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/* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2012, Monty Program Ab
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/*
Implementation for the thread scheduler
*/
#ifdef USE_PRAGMA_INTERFACE
#pragma implementation
#endif
#include "sql_connect.h" // init_new_connection_handler_thread
#include "scheduler.h"
#include "mysqld.h"
#include "sql_class.h"
#include "sql_callback.h"
/*
End connection, in case when we are using 'no-threads'
*/
static bool no_threads_end(THD *thd, bool put_in_cache)
{
unlink_thd(thd);
return 1; // Abort handle_one_connection
}
/** @internal
Helper functions to allow mysys to call the thread scheduler when
waiting for locks.
*/
/**@{*/
extern "C"
{
static void scheduler_wait_lock_begin(void) {
thd_wait_begin(NULL, THD_WAIT_TABLE_LOCK);
}
static void scheduler_wait_lock_end(void) {
thd_wait_end(NULL);
}
static void scheduler_wait_sync_begin(void) {
thd_wait_begin(NULL, THD_WAIT_SYNC);
}
static void scheduler_wait_sync_end(void) {
thd_wait_end(NULL);
}
};
/**@}*/
/**
Common scheduler init function.
The scheduler is either initialized by calling
one_thread_scheduler() or one_thread_per_connection_scheduler() in
mysqld.cc, so this init function will always be called.
*/
void scheduler_init() {
thr_set_lock_wait_callback(scheduler_wait_lock_begin,
scheduler_wait_lock_end);
thr_set_sync_wait_callback(scheduler_wait_sync_begin,
scheduler_wait_sync_end);
}
/**
Kill notification callback, used by one-thread-per-connection
and threadpool scheduler.
Wakes up a thread that is stuck in read/poll/epoll/event-poll
routines used by threadpool, such that subsequent attempt to
read from client connection will result in IO error.
*/
void post_kill_notification(THD *thd)
{
DBUG_ENTER("post_kill_notification");
if (current_thd == thd || thd->system_thread)
DBUG_VOID_RETURN;
if (thd->net.vio)
vio_shutdown(thd->net.vio, SHUT_RD);
DBUG_VOID_RETURN;
}
/*
Initialize scheduler for --thread-handling=one-thread-per-connection
*/
#ifndef EMBEDDED_LIBRARY
void one_thread_per_connection_scheduler(scheduler_functions *func,
ulong *arg_max_connections,
uint *arg_connection_count)
{
scheduler_init();
func->max_threads= *arg_max_connections + 1;
func->max_connections= arg_max_connections;
func->connection_count= arg_connection_count;
func->init_new_connection_thread= init_new_connection_handler_thread;
func->add_connection= create_thread_to_handle_connection;
func->end_thread= one_thread_per_connection_end;
func->post_kill_notification= post_kill_notification;
}
#endif
/*
Initailize scheduler for --thread-handling=no-threads
*/
void one_thread_scheduler(scheduler_functions *func)
{
scheduler_init();
func->max_threads= 1;
func->max_connections= &max_connections;
func->connection_count= &connection_count;
#ifndef EMBEDDED_LIBRARY
func->init_new_connection_thread= init_new_connection_handler_thread;
func->add_connection= handle_connection_in_main_thread;
#endif
func->end_thread= no_threads_end;
}
/*
no pluggable schedulers in mariadb.
when we'll want it, we'll do it properly
*/
#if 0
static scheduler_functions *saved_thread_scheduler;
static uint saved_thread_handling;
extern "C"
int my_thread_scheduler_set(scheduler_functions *scheduler)
{
DBUG_ASSERT(scheduler != 0);
if (scheduler == NULL)
return 1;
saved_thread_scheduler= thread_scheduler;
saved_thread_handling= thread_handling;
thread_scheduler= scheduler;
// Scheduler loaded dynamically
thread_handling= SCHEDULER_TYPES_COUNT;
return 0;
}
extern "C"
int my_thread_scheduler_reset()
{
DBUG_ASSERT(saved_thread_scheduler != NULL);
if (saved_thread_scheduler == NULL)
return 1;
thread_scheduler= saved_thread_scheduler;
thread_handling= saved_thread_handling;
saved_thread_scheduler= 0;
return 0;
}
#else
extern "C" int my_thread_scheduler_set(scheduler_functions *scheduler)
{ return 1; }
extern "C" int my_thread_scheduler_reset()
{ return 1; }
#endif
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