/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <assert.h>
#include "apr_thread_pool.h"
#include "apr_ring.h"
#include "apr_thread_cond.h"
#include "apr_portable.h"
#if APR_HAS_THREADS
#define TASK_PRIORITY_SEGS 4
#define TASK_PRIORITY_SEG(x) (((x)->dispatch.priority & 0xFF) / 64)
typedef struct apr_thread_pool_task
{
APR_RING_ENTRY(apr_thread_pool_task) link;
apr_thread_start_t func;
void *param;
void *owner;
union
{
apr_byte_t priority;
apr_time_t time;
} dispatch;
} apr_thread_pool_task_t;
APR_RING_HEAD(apr_thread_pool_tasks, apr_thread_pool_task);
struct apr_thread_list_elt
{
APR_RING_ENTRY(apr_thread_list_elt) link;
apr_thread_t *thd;
volatile void *current_owner;
volatile enum { TH_RUN, TH_STOP, TH_PROBATION } state;
};
APR_RING_HEAD(apr_thread_list, apr_thread_list_elt);
struct apr_thread_pool
{
apr_pool_t *pool;
volatile apr_size_t thd_max;
volatile apr_size_t idle_max;
volatile apr_interval_time_t idle_wait;
volatile apr_size_t thd_cnt;
volatile apr_size_t idle_cnt;
volatile apr_size_t task_cnt;
volatile apr_size_t scheduled_task_cnt;
volatile apr_size_t threshold;
volatile apr_size_t tasks_run;
volatile apr_size_t tasks_high;
volatile apr_size_t thd_high;
volatile apr_size_t thd_timed_out;
struct apr_thread_pool_tasks *tasks;
struct apr_thread_pool_tasks *scheduled_tasks;
struct apr_thread_list *busy_thds;
struct apr_thread_list *idle_thds;
apr_thread_mutex_t *lock;
apr_thread_cond_t *cond;
volatile int terminated;
struct apr_thread_pool_tasks *recycled_tasks;
struct apr_thread_list *recycled_thds;
apr_thread_pool_task_t *task_idx[TASK_PRIORITY_SEGS];
};
static apr_status_t thread_pool_construct(apr_thread_pool_t * me,
apr_size_t init_threads,
apr_size_t max_threads)
{
apr_status_t rv;
int i;
me->thd_max = max_threads;
me->idle_max = init_threads;
me->threshold = init_threads / 2;
rv = apr_thread_mutex_create(&me->lock, APR_THREAD_MUTEX_NESTED,
me->pool);
if (APR_SUCCESS != rv) {
return rv;
}
rv = apr_thread_cond_create(&me->cond, me->pool);
if (APR_SUCCESS != rv) {
apr_thread_mutex_destroy(me->lock);
return rv;
}
me->tasks = apr_palloc(me->pool, sizeof(*me->tasks));
if (!me->tasks) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->tasks, apr_thread_pool_task, link);
me->scheduled_tasks = apr_palloc(me->pool, sizeof(*me->scheduled_tasks));
if (!me->scheduled_tasks) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->scheduled_tasks, apr_thread_pool_task, link);
me->recycled_tasks = apr_palloc(me->pool, sizeof(*me->recycled_tasks));
if (!me->recycled_tasks) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->recycled_tasks, apr_thread_pool_task, link);
me->busy_thds = apr_palloc(me->pool, sizeof(*me->busy_thds));
if (!me->busy_thds) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->busy_thds, apr_thread_list_elt, link);
me->idle_thds = apr_palloc(me->pool, sizeof(*me->idle_thds));
if (!me->idle_thds) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->idle_thds, apr_thread_list_elt, link);
