X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=libraries%2Flibldap_r%2Ftpool.c;h=e23f9ad09cf8b252c31e89308af11490431b2a41;hb=78a9d66e53923e399978e8af066e3f085ca39b53;hp=421fc624a31855ba08d51eb350ffa580e1c672cc;hpb=da00e5dac1825be1340a43da5d0fd5400fc91f43;p=openldap

diff --git a/libraries/libldap_r/tpool.c b/libraries/libldap_r/tpool.c
index 421fc624a3..e23f9ad09c 100644
--- a/libraries/libldap_r/tpool.c
+++ b/libraries/libldap_r/tpool.c
@@ -1,12 +1,16 @@
 /* $OpenLDAP$ */
-/*
- * Copyright 1998-2000 The OpenLDAP Foundation, Redwood City, California, USA
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2006 The OpenLDAP Foundation.
  * All rights reserved.
  *
- * Redistribution and use in source and binary forms are permitted only
- * as authorized by the OpenLDAP Public License.  A copy of this
- * license is available at http://www.OpenLDAP.org/license.html or
- * in file LICENSE in the top-level directory of the distribution.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
  */
 
 #include "portable.h"
@@ -17,25 +21,50 @@
 #include <ac/stdlib.h>
 #include <ac/string.h>
 #include <ac/time.h>
+#include <ac/errno.h>
 
 #include "ldap-int.h"
-#include "ldap_pvt_thread.h"
+#include "ldap_pvt_thread.h" /* Get the thread interface */
 #include "ldap_queue.h"
+#define LDAP_THREAD_POOL_IMPLEMENTATION
+#include "ldap_thr_debug.h"  /* May rename symbols defined below */
 
 #ifndef LDAP_THREAD_HAVE_TPOOL
 
-enum ldap_int_thread_pool_state {
+typedef enum ldap_int_thread_pool_state_e {
 	LDAP_INT_THREAD_POOL_RUNNING,
 	LDAP_INT_THREAD_POOL_FINISHING,
-	LDAP_INT_THREAD_POOL_STOPPING
-};
+	LDAP_INT_THREAD_POOL_STOPPING,
+	LDAP_INT_THREAD_POOL_PAUSING
+} ldap_int_thread_pool_state_t;
+
+typedef struct ldap_int_thread_key_s {
+	void *ltk_key;
+	void *ltk_data;
+	ldap_pvt_thread_pool_keyfree_t *ltk_free;
+} ldap_int_thread_key_t;
+
+/* Max number of thread-specific keys we store per thread.
+ * We don't expect to use many...
+ */
+#define	MAXKEYS	32
+#define	LDAP_MAXTHR	1024	/* must be a power of 2 */
+
+static ldap_pvt_thread_t tid_zero;
+
+static struct {
+	ldap_pvt_thread_t id;
+	ldap_int_thread_key_t *ctx;
+} thread_keys[LDAP_MAXTHR];
+	
 
 typedef struct ldap_int_thread_ctx_s {
 	union {
 	LDAP_STAILQ_ENTRY(ldap_int_thread_ctx_s) q;
 	LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) l;
+	LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) al;
 	} ltc_next;
-	void *(*ltc_start_routine)( void *);
+	ldap_pvt_thread_start_t *ltc_start_routine;
 	void *ltc_arg;
 } ldap_int_thread_ctx_t;
 
@@ -43,9 +72,11 @@ struct ldap_int_thread_pool_s {
 	LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
 	ldap_pvt_thread_mutex_t ltp_mutex;
 	ldap_pvt_thread_cond_t ltp_cond;
+	ldap_pvt_thread_cond_t ltp_pcond;
 	LDAP_STAILQ_HEAD(tcq, ldap_int_thread_ctx_s) ltp_pending_list;
 	LDAP_SLIST_HEAD(tcl, ldap_int_thread_ctx_s) ltp_free_list;
-	long ltp_state;
+	LDAP_SLIST_HEAD(tclq, ldap_int_thread_ctx_s) ltp_active_list;
+	ldap_int_thread_pool_state_t ltp_state;
 	long ltp_max_count;
 	long ltp_max_pending;
 	long ltp_pending_count;
@@ -60,12 +91,17 @@ static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s)
 
 static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex;
 
