1 files changed, 430 insertions, 0 deletions
diff --git a/cddl/compat/opensolaris/misc/thread_pool.c b/cddl/compat/opensolaris/misc/thread_pool.c
new file mode 100644
index 000000000000..a6a834fb2bbd
--- /dev/null
+++ b/cddl/compat/opensolaris/misc/thread_pool.c
@@ -0,0 +1,430 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <stdlib.h>
+#include <signal.h>
+#include <errno.h>
+#include "thread_pool_impl.h"
+
+typedef void (*_Voidfp)(void*); /* pointer to extern "C" function */
+
+static void
+delete_pool(tpool_t *tpool)
+{
+	tpool_job_t *job;
+
+	/*
+	 * There should be no pending jobs, but just in case...
+	 */
+	for (job = tpool->tp_head; job != NULL; job = tpool->tp_head) {
+		tpool->tp_head = job->tpj_next;
+		free(job);
+	}
+	(void) pthread_attr_destroy(&tpool->tp_attr);
+	free(tpool);
+}
+
+/*
+ * Worker thread is terminating.
+ */
+static void
+worker_cleanup(void *arg)
+{
+	tpool_t *tpool = arg;
+
+	if (--tpool->tp_current == 0 &&
+	    (tpool->tp_flags & (TP_DESTROY | TP_ABANDON))) {
+		if (tpool->tp_flags & TP_ABANDON) {
+			pthread_mutex_unlock(&tpool->tp_mutex);
+			delete_pool(tpool);
+			return;
+		}
+		if (tpool->tp_flags & TP_DESTROY)
+			(void) pthread_cond_broadcast(&tpool->tp_busycv);
+	}
+	pthread_mutex_unlock(&tpool->tp_mutex);
+}
+
+static void
+notify_waiters(tpool_t *tpool)
+{
+	if (tpool->tp_head == NULL && tpool->tp_active == NULL) {
+		tpool->tp_flags &= ~TP_WAIT;
+		(void) pthread_cond_broadcast(&tpool->tp_waitcv);
+	}
+}
+
+/*
+ * Called by a worker thread on return from a tpool_dispatch()d job.
+ */
+static void
+job_cleanup(void *arg)
+{
+	tpool_t *tpool = arg;
+	pthread_t my_tid = pthread_self();
+	tpool_active_t *activep;
+	tpool_active_t **activepp;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	/* CSTYLED */
+	for (activepp = &tpool->tp_active;; activepp = &activep->tpa_next) {
+		activep = *activepp;
+		if (activep->tpa_tid == my_tid) {
+			*activepp = activep->tpa_next;
+			break;
+		}
+	}
+	if (tpool->tp_flags & TP_WAIT)
+		notify_waiters(tpool);
+}
+
+static void *
+tpool_worker(void *arg)
+{
+	tpool_t *tpool = (tpool_t *)arg;
+	int elapsed;
+	tpool_job_t *job;
+	void (*func)(void *);
+	tpool_active_t active;
+	sigset_t maskset;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	pthread_cleanup_push(worker_cleanup, tpool);
+
+	/*
+	 * This is the worker's main loop.
+	 * It will only be left if a timeout or an error has occured.
+	 */
+	active.tpa_tid = pthread_self();
+	for (;;) {
+		elapsed = 0;
+		tpool->tp_idle++;
+		if (tpool->tp_flags & TP_WAIT)
+			notify_waiters(tpool);
+		while ((tpool->tp_head == NULL ||
+		    (tpool->tp_flags & TP_SUSPEND)) &&
+		    !(tpool->tp_flags & (TP_DESTROY | TP_ABANDON))) {
+			if (tpool->tp_current <= tpool->tp_minimum ||
+			    tpool->tp_linger == 0) {
+				(void) pthread_cond_wait(&tpool->tp_workcv,
+				    &tpool->tp_mutex);
+			} else {
+				struct timespec timeout;
+
+				clock_gettime(CLOCK_MONOTONIC, &timeout);
+				timeout.tv_sec += tpool->tp_linger;
+				if (pthread_cond_timedwait(&tpool->tp_workcv,
+				    &tpool->tp_mutex, &timeout) != 0) {
+					elapsed = 1;
+					break;
+				}
+			}
+		}
+		tpool->tp_idle--;
+		if (tpool->tp_flags & TP_DESTROY)
+			break;
+		if (tpool->tp_flags & TP_ABANDON) {
+			/* can't abandon a suspended pool */
+			if (tpool->tp_flags & TP_SUSPEND) {
+				tpool->tp_flags &= ~TP_SUSPEND;
+				(void) pthread_cond_broadcast(&tpool->tp_workcv);
+			}
+			if (tpool->tp_head == NULL)
+				break;
+		}
+		if ((job = tpool->tp_head) != NULL &&
+		    !(tpool->tp_flags & TP_SUSPEND)) {
+			elapsed = 0;
+			func = job->tpj_func;
+			arg = job->tpj_arg;
+			tpool->tp_head = job->tpj_next;
+			if (job == tpool->tp_tail)
+				tpool->tp_tail = NULL;
+			tpool->tp_njobs--;
+			active.tpa_next = tpool->tp_active;
+			tpool->tp_active = &active;
+			pthread_mutex_unlock(&tpool->tp_mutex);
+			pthread_cleanup_push(job_cleanup, tpool);
+			free(job);
+			/*
+			 * Call the specified function.