me->recycled_thds = apr_palloc(me->pool, sizeof(*me->recycled_thds));
if (!me->recycled_thds) {
goto CATCH_ENOMEM;
}
APR_RING_INIT(me->recycled_thds, apr_thread_list_elt, link);
me->thd_cnt = me->idle_cnt = me->task_cnt = me->scheduled_task_cnt = 0;
me->tasks_run = me->tasks_high = me->thd_high = me->thd_timed_out = 0;
me->idle_wait = 0;
me->terminated = 0;
for (i = 0; i < TASK_PRIORITY_SEGS; i++) {
me->task_idx[i] = NULL;
}
goto FINAL_EXIT;
CATCH_ENOMEM:
rv = APR_ENOMEM;
apr_thread_mutex_destroy(me->lock);
apr_thread_cond_destroy(me->cond);
FINAL_EXIT:
return rv;
}
/*
* NOTE: This function is not thread safe by itself. Caller should hold the lock
*/
static apr_thread_pool_task_t *pop_task(apr_thread_pool_t * me)
{
apr_thread_pool_task_t *task = NULL;
int seg;
/* check for scheduled tasks */
if (me->scheduled_task_cnt > 0) {
task = APR_RING_FIRST(me->scheduled_tasks);
assert(task != NULL);
assert(task !=
APR_RING_SENTINEL(me->scheduled_tasks, apr_thread_pool_task,
link));
/* if it's time */
if (task->dispatch.time <= apr_time_now()) {
--me->scheduled_task_cnt;
APR_RING_REMOVE(task, link);
return task;
}
}
/* check for normal tasks if we're not returning a scheduled task */
if (me->task_cnt == 0) {
return NULL;
}
task = APR_RING_FIRST(me->tasks);
assert(task != NULL);
assert(task != APR_RING_SENTINEL(me->tasks, apr_thread_pool_task, link));
--me->task_cnt;
seg = TASK_PRIORITY_SEG(task);
if (task == me->task_idx[seg]) {
me->task_idx[seg] = APR_RING_NEXT(task, link);
if (me->task_idx[seg] == APR_RING_SENTINEL(me->tasks,
apr_thread_pool_task, link)
|| TASK_PRIORITY_SEG(me->task_idx[seg]) != seg) {
me->task_idx[seg] = NULL;
}
}
APR_RING_REMOVE(task, link);
return task;
}
static apr_interval_time_t waiting_time(apr_thread_pool_t * me)
{
apr_thread_pool_task_t *task = NULL;
task = APR_RING_FIRST(me->scheduled_tasks);
assert(task != NULL);
assert(task !=
APR_RING_SENTINEL(me->scheduled_tasks, apr_thread_pool_task,
link));
return task->dispatch.time - apr_time_now();
}
/*
* NOTE: This function is not thread safe by itself. Caller should hold the lock
*/
static struct apr_thread_list_elt *elt_new(apr_thread_pool_t * me,
apr_thread_t * t)
{
struct apr_thread_list_elt *elt;
if (APR_RING_EMPTY(me->recycled_thds, apr_thread_list_elt, link)) {
elt = apr_pcalloc(me->pool, sizeof(*elt));
if (NULL == elt) {
return NULL;
}
}
else {
elt = APR_RING_FIRST(me->recycled_thds);
APR_RING_REMOVE(elt, link);
}
APR_RING_ELEM_INIT(elt, link);
elt->thd = t;
elt->current_owner = NULL;
elt->state = TH_RUN;
return elt;
}
/*
* The worker thread function. Take a task from the queue and perform it if
* there is any. Otherwise, put itself into the idle thread list and waiting
* for signal to wake up.
* The thread terminate directly by detach and exit when it is asked to stop
* after finishing a task. Otherwise, the thread should be in idle thread list
* and should be joined.