-static void *ldap_int_thread_pool_wrapper(
-	struct ldap_int_thread_pool_s *pool );
+static void *ldap_int_thread_pool_wrapper( void *pool );
+
+static ldap_pvt_thread_t ldap_int_main_tid;
+
+static ldap_int_thread_key_t ldap_int_main_thrctx[LDAP_MAXTHR];
 
 int
 ldap_int_thread_pool_startup ( void )
 {
+	ldap_int_main_tid = ldap_pvt_thread_self();
+
 	return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex);
 }
 
@@ -76,12 +112,137 @@ ldap_int_thread_pool_shutdown ( void )
 
 	while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) {
 		LDAP_STAILQ_REMOVE_HEAD(&ldap_int_thread_pool_list, ltp_next);
-		ldap_pvt_thread_pool_destroy( &pool, 0);
+		(ldap_pvt_thread_pool_destroy)(&pool, 0); /* ignore thr_debug macro */
 	}
 	ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex);
 	return(0);
 }
 
+typedef struct ldap_lazy_sem_t {
+	ldap_pvt_thread_mutex_t ls_mutex;
+	ldap_pvt_thread_cond_t	ls_cond;
+	int ls_sem_value;
+	/*
+	 * when more than ls_lazy_count number of resources
+	 * becmoes available, the thread wating for the resources will
+	 * be waken up in order to prevent frequent blocking/waking-up
+	 */
+	unsigned int ls_lazy_count;
+	/*
+	 * only one thread(listener) will wait on this semaphore
+	 * using a flag instead of a list
+	 */
+	int ls_wait;
+} ldap_lazy_sem_t;
+
+ldap_lazy_sem_t* thread_pool_sem = NULL;
+
+int
+ldap_lazy_sem_init( unsigned int value, unsigned int lazyness )
+{
+	thread_pool_sem = (ldap_lazy_sem_t*) LDAP_CALLOC(1,
+		sizeof( ldap_lazy_sem_t ));
+
+	if( thread_pool_sem == NULL ) return -1;
+
+	ldap_pvt_thread_mutex_init( &thread_pool_sem->ls_mutex );
+	ldap_pvt_thread_cond_init( &thread_pool_sem->ls_cond );
+	thread_pool_sem->ls_sem_value = value;
+	thread_pool_sem->ls_lazy_count = lazyness;
+	thread_pool_sem->ls_wait = 0;
+
+	return 0;
+}
+
+/* FIXME: move to some approprite header */
+int ldap_lazy_sem_dec( ldap_lazy_sem_t* ls );
+int ldap_lazy_sem_wait ( ldap_lazy_sem_t* ls );
+
+/*
+ * ldap_lazy_sem_wait is used if a caller is blockable(listener).
+ * Otherwise use ldap_lazy_sem_dec (worker)
+ */
+int
+ldap_lazy_sem_op_submit( ldap_lazy_sem_t* ls )
+{
+	if ( ls == NULL ) return -1;
+
+	/* only worker thread has its thread ctx */
+	if ( ldap_pvt_thread_pool_context() ) {
+		/* worker thread */
+		return ldap_lazy_sem_dec( ls );
+	} else {
+		/* listener */
+		return ldap_lazy_sem_wait( ls );
+	}
+}
+
+/*
+ * test if given semaphore's count is zero.
+ * If 0, the caller is blocked 
+ * If not, the count is decremented.
+ */
+int
+ldap_lazy_sem_wait ( ldap_lazy_sem_t* ls )
+{
+	ldap_pvt_thread_mutex_lock( &ls->ls_mutex );
+
+lazy_sem_retry:
+	if ( ls->ls_sem_value <= 0 ) {
+		/* no more avaliable resources */
+		ls->ls_wait = 1;
+		ldap_pvt_thread_cond_wait( &ls->ls_cond, &ls->ls_mutex );
+		goto lazy_sem_retry;
+	} else {
+		/* avaliable resources */
+		ls->ls_sem_value--;
+	}
+
+	ldap_pvt_thread_mutex_unlock( &ls->ls_mutex );
+
+	return 0;
+}
+
+/*
+ * decrement the count without blocking
+ * even when the count becomes less than or equal to 0
+ */
+int
+ldap_lazy_sem_dec( ldap_lazy_sem_t* ls )
+{
+	ldap_pvt_thread_mutex_lock( &ls->ls_mutex );
+
+	ls->ls_sem_value--;
+
+	ldap_pvt_thread_mutex_unlock( &ls->ls_mutex );
+
+	return 0;
+}
+
+/*
+ * Increment the count by one and test if it is greater or
+ * equal to lazyness. If it is, wake up a blocked thread.
+ */
+int
+ldap_lazy_sem_post( ldap_lazy_sem_t* ls )
+{
+	if( ls == NULL ) return (-1);
+
+	ldap_pvt_thread_mutex_lock( &ls->ls_mutex );
+
+	ls->ls_sem_value++;
+	if ( ls->ls_wait ) {
+		if ( ls->ls_sem_value >= ls->ls_lazy_count ) {
+			ls->ls_wait = 0;
+			ldap_pvt_thread_cond_signal( &ls->ls_cond );
+		}
+	}
+
+	ldap_pvt_thread_mutex_unlock( &ls->ls_mutex );
+
+	return 0;
+}
+
 int
 ldap_pvt_thread_pool_init (
 	ldap_pvt_thread_pool_t *tpool,
@@ -101,6 +262,9 @@ ldap_pvt_thread_pool_init (
 	if (rc != 0)
 		return(rc);
 	rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
+	if (rc != 0)
+		return(rc);
+	rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
 	if (rc != 0)
 		return(rc);
 	pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
@@ -108,6 +272,7 @@ ldap_pvt_thread_pool_init (
 	pool->ltp_max_pending = max_pending;
 	LDAP_STAILQ_INIT(&pool->ltp_pending_list);
 	LDAP_SLIST_INIT(&pool->ltp_free_list);
+	LDAP_SLIST_INIT(&pool->ltp_active_list);
 	ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 	LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next);
 	ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
@@ -130,8 +295,7 @@ ldap_pvt_thread_pool_init (
 	pool->ltp_open_count++;
 