+			 */
+			func(arg);
+			/*
+			 * We don't know what this thread has been doing,
+			 * so we reset its signal mask and cancellation
+			 * state back to the initial values.
+			 */
+			sigfillset(&maskset);
+			(void) pthread_sigmask(SIG_SETMASK, &maskset, NULL);
+			(void) pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED,
+			    NULL);
+			(void) pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,
+			    NULL);
+			pthread_cleanup_pop(1);
+		}
+		if (elapsed && tpool->tp_current > tpool->tp_minimum) {
+			/*
+			 * We timed out and there is no work to be done
+			 * and the number of workers exceeds the minimum.
+			 * Exit now to reduce the size of the pool.
+			 */
+			break;
+		}
+	}
+	pthread_cleanup_pop(1);
+	return (arg);
+}
+
+/*
+ * Create a worker thread, with all signals blocked.
+ */
+static int
+create_worker(tpool_t *tpool)
+{
+	sigset_t maskset, oset;
+	pthread_t thread;
+	int error;
+
+	sigfillset(&maskset);
+	(void) pthread_sigmask(SIG_SETMASK, &maskset, &oset);
+	error = pthread_create(&thread, &tpool->tp_attr, tpool_worker, tpool);
+	(void) pthread_sigmask(SIG_SETMASK, &oset, NULL);
+	return (error);
+}
+
+tpool_t	*
+tpool_create(uint_t min_threads, uint_t max_threads, uint_t linger,
+	pthread_attr_t *attr)
+{
+	tpool_t	*tpool;
+	int error;
+
+	if (min_threads > max_threads || max_threads < 1) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	tpool = malloc(sizeof (*tpool));
+	if (tpool == NULL) {
+		errno = ENOMEM;
+		return (NULL);
+	}
+	bzero(tpool, sizeof(*tpool));
+	(void) pthread_mutex_init(&tpool->tp_mutex, NULL);
+	(void) pthread_cond_init(&tpool->tp_busycv, NULL);
+	(void) pthread_cond_init(&tpool->tp_workcv, NULL);
+	(void) pthread_cond_init(&tpool->tp_waitcv, NULL);
+	tpool->tp_minimum = min_threads;
+	tpool->tp_maximum = max_threads;
+	tpool->tp_linger = linger;
+
+	/* make all pool threads be detached daemon threads */
+	(void) pthread_attr_init(&tpool->tp_attr);
+	(void) pthread_attr_setdetachstate(&tpool->tp_attr,
+	    PTHREAD_CREATE_DETACHED);
+
+	return (tpool);
+}
+
+/*
+ * Dispatch a work request to the thread pool.
+ * If there are idle workers, awaken one.
+ * Else, if the maximum number of workers has
+ * not been reached, spawn a new worker thread.
+ * Else just return with the job added to the queue.
+ */
+int
+tpool_dispatch(tpool_t *tpool, void (*func)(void *), void *arg)
+{
+	tpool_job_t *job;
+
+	if ((job = malloc(sizeof (*job))) == NULL)
+		return (-1);
+	bzero(job, sizeof(*job));
+	job->tpj_next = NULL;
+	job->tpj_func = func;
+	job->tpj_arg = arg;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+
+	if (tpool->tp_head == NULL)
+		tpool->tp_head = job;
+	else
+		tpool->tp_tail->tpj_next = job;
+	tpool->tp_tail = job;
+	tpool->tp_njobs++;
+
+	if (!(tpool->tp_flags & TP_SUSPEND)) {
+		if (tpool->tp_idle > 0)
+			(void) pthread_cond_signal(&tpool->tp_workcv);
+		else if (tpool->tp_current < tpool->tp_maximum &&
+		    create_worker(tpool) == 0)
+			tpool->tp_current++;
+	}
+
+	pthread_mutex_unlock(&tpool->tp_mutex);
+	return (0);
+}
+
+/*
+ * Assumes: by the time tpool_destroy() is called no one will use this
+ * thread pool in any way and no one will try to dispatch entries to it.
