mutex);
}
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