*/
static void *APR_THREAD_FUNC thread_pool_func(apr_thread_t * t, void *param)
{
apr_thread_pool_t *me = param;
apr_thread_pool_task_t *task = NULL;
apr_interval_time_t wait;
struct apr_thread_list_elt *elt;
apr_thread_mutex_lock(me->lock);
elt = elt_new(me, t);
if (!elt) {
apr_thread_mutex_unlock(me->lock);
apr_thread_exit(t, APR_ENOMEM);
}
while (!me->terminated && elt->state != TH_STOP) {
/* Test if not new element, it is awakened from idle */
if (APR_RING_NEXT(elt, link) != elt) {
--me->idle_cnt;
APR_RING_REMOVE(elt, link);
}
APR_RING_INSERT_TAIL(me->busy_thds, elt, apr_thread_list_elt, link);
task = pop_task(me);
while (NULL != task && !me->terminated) {
++me->tasks_run;
elt->current_owner = task->owner;
apr_thread_mutex_unlock(me->lock);
apr_thread_data_set(task, "apr_thread_pool_task", NULL, t);
task->func(t, task->param);
apr_thread_mutex_lock(me->lock);
APR_RING_INSERT_TAIL(me->recycled_tasks, task,
apr_thread_pool_task, link);
elt->current_owner = NULL;
if (TH_STOP == elt->state) {
break;
}
task = pop_task(me);
}
assert(NULL == elt->current_owner);
if (TH_STOP != elt->state)
APR_RING_REMOVE(elt, link);
/* Test if a busy thread been asked to stop, which is not joinable */
if ((me->idle_cnt >= me->idle_max
&& !(me->scheduled_task_cnt && 0 >= me->idle_max)
&& !me->idle_wait)
|| me->terminated || elt->state != TH_RUN) {
--me->thd_cnt;
if ((TH_PROBATION == elt->state) && me->idle_wait)
++me->thd_timed_out;
APR_RING_INSERT_TAIL(me->recycled_thds, elt,
apr_thread_list_elt, link);
apr_thread_mutex_unlock(me->lock);
apr_thread_detach(t);
apr_thread_exit(t, APR_SUCCESS);
return NULL; /* should not be here, safe net */
}
/* busy thread become idle */
++me->idle_cnt;
APR_RING_INSERT_TAIL(me->idle_thds, elt, apr_thread_list_elt, link);
/*
* If there is a scheduled task, always scheduled to perform that task.
* Since there is no guarantee that current idle threads are scheduled
* for next scheduled task.
*/
if (me->scheduled_task_cnt)
wait = waiting_time(me);
else if (me->idle_cnt > me->idle_max) {
wait = me->idle_wait;
elt->state = TH_PROBATION;
}
else
wait = -1;
if (wait >= 0) {
apr_thread_cond_timedwait(me->cond, me->lock, wait);
}
else {
apr_thread_cond_wait(me->cond, me->lock);
}
}
/* idle thread been asked to stop, will be joined */
--me->thd_cnt;
apr_thread_mutex_unlock(me->lock);
apr_thread_exit(t, APR_SUCCESS);
return NULL; /* should not be here, safe net */
}
static apr_status_t thread_pool_cleanup(void *me)
{
apr_thread_pool_t *_myself = me;
_myself->terminated = 1;
apr_thread_pool_idle_max_set(_myself, 0);
while (_myself->thd_cnt) {
apr_sleep(20 * 1000); /* spin lock with 20 ms */
}
apr_thread_mutex_destroy(_myself->lock);
apr_thread_cond_destroy(_myself->cond);
return APR_SUCCESS;
}
APU_DECLARE(apr_status_t) apr_thread_pool_create(apr_thread_pool_t ** me,
apr_size_t init_threads,
apr_size_t max_threads,
apr_pool_t * pool)
{
apr_thread_t *t;
apr_status_t rv = APR_SUCCESS;
apr_thread_pool_t *tp;
*me = NULL;
tp = apr_pcalloc(pool, sizeof(apr_thread_pool_t));
/*
* This pool will be used by different threads. As we cannot ensure that
* our caller won't use the pool without acquiring the mutex, we must
* create a new sub pool.
*/
rv = apr_pool_create(&tp->pool, pool);
if (APR_SUCCESS != rv)
return rv;
rv = thread_pool_construct(tp, init_threads, max_threads);
if (APR_SUCCESS != rv)
return rv;
apr_pool_pre_cleanup_register(tp->pool, tp, thread_pool_cleanup);
while (init_threads) {
/* Grab the mutex as apr_thread_create() and thread_pool_func() will
* allocate from (*me)->pool. This is dangerous if there are multiple
* initial threads to create.