 	ldap_pvt_thread_t thr;
-	rc = ldap_pvt_thread_create( &thr, 1,
-		(void *) ldap_int_thread_pool_wrapper, pool );
+	rc = ldap_pvt_thread_create( &thr, 1, ldap_int_thread_pool_wrapper, pool );
 
 	if( rc != 0) {
 		/* couldn't start one?  then don't start any */
@@ -139,6 +303,7 @@ ldap_pvt_thread_pool_init (
 		LDAP_STAILQ_REMOVE(ldap_int_thread_pool_list, pool, 
 			ldap_int_thread_pool_s, ltp_next);
 		ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
+		ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 		ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 		ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 		LDAP_FREE(pool);
@@ -150,10 +315,14 @@ ldap_pvt_thread_pool_init (
 	return(0);
 }
 
+#define	TID_HASH(tid, hash) do { unsigned i; \
+	unsigned char *ptr = (unsigned char *)&(tid); \
+	for (i=0, hash=0; i<sizeof(tid); i++) hash += ptr[i]; } while(0)
+
 int
 ldap_pvt_thread_pool_submit (
 	ldap_pvt_thread_pool_t *tpool,
-	void *(*start_routine)( void * ), void *arg )
+	ldap_pvt_thread_start_t *start_routine, void *arg )
 {
 	struct ldap_int_thread_pool_s *pool;
 	ldap_int_thread_ctx_t *ctx;
@@ -169,7 +338,8 @@ ldap_pvt_thread_pool_submit (
 		return(-1);
 
 	ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
-	if (pool->ltp_state != LDAP_INT_THREAD_POOL_RUNNING
+	if ((pool->ltp_state != LDAP_INT_THREAD_POOL_RUNNING &&
+		pool->ltp_state != LDAP_INT_THREAD_POOL_PAUSING)
 		|| (pool->ltp_max_pending > 0
 			&& pool->ltp_pending_count >= pool->ltp_max_pending))
 	{
@@ -193,12 +363,14 @@ ldap_pvt_thread_pool_submit (
 
