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/*
* This file is part of LEM, a Lua Event Machine.
* Copyright 2012 Emil Renner Berthing
*
* LEM is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* LEM 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with LEM. If not, see <http://www.gnu.org/licenses/>.
*/
static unsigned int pool_jobs;
static unsigned int pool_min;
static unsigned int pool_max;
static unsigned int pool_threads;
static time_t pool_delay;
static pthread_mutex_t pool_mutex;
#if _POSIX_SPIN_LOCKS >= 200112L
static pthread_spinlock_t pool_dlock;
#define pool_done_init() pthread_spin_init(&pool_dlock, PTHREAD_PROCESS_PRIVATE)
#define pool_done_lock() pthread_spin_lock(&pool_dlock)
#define pool_done_unlock() pthread_spin_unlock(&pool_dlock)
#else
static pthread_mutex_t pool_dlock;
#define pool_done_init() pthread_mutex_init(&pool_dlock, NULL)
#define pool_done_lock() pthread_mutex_lock(&pool_dlock)
#define pool_done_unlock() pthread_mutex_unlock(&pool_dlock)
#endif
static pthread_cond_t pool_cond;
static struct lem_async *pool_head;
static struct lem_async *pool_tail;
static struct lem_async *pool_done;
static struct ev_async pool_watch;
static void *
pool_threadfunc(void *arg)
{
struct lem_async *a;
struct timespec ts;
struct timeval tv;
(void)arg;
while (1) {
gettimeofday(&tv, NULL);
ts.tv_sec = tv.tv_sec + pool_delay;
ts.tv_nsec = 1000*tv.tv_usec;
pthread_mutex_lock(&pool_mutex);
while ((a = pool_head) == NULL) {
if (pool_threads <= pool_min) {
pthread_cond_wait(&pool_cond, &pool_mutex);
continue;
}
if (pthread_cond_timedwait(&pool_cond, &pool_mutex, &ts)
&& pool_threads > pool_min)
goto out;
}
pool_head = a->next;
pthread_mutex_unlock(&pool_mutex);
lem_debug("Running job %p", a);
a->work(a);
lem_debug("Bye %p", a);
pool_done_lock();
a->next = pool_done;
pool_done = a;
pool_done_unlock();
ev_async_send(LEM_ &pool_watch);
}
out:
pool_threads--;
pthread_mutex_unlock(&pool_mutex);
return NULL;
}
static void
pool_cb(EV_P_ struct ev_async *w, int revents)
{
struct lem_async *a;
struct lem_async *next;
(void)revents;
pool_done_lock();
a = pool_done;
pool_done = NULL;
pool_done_unlock();
for (; a; a = next) {
pool_jobs--;
next = a->next;
if (a->reap)
a->reap(a);
else
free(a);
}
if (pool_jobs == 0)
ev_async_stop(EV_A_ w);
}
static int
pool_init(void)
{
int ret;
/*
pool_jobs = 0;
pool_min = 0;
pool_threads = 0;
*/
pool_max = INT_MAX;
pool_delay = 10;
/*
pool_head = NULL;
pool_tail = NULL;
pool_done = NULL;
*/
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
ev_async_init(&pool_watch, pool_cb);
#pragma GCC diagnostic pop
ret = pthread_mutex_init(&pool_mutex, NULL);
if (ret == 0)
ret = pool_done_init();
if (ret) {
lem_log_error("error initializing lock: %s",
strerror(ret));
return -1;
}
ret = pthread_cond_init(&pool_cond, NULL);
if (ret) {
lem_log_error("error initializing cond: %s",
strerror(ret));
return -1;
}
return 0;
}
static void
pool_spawnthread(void)
{
pthread_attr_t attr;
pthread_t thread;
int ret;
ret = pthread_attr_init(&attr);
if (ret)
goto error;
ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
if (ret) {
pthread_attr_destroy(&attr);
goto error;
}
ret = pthread_create(&thread, &attr, pool_threadfunc, NULL);
pthread_attr_destroy(&attr);
if (ret)
goto error;
return;
error:
lem_log_error("error spawning thread: %s", strerror(ret));
lem_exit(EXIT_FAILURE);
}
void
lem_async_run(struct lem_async *a)
{
int spawn = 0;
if (pool_jobs == 0)
ev_async_start(LEM_ &pool_watch);
pool_jobs++;
a->next = NULL;
pthread_mutex_lock(&pool_mutex);
if (pool_head == NULL) {
pool_head = a;
pool_tail = a;
} else {
pool_tail->next = a;
pool_tail = a;
}
if (pool_jobs > pool_threads && pool_threads < pool_max) {
pool_threads++;
spawn = 1;
}
pthread_mutex_unlock(&pool_mutex);
pthread_cond_signal(&pool_cond);
if (spawn)
pool_spawnthread();
}
void
lem_async_config(int delay, int min, int max)
{
int spawn;
pool_delay = (time_t)delay;
pool_min = min;
pool_max = max;
pthread_mutex_lock(&pool_mutex);
spawn = min - pool_threads;
if (spawn > 0)
pool_threads = min;
pthread_mutex_unlock(&pool_mutex);
for (; spawn > 0; spawn--)
pool_spawnthread();
}
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