*/
apr_thread_mutex_lock(tp->lock);
rv = apr_thread_create(&t, NULL, thread_pool_func, tp, tp->pool);
apr_thread_mutex_unlock(tp->lock);
if (APR_SUCCESS != rv) {
break;
}
tp->thd_cnt++;
if (tp->thd_cnt > tp->thd_high) {
tp->thd_high = tp->thd_cnt;
}
--init_threads;
}
if (rv == APR_SUCCESS) {
*me = tp;
}
return rv;
}
APU_DECLARE(apr_status_t) apr_thread_pool_destroy(apr_thread_pool_t * me)
{
apr_pool_destroy(me->pool);
return APR_SUCCESS;
}
/*
* NOTE: This function is not thread safe by itself. Caller should hold the lock
*/
static apr_thread_pool_task_t *task_new(apr_thread_pool_t * me,
apr_thread_start_t func,
void *param, apr_byte_t priority,
void *owner, apr_time_t time)
{
apr_thread_pool_task_t *t;
if (APR_RING_EMPTY(me->recycled_tasks, apr_thread_pool_task, link)) {
t = apr_pcalloc(me->pool, sizeof(*t));
if (NULL == t) {
return NULL;
}
}
else {
t = APR_RING_FIRST(me->recycled_tasks);
APR_RING_REMOVE(t, link);
}
APR_RING_ELEM_INIT(t, link);
t->func = func;
t->param = param;
t->owner = owner;
if (time > 0) {
t->dispatch.time = apr_time_now() + time;
}
else {
t->dispatch.priority = priority;
}
return t;
}
/*
* Test it the task is the only one within the priority segment.
* If it is not, return the first element with same or lower priority.
* Otherwise, add the task into the queue and return NULL.
*
* NOTE: This function is not thread safe by itself. Caller should hold the lock
*/
static apr_thread_pool_task_t *add_if_empty(apr_thread_pool_t * me,
apr_thread_pool_task_t * const t)
{
int seg;
int next;
apr_thread_pool_task_t *t_next;
seg = TASK_PRIORITY_SEG(t);
if (me->task_idx[seg]) {
assert(APR_RING_SENTINEL(me->tasks, apr_thread_pool_task, link) !=
me->task_idx[seg]);
t_next = me->task_idx[seg];
while (t_next->dispatch.priority > t->dispatch.priority) {
t_next = APR_RING_NEXT(t_next, link);
if (APR_RING_SENTINEL(me->tasks, apr_thread_pool_task, link) ==
t_next) {
return t_next;
}
}
return t_next;
}
for (next = seg - 1; next >= 0; next--) {
if (me->task_idx[next]) {
APR_RING_INSERT_BEFORE(me->task_idx[next], t, link);
break;
}
}
if (0 > next) {
APR_RING_INSERT_TAIL(me->tasks, t, apr_thread_pool_task, link);
}
me->task_idx[seg] = t;
return NULL;
}
/*
* schedule a task to run in "time" microseconds. Find the spot in the ring where
* the time fits. Adjust the short_time so the thread wakes up when the time is reached.
*/
static apr_status_t schedule_task(apr_thread_pool_t *me,
apr_thread_start_t func, void *param,
void *owner, apr_interval_time_t time)
{
apr_thread_pool_task_t *t;
apr_thread_pool_task_t *t_loc;
apr_thread_t *thd;
apr_status_t rv = APR_SUCCESS;
apr_thread_mutex_lock(me->lock);
t = task_new(me, func, param, 0, owner, time);
if (NULL == t) {
apr_thread_mutex_unlock(me->lock);
return APR_ENOMEM;
}
t_loc = APR_RING_FIRST(me->scheduled_tasks);
while (NULL != t_loc) {
/* if the time is less than the entry insert ahead of it */
if (t->dispatch.time < t_loc->dispatch.time) {
++me->scheduled_task_cnt;
APR_RING_INSERT_BEFORE(t_loc, t, link);
break;
}
else {
t_loc = APR_RING_NEXT(t_loc, link);