 	pool->ltp_pending_count++;
 	LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, ctx, ltc_next.q);
+	if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
+		ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+		return(0);
+	}
 	ldap_pvt_thread_cond_signal(&pool->ltp_cond);
-	if ((pool->ltp_open_count <= 0
-			|| pool->ltp_pending_count > 1
-			|| pool->ltp_open_count == pool->ltp_active_count)
-		&& (pool->ltp_max_count <= 0
-			|| pool->ltp_open_count < pool->ltp_max_count))
+	if (pool->ltp_open_count < pool->ltp_active_count + pool->ltp_pending_count
+		&& (pool->ltp_open_count < pool->ltp_max_count ||
+			pool->ltp_max_count <= 0 ))
 	{
 		pool->ltp_open_count++;
 		pool->ltp_starting++;
@@ -206,12 +378,30 @@ ldap_pvt_thread_pool_submit (
 	}
 	ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 
+#ifdef LDAP_PVT_THREAD_POOL_SEM_LOAD_CONTROL
+	ldap_lazy_sem_op_submit( thread_pool_sem );
+#endif
+
 	if (need_thread) {
-		int rc = ldap_pvt_thread_create( &thr, 1,
-			(void *)ldap_int_thread_pool_wrapper, pool );
+		int rc;
+
 		ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+		rc = ldap_pvt_thread_create( &thr, 1,
+			ldap_int_thread_pool_wrapper, pool );
 		if (rc == 0) {
+			int hash;
 			pool->ltp_starting--;
+
+			/* assign this thread ID to a key slot; start
+			 * at the thread ID itself (mod LDAP_MAXTHR) and
+			 * look for an empty slot.
+			 */
+			TID_HASH(thr, hash);
+			for (rc = hash & (LDAP_MAXTHR-1);
+				!ldap_pvt_thread_equal(thread_keys[rc].id, tid_zero);
+				rc = (rc+1) & (LDAP_MAXTHR-1));
+			thread_keys[rc].id = thr;
 		} else {
 			/* couldn't create thread.  back out of
 			 * ltp_open_count and check for even worse things.
@@ -316,14 +506,8 @@ ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 	pool->ltp_state = run_pending
 		? LDAP_INT_THREAD_POOL_FINISHING
 		: LDAP_INT_THREAD_POOL_STOPPING;
-	waiting = pool->ltp_open_count;
 
-	/* broadcast could be used here, but only after
-	 * it is fixed in the NT thread implementation
-	 */
-	while (--waiting >= 0) {
-		ldap_pvt_thread_cond_signal(&pool->ltp_cond);
-	}
+	ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 	ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 
 	do {
@@ -345,23 +529,47 @@ ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 		LDAP_FREE(ctx);
 	}
 
+	ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 	ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 	ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 	LDAP_FREE(pool);
+#ifdef LDAP_PVT_THREAD_POOL_SEM_LOAD_CONTROL
+	if ( thread_pool_sem ) {
+		LDAP_FREE( thread_pool_sem );
+	}
+#endif
 	return(0);
 }
 
 static void *
 ldap_int_thread_pool_wrapper ( 
-	struct ldap_int_thread_pool_s *pool )
+	void *xpool )
 {
+	struct ldap_int_thread_pool_s *pool = xpool;
 	ldap_int_thread_ctx_t *ctx;
+	ldap_int_thread_key_t ltc_key[MAXKEYS];
+	ldap_pvt_thread_t tid;
+	int i, keyslot, hash;
 
 	if (pool == NULL)
 		return NULL;
 
+	for ( i=0; i<MAXKEYS; i++ ) {
+		ltc_key[i].ltk_key = NULL;
+	}
+
+	tid = ldap_pvt_thread_self();
+
 	ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 
+	/* store pointer to our keys */
+	TID_HASH(tid, hash);
+	for (i = hash & (LDAP_MAXTHR-1);
+				!ldap_pvt_thread_equal(thread_keys[i].id, tid);
+				i = (i+1) & (LDAP_MAXTHR-1));
+	thread_keys[i].ctx = ltc_key;
+	keyslot = i;
+
 	while (pool->ltp_state != LDAP_INT_THREAD_POOL_STOPPING) {
 		ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
 		if (ctx) {
@@ -387,34 +595,218 @@ ldap_int_thread_pool_wrapper (
 			 * should be like this:
 			 *   if (pool->ltp_open_count > 1 && pool->ltp_starting == 0)
 			 *       check timer, leave thread (break;)
+			 *
+			 * Just use pthread_cond_timedwait if we want to
+			 * check idle time.
 			 */
 
-			if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING)
+			if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING
+				|| pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING)
+			{
 				ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+			}
 
 			continue;
 		}
 
 		pool->ltp_pending_count--;
+
+		LDAP_SLIST_INSERT_HEAD(&pool->ltp_active_list, ctx, ltc_next.al);
 		pool->ltp_active_count++;
 		ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 
-		(ctx->ltc_start_routine)(ctx->ltc_arg);
-		LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, ctx, ltc_next.l);
-		ldap_pvt_thread_yield();
-
-		/* if we use an idle timer, here's
-		 * a good place to update it
-		 */
+		ctx->ltc_start_routine(ltc_key, ctx->ltc_arg);
 