+ * Calling tpool_destroy() from a job in the pool will cause deadlock.
+ */
+void
+tpool_destroy(tpool_t *tpool)
+{
+	tpool_active_t *activep;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	pthread_cleanup_push((_Voidfp)pthread_mutex_unlock, &tpool->tp_mutex);
+
+	/* mark the pool as being destroyed; wakeup idle workers */
+	tpool->tp_flags |= TP_DESTROY;
+	tpool->tp_flags &= ~TP_SUSPEND;
+	(void) pthread_cond_broadcast(&tpool->tp_workcv);
+
+	/* cancel all active workers */
+	for (activep = tpool->tp_active; activep; activep = activep->tpa_next)
+		(void) pthread_cancel(activep->tpa_tid);
+
+	/* wait for all active workers to finish */
+	while (tpool->tp_active != NULL) {
+		tpool->tp_flags |= TP_WAIT;
+		(void) pthread_cond_wait(&tpool->tp_waitcv, &tpool->tp_mutex);
+	}
+
+	/* the last worker to terminate will wake us up */
+	while (tpool->tp_current != 0)
+		(void) pthread_cond_wait(&tpool->tp_busycv, &tpool->tp_mutex);
+
+	pthread_cleanup_pop(1);	/* pthread_mutex_unlock(&tpool->tp_mutex); */
+	delete_pool(tpool);
+}
+
+/*
+ * Like tpool_destroy(), but don't cancel workers or wait for them to finish.
+ * The last worker to terminate will delete the pool.
+ */
+void
+tpool_abandon(tpool_t *tpool)
+{
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	if (tpool->tp_current == 0) {
+		/* no workers, just delete the pool */
+		pthread_mutex_unlock(&tpool->tp_mutex);
+		delete_pool(tpool);
+	} else {
+		/* wake up all workers, last one will delete the pool */
+		tpool->tp_flags |= TP_ABANDON;
+		tpool->tp_flags &= ~TP_SUSPEND;
+		(void) pthread_cond_broadcast(&tpool->tp_workcv);
+		pthread_mutex_unlock(&tpool->tp_mutex);
+	}
+}
+
+/*
+ * Wait for all jobs to complete.
+ * Calling tpool_wait() from a job in the pool will cause deadlock.
+ */
+void
+tpool_wait(tpool_t *tpool)
+{
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	pthread_cleanup_push((_Voidfp)pthread_mutex_unlock, &tpool->tp_mutex);
+	while (tpool->tp_head != NULL || tpool->tp_active != NULL) {
+		tpool->tp_flags |= TP_WAIT;
+		(void) pthread_cond_wait(&tpool->tp_waitcv, &tpool->tp_mutex);
+	}
+	pthread_cleanup_pop(1);	/* pthread_mutex_unlock(&tpool->tp_mutex); */
+}
+
+void
+tpool_suspend(tpool_t *tpool)
+{
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	tpool->tp_flags |= TP_SUSPEND;
+	pthread_mutex_unlock(&tpool->tp_mutex);
+}
+
+int
+tpool_suspended(tpool_t *tpool)
+{
+	int suspended;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	suspended = (tpool->tp_flags & TP_SUSPEND) != 0;
+	pthread_mutex_unlock(&tpool->tp_mutex);
+
+	return (suspended);
+}
+
+void
+tpool_resume(tpool_t *tpool)
+{
+	int excess;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	if (!(tpool->tp_flags & TP_SUSPEND)) {
+		pthread_mutex_unlock(&tpool->tp_mutex);
+		return;
+	}
+	tpool->tp_flags &= ~TP_SUSPEND;
+	(void) pthread_cond_broadcast(&tpool->tp_workcv);
+	excess = tpool->tp_njobs - tpool->tp_idle;
+	while (excess-- > 0 && tpool->tp_current < tpool->tp_maximum) {
+		if (create_worker(tpool) != 0)
+			break;		/* pthread_create() failed */
+		tpool->tp_current++;
+	}
+	pthread_mutex_unlock(&tpool->tp_mutex);
+}
+
+int
+tpool_member(tpool_t *tpool)
+{
+	pthread_t my_tid = pthread_self();
+	tpool_active_t *activep;
+
+	pthread_mutex_lock(&tpool->tp_mutex);
+	for (activep = tpool->tp_active; activep; activep = activep->tpa_next) {
+		if (activep->tpa_tid == my_tid) {
+			pthread_mutex_unlock(&tpool->tp_mutex);
+			return (1);
+		}
+	}
+	pthread_mutex_unlock(&tpool->tp_mutex);
+	return (0);
+}