if (t_loc ==
APR_RING_SENTINEL(me->scheduled_tasks, apr_thread_pool_task,
link)) {
++me->scheduled_task_cnt;
APR_RING_INSERT_TAIL(me->scheduled_tasks, t,
apr_thread_pool_task, link);
break;
}
}
}
/* there should be at least one thread for scheduled tasks */
if (0 == me->thd_cnt) {
rv = apr_thread_create(&thd, NULL, thread_pool_func, me, me->pool);
if (APR_SUCCESS == rv) {
++me->thd_cnt;
if (me->thd_cnt > me->thd_high)
me->thd_high = me->thd_cnt;
}
}
apr_thread_cond_signal(me->cond);
apr_thread_mutex_unlock(me->lock);
return rv;
}
static apr_status_t add_task(apr_thread_pool_t *me, apr_thread_start_t func,
void *param, apr_byte_t priority, int push,
void *owner)
{
apr_thread_pool_task_t *t;
apr_thread_pool_task_t *t_loc;
apr_thread_t *thd;
apr_status_t rv = APR_SUCCESS;
apr_thread_mutex_lock(me->lock);
t = task_new(me, func, param, priority, owner, 0);
if (NULL == t) {
apr_thread_mutex_unlock(me->lock);
return APR_ENOMEM;
}
t_loc = add_if_empty(me, t);
if (NULL == t_loc) {
goto FINAL_EXIT;
}
if (push) {
while (APR_RING_SENTINEL(me->tasks, apr_thread_pool_task, link) !=
t_loc && t_loc->dispatch.priority >= t->dispatch.priority) {
t_loc = APR_RING_NEXT(t_loc, link);
}
}
APR_RING_INSERT_BEFORE(t_loc, t, link);
if (!push) {
if (t_loc == me->task_idx[TASK_PRIORITY_SEG(t)]) {
me->task_idx[TASK_PRIORITY_SEG(t)] = t;
}
}
FINAL_EXIT:
me->task_cnt++;
if (me->task_cnt > me->tasks_high)
me->tasks_high = me->task_cnt;
if (0 == me->thd_cnt || (0 == me->idle_cnt && me->thd_cnt < me->thd_max &&
me->task_cnt > me->threshold)) {
rv = apr_thread_create(&thd, NULL, thread_pool_func, me, me->pool);
if (APR_SUCCESS == rv) {
++me->thd_cnt;
if (me->thd_cnt > me->thd_high)
me->thd_high = me->thd_cnt;
}
}
apr_thread_cond_signal(me->cond);
apr_thread_mutex_unlock(me->lock);
return rv;
}
APU_DECLARE(apr_status_t) apr_thread_pool_push(apr_thread_pool_t *me,
apr_thread_start_t func,
void *param,
apr_byte_t priority,
void *owner)
{
return add_task(me, func, param, priority, 1, owner);
}
APU_DECLARE(apr_status_t) apr_thread_pool_schedule(apr_thread_pool_t *me,
apr_thread_start_t func,
void *param,
apr_interval_time_t time,
void *owner)
{
return schedule_task(me, func, param, owner, time);
}
APU_DECLARE(apr_status_t) apr_thread_pool_top(apr_thread_pool_t *me,
apr_thread_start_t func,
void *param,
apr_byte_t priority,
void *owner)
{
return add_task(me, func, param, priority, 0, owner);
}
static apr_status_t remove_scheduled_tasks(apr_thread_pool_t *me,
void *owner)
{
apr_thread_pool_task_t *t_loc;
apr_thread_pool_task_t *next;
t_loc = APR_RING_FIRST(me->scheduled_tasks);
while (t_loc !=
APR_RING_SENTINEL(me->scheduled_tasks, apr_thread_pool_task,
link)) {
next = APR_RING_NEXT(t_loc, link);
/* if this is the owner remove it */
if (t_loc->owner == owner) {
--me->scheduled_task_cnt;
APR_RING_REMOVE(t_loc, link);
}
t_loc = next;
}
return APR_SUCCESS;
}
static apr_status_t remove_tasks(apr_thread_pool_t *me, void *owner)
{
apr_thread_pool_task_t *t_loc;
apr_thread_pool_task_t *next;
int seg;
t_loc = APR_RING_FIRST(me->tasks);
