MaxScale/server/core/housekeeper.c

326 lines
7.0 KiB
C

/*
* This file is distributed as part of the MariaDB Corporation MaxScale. It 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.
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright MariaDB Corporation Ab 2014
*/
#include <stdlib.h>
#include <string.h>
#include <housekeeper.h>
#include <thread.h>
#include <spinlock.h>
/**
* @file housekeeper.c Provide a mechanism to run periodic tasks
*
* The housekeeper provides a mechanism to allow for tasks, function
* calls basically, to be run on a tiem basis. A task may be run
* repeatedly, with a given frequency (in seconds), or may be a one
* shot task that will only be run once after a specified number of
* seconds.
*
* The housekeeper also maintains a global variable, hkheartbeat, that
* is incremented every 100ms.
*
* @verbatim
* Revision History
*
* Date Who Description
* 29/08/14 Mark Riddoch Initial implementation
* 22/10/14 Mark Riddoch Addition of one-shot tasks
*
* @endverbatim
*/
/**
* List of all tasks that need to be run
*/
static HKTASK *tasks = NULL;
/**
* Spinlock to protect the tasks list
*/
static SPINLOCK tasklock = SPINLOCK_INIT;
static int do_shutdown = 0;
unsigned long hkheartbeat = 0;
static void hkthread(void *);
/**
* Initialise the housekeeper thread
*/
void
hkinit()
{
thread_start(hkthread, NULL);
}
/**
* Add a new task to the housekeepers lists of tasks that should be
* run periodically.
*
* The task will be first run frequency seconds after this call is
* made and will the be executed repeatedly every frequency seconds
* until the task is removed.
*
* Task names must be unique.
*
* @param name The unique name for this housekeeper task
* @param taskfn The function to call for the task
* @param data Data to pass to the task function
* @param frequency How often to run the task, expressed in seconds
* @return Return the time in seconds when the task will be first run if the task was added, otherwise 0
*/
int
hktask_add(char *name, void (*taskfn)(void *), void *data, int frequency)
{
HKTASK *task, *ptr;
if ((task = (HKTASK *)malloc(sizeof(HKTASK))) == NULL)
{
return 0;
}
if ((task->name = strdup(name)) == NULL)
{
free(task);
return 0;
}
task->task = taskfn;
task->data = data;
task->frequency = frequency;
task->type = HK_REPEATED;
task->nextdue = time(0) + frequency;
task->next = NULL;
spinlock_acquire(&tasklock);
ptr = tasks;
while (ptr && ptr->next)
{
if (strcmp(ptr->name, name) == 0)
{
spinlock_release(&tasklock);
free(task->name);
free(task);
return 0;
}
ptr = ptr->next;
}
if (ptr)
{
if (strcmp(ptr->name, name) == 0)
{
spinlock_release(&tasklock);
free(task->name);
free(task);
return 0;
}
ptr->next = task;
}
else
{
tasks = task;
}
spinlock_release(&tasklock);
return task->nextdue;
}
/**
* Add a one-shot task to the housekeeper task list
*
* Task names must be unique.
*
* @param name The unique name for this housekeeper task
* @param taskfn The function to call for the task
* @param data Data to pass to the task function
* @param when How many second until the task is executed
* @return Return the time in seconds when the task will be first run if the task was added, otherwise 0
*
*/
int
hktask_oneshot(char *name, void (*taskfn)(void *), void *data, int when)
{
HKTASK *task, *ptr;
if ((task = (HKTASK *)malloc(sizeof(HKTASK))) == NULL)
{
return 0;
}
if ((task->name = strdup(name)) == NULL)
{
free(task);
return 0;
}
task->task = taskfn;
task->data = data;
task->frequency = 0;
task->type = HK_ONESHOT;
task->nextdue = time(0) + when;
task->next = NULL;
spinlock_acquire(&tasklock);
ptr = tasks;
while (ptr && ptr->next)
{
if (strcmp(ptr->name, name) == 0)
{
spinlock_release(&tasklock);
free(task->name);
free(task);
return 0;
}
ptr = ptr->next;
}
if (ptr)
ptr->next = task;
else
tasks = task;
spinlock_release(&tasklock);
return task->nextdue;
}
/**
* Remove a named task from the housekeepers task list
*
* @param name The task name to remove
* @return Returns 0 if the task could not be removed
*/
int
hktask_remove(char *name)
{
HKTASK *ptr, *lptr = NULL;
spinlock_acquire(&tasklock);
ptr = tasks;
while (ptr && strcmp(ptr->name, name) != 0)
{
lptr = ptr;
ptr = ptr->next;
}
if (ptr && lptr)
lptr->next = ptr->next;
else if (ptr)
tasks = ptr->next;
spinlock_release(&tasklock);
if (ptr)
{
free(ptr->name);
free(ptr);
return 1;
}
else
{
return 0;
}
}
/**
* The housekeeper thread implementation.
*
* This function is responsible for executing the housekeeper tasks.
*
* The implementation of the callng of the task functions is such that
* the tasks are called without the tasklock spinlock being held. This
* allows manipulation of the housekeeper task list during execution of
* one of the tasks. The resutl is that upon completion of a task the
* search for tasks to run must restart from the start of the queue.
* It is vital that the task->nextdue tiem is updated before the task
* is run.
*
* @param data Unused, here to satisfy the thread system
*/
void
hkthread(void *data)
{
HKTASK *ptr;
time_t now;
void (*taskfn)(void *);
void *taskdata;
int i;
for (;;)
{
for (i = 0; i < 10; i++)
{
if (do_shutdown)
return;
thread_millisleep(100);
hkheartbeat++;
}
now = time(0);
spinlock_acquire(&tasklock);
ptr = tasks;
while (ptr)
{
if (ptr->nextdue <= now)
{
ptr->nextdue = now + ptr->frequency;
taskfn = ptr->task;
taskdata = ptr->data;
spinlock_release(&tasklock);
(*taskfn)(taskdata);
if (ptr->type == HK_ONESHOT)
hktask_remove(ptr->name);
spinlock_acquire(&tasklock);
ptr = tasks;
}
else
ptr = ptr->next;
}
spinlock_release(&tasklock);
}
}
/**
* Called to shutdown the housekeeper
*
*/
void
hkshutdown()
{
do_shutdown = 1;
}
/**
* Show the tasks that are scheduled for the house keeper
*
* @param pdcb The DCB to send to output
*/
void
hkshow_tasks(DCB *pdcb)
{
HKTASK *ptr;
struct tm tm;
char buf[40];
dcb_printf(pdcb, "%-25s | Type | Frequency | Next Due\n", "Name");
dcb_printf(pdcb, "--------------------------+----------+-----------+-------------------------\n");
spinlock_acquire(&tasklock);
ptr = tasks;
while (ptr)
{
localtime_r(&ptr->nextdue, &tm);
asctime_r(&tm, buf);
dcb_printf(pdcb, "%-25s | %-8s | %-9d | %s",
ptr->name,
ptr->type == HK_REPEATED ? "Repeated" : "One-Shot",
ptr->frequency,
buf);
ptr = ptr->next;
}
spinlock_release(&tasklock);
}