while (t_loc != APR_RING_SENTINEL(me->tasks, apr_thread_pool_task, link)) {
next = APR_RING_NEXT(t_loc, link);
if (t_loc->owner == owner) {
--me->task_cnt;
seg = TASK_PRIORITY_SEG(t_loc);
if (t_loc == me->task_idx[seg]) {
me->task_idx[seg] = APR_RING_NEXT(t_loc, link);
if (me->task_idx[seg] == APR_RING_SENTINEL(me->tasks,
apr_thread_pool_task,
link)
|| TASK_PRIORITY_SEG(me->task_idx[seg]) != seg) {
me->task_idx[seg] = NULL;
}
}
APR_RING_REMOVE(t_loc, link);
}
t_loc = next;
}
return APR_SUCCESS;
}
static void wait_on_busy_threads(apr_thread_pool_t *me, void *owner)
{
#ifndef NDEBUG
apr_os_thread_t *os_thread;
#endif
struct apr_thread_list_elt *elt;
apr_thread_mutex_lock(me->lock);
elt = APR_RING_FIRST(me->busy_thds);
while (elt != APR_RING_SENTINEL(me->busy_thds, apr_thread_list_elt, link)) {
if (elt->current_owner != owner) {
elt = APR_RING_NEXT(elt, link);
continue;
}
#ifndef NDEBUG
/* make sure the thread is not the one calling tasks_cancel */
apr_os_thread_get(&os_thread, elt->thd);
#ifdef WIN32
/* hack for apr win32 bug */
assert(!apr_os_thread_equal(apr_os_thread_current(), os_thread));
#else
assert(!apr_os_thread_equal(apr_os_thread_current(), *os_thread));
#endif
#endif
while (elt->current_owner == owner) {
apr_thread_mutex_unlock(me->lock);
apr_sleep(200 * 1000);
apr_thread_mutex_lock(me->lock);
}
elt = APR_RING_FIRST(me->busy_thds);
}
apr_thread_mutex_unlock(me->lock);
return;
}
APU_DECLARE(apr_status_t) apr_thread_pool_tasks_cancel(apr_thread_pool_t *me,
void *owner)
{
apr_status_t rv = APR_SUCCESS;
apr_thread_mutex_lock(me->lock);
if (me->task_cnt > 0) {
rv = remove_tasks(me, owner);
}
if (me->scheduled_task_cnt > 0) {
rv = remove_scheduled_tasks(me, owner);
}
apr_thread_mutex_unlock(me->lock);
wait_on_busy_threads(me, owner);
return rv;
}
APU_DECLARE(apr_size_t) apr_thread_pool_tasks_count(apr_thread_pool_t *me)
{
return me->task_cnt;
}
APU_DECLARE(apr_size_t)
apr_thread_pool_scheduled_tasks_count(apr_thread_pool_t *me)
{
return me->scheduled_task_cnt;
}
APU_DECLARE(apr_size_t) apr_thread_pool_threads_count(apr_thread_pool_t *me)
{
return me->thd_cnt;
}
APU_DECLARE(apr_size_t) apr_thread_pool_busy_count(apr_thread_pool_t *me)
{
return me->thd_cnt - me->idle_cnt;
}
APU_DECLARE(apr_size_t) apr_thread_pool_idle_count(apr_thread_pool_t *me)
{
return me->idle_cnt;
}
APU_DECLARE(apr_size_t)
apr_thread_pool_tasks_run_count(apr_thread_pool_t * me)
{
return me->tasks_run;
}
APU_DECLARE(apr_size_t)
apr_thread_pool_tasks_high_count(apr_thread_pool_t * me)
{
return me->tasks_high;
}
APU_DECLARE(apr_size_t)
apr_thread_pool_threads_high_count(apr_thread_pool_t * me)
{
return me->thd_high;
}
APU_DECLARE(apr_size_t)
apr_thread_pool_threads_idle_timeout_count(apr_thread_pool_t * me)
{
return me->thd_timed_out;
}
APU_DECLARE(apr_size_t) apr_thread_pool_idle_max_get(apr_thread_pool_t *me)
{
return me->idle_max;
}
APU_DECLARE(apr_interval_time_t)
apr_thread_pool_idle_wait_get(apr_thread_pool_t * me)
{
return me->idle_wait;
}
/*
* This function stop extra idle threads to the cnt.
* @return the number of threads stopped
* NOTE: There could be busy threads become idle during this function
*/
static struct apr_thread_list_elt *trim_threads(apr_thread_pool_t *me,
apr_size_t *cnt, int idle)
{
struct apr_thread_list *thds;
apr_size_t n, n_dbg, i;
struct apr_thread_list_elt *head, *tail, *elt;
apr_thread_mutex_lock(me->lock);
if (idle) {
thds = me->idle_thds;
n = me->idle_cnt;
}
else {
thds = me->busy_thds;
n = me->thd_cnt - me->idle_cnt;
}
if (n <= *cnt) {
apr_thread_mutex_unlock(me->lock);
*cnt = 0;
return NULL;
}
n -= *cnt;
head = APR_RING_FIRST(thds);
for (i = 0; i < *cnt; i++) {
head = APR_RING_NEXT(head, link);
}
tail = APR_RING_LAST(thds);
if (idle) {
APR_RING_UNSPLICE(head, tail, link);
me->idle_cnt = *cnt;
}
n_dbg = 0;
for (elt = head; elt != tail; elt = APR_RING_NEXT(elt, link)) {
elt->state = TH_STOP;
n_dbg++;
}
elt->state = TH_STOP;
n_dbg++;
assert(n == n_dbg);
*cnt = n;
apr_thread_mutex_unlock(me->lock);
APR_RING_PREV(head, link) = NULL;
APR_RING_NEXT(tail, link) = NULL;
return head;
}
static apr_size_t trim_idle_threads(apr_thread_pool_t *me, apr_size_t cnt)
{
apr_size_t n_dbg;
struct apr_thread_list_elt *elt, *head, *tail;
apr_status_t rv;
elt = trim_threads(me, &cnt, 1);
apr_thread_mutex_lock(me->lock);
apr_thread_cond_broadcast(me->cond);
apr_thread_mutex_unlock(me->lock);
n_dbg = 0;
if (NULL != (head = elt)) {
while (elt) {
tail = elt;
apr_thread_join(&rv, elt->thd);
elt = APR_RING_NEXT(elt, link);
++n_dbg;
}
apr_thread_mutex_lock(me->lock);
APR_RING_SPLICE_TAIL(me->recycled_thds, head, tail,
apr_thread_list_elt, link);
apr_thread_mutex_unlock(me->lock);
}
assert(cnt == n_dbg);
return cnt;
}
/* don't join on busy threads for performance reasons, who knows how long will
* the task takes to perform
*/
static apr_size_t trim_busy_threads(apr_thread_pool_t *me, apr_size_t cnt)
{
trim_threads(me, &cnt, 0);
return cnt;
}
APU_DECLARE(apr_size_t) apr_thread_pool_idle_max_set(apr_thread_pool_t *me,
apr_size_t cnt)
{
me->idle_max = cnt;
cnt = trim_idle_threads(me, cnt);
return cnt;
}
APU_DECLARE(apr_interval_time_t)
apr_thread_pool_idle_wait_set(apr_thread_pool_t * me,
apr_interval_time_t timeout)
{
apr_interval_time_t oldtime;
oldtime = me->idle_wait;
me->idle_wait = timeout;
return oldtime;
}
APU_DECLARE(apr_size_t) apr_thread_pool_thread_max_get(apr_thread_pool_t *me)
{
return me->thd_max;
}
/*
* This function stop extra working threads to the new limit.
* NOTE: There could be busy threads become idle during this function
*/
APU_DECLARE(apr_size_t) apr_thread_pool_thread_max_set(apr_thread_pool_t *me,
apr_size_t cnt)
{
unsigned int n;
me->thd_max = cnt;
if (0 == cnt || me->thd_cnt <= cnt) {
return 0;
}
n = me->thd_cnt - cnt;
if (n >= me->idle_cnt) {
trim_busy_threads(me, n - me->idle_cnt);
trim_idle_threads(me, 0);
}
else {
trim_idle_threads(me, me->idle_cnt - n);
}
return n;
}
APU_DECLARE(apr_size_t) apr_thread_pool_threshold_get(apr_thread_pool_t *me)
{
return me->threshold;
}
APU_DECLARE(apr_size_t) apr_thread_pool_threshold_set(apr_thread_pool_t *me,
apr_size_t val)
{
apr_size_t ov;
ov = me->threshold;
me->threshold = val;
return ov;
}
APU_DECLARE(apr_status_t) apr_thread_pool_task_owner_get(apr_thread_t *thd,
void **owner)
{
apr_status_t rv;
apr_thread_pool_task_t *task;
void *data;
rv = apr_thread_data_get(&data, "apr_thread_pool_task", thd);
if (rv != APR_SUCCESS) {
return rv;
}
task = data;
if (!task) {
*owner = NULL;
return APR_BADARG;
}
*owner = task->owner;
return APR_SUCCESS;
}
#endif /* APR_HAS_THREADS */
/* vim: set ts=4 sw=4 et cin tw=80: */