+#ifdef LDAP_PVT_THREAD_POOL_SEM_LOAD_CONTROL
+		ldap_lazy_sem_post( thread_pool_sem );
+#endif
 		ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+		LDAP_SLIST_REMOVE(&pool->ltp_active_list, ctx,
+			ldap_int_thread_ctx_s, ltc_next.al);
+		LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, ctx, ltc_next.l);
 		pool->ltp_active_count--;
+
+		if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
+			if (pool->ltp_active_count < 2) {
+				ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
+			}
+			ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+		}
 	}
 
+	for ( i=0; i<MAXKEYS && ltc_key[i].ltk_key; i++ ) {
+		if (ltc_key[i].ltk_free)
+			ltc_key[i].ltk_free(
+				ltc_key[i].ltk_key,
+				ltc_key[i].ltk_data );
+	}
+
+	thread_keys[keyslot].ctx = NULL;
+	thread_keys[keyslot].id = tid_zero;
+
 	pool->ltp_open_count--;
 	ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 
 	ldap_pvt_thread_exit(NULL);
 	return(NULL);
 }
-#endif /* LDAP_HAVE_THREAD_POOL */
+
+int
+ldap_pvt_thread_pool_pause ( 
+	ldap_pvt_thread_pool_t *tpool )
+{
+	struct ldap_int_thread_pool_s *pool;
+
+	if (tpool == NULL)
+		return(-1);
+
+	pool = *tpool;
+
+	if (pool == NULL)
+		return(0);
+
+	ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+	/* If someone else has already requested a pause, we have to wait */
+	while (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
+		pool->ltp_pending_count++;
+		pool->ltp_active_count--;
+		ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+		pool->ltp_pending_count--;
+		pool->ltp_active_count++;
+	}
+	/* Wait for everyone else to finish */
+	pool->ltp_state = LDAP_INT_THREAD_POOL_PAUSING;
+	while (pool->ltp_active_count > 1) {
+		ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
+	}
+	ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+	return(0);
+}
+
+int
+ldap_pvt_thread_pool_resume ( 
+	ldap_pvt_thread_pool_t *tpool )
+{
+	struct ldap_int_thread_pool_s *pool;
+
+	if (tpool == NULL)
+		return(-1);
+
+	pool = *tpool;
+
+	if (pool == NULL)
+		return(0);
+
+	ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+	pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
+	ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
+	ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+	return(0);
+}
+
+int ldap_pvt_thread_pool_getkey(
+	void *xctx,
+	void *key,
+	void **data,
+	ldap_pvt_thread_pool_keyfree_t **kfree )
+{
+	ldap_int_thread_key_t *ctx = xctx;
+	int i;
+
+	if ( !ctx || !data ) return EINVAL;
+
+	for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++ ) {
+		if ( ctx[i].ltk_key == key ) {
+			*data = ctx[i].ltk_data;
+			if ( kfree ) *kfree = ctx[i].ltk_free;
+			return 0;
+		}
+	}
+	return ENOENT;
+}
+
+int ldap_pvt_thread_pool_setkey(
+	void *xctx,
+	void *key,
+	void *data,
+	ldap_pvt_thread_pool_keyfree_t *kfree )
+{
+	ldap_int_thread_key_t *ctx = xctx;
+	int i;
+
+	if ( !ctx || !key ) return EINVAL;
+
+	for ( i=0; i<MAXKEYS; i++ ) {
+		if ( !ctx[i].ltk_key || ctx[i].ltk_key == key ) {
+			ctx[i].ltk_key = key;
+			ctx[i].ltk_data = data;
+			ctx[i].ltk_free = kfree;
+			return 0;
+		}
+	}
+	return ENOMEM;
+}
+
+/* Free all elements with this key, no matter which thread they're in.
+ * May only be called while the pool is paused.
+ */
+void ldap_pvt_thread_pool_purgekey( void *key )
+{
+	int i, j;
+	ldap_int_thread_key_t *ctx;
+
+	for ( i=0; i<LDAP_MAXTHR; i++ ) {
+		if ( thread_keys[i].ctx ) {
+			ctx = thread_keys[i].ctx;
+			for ( j=0; j<MAXKEYS; j++ ) {
+				if ( ctx[j].ltk_key == key ) {
+					if (ctx[j].ltk_free)
+						ctx[j].ltk_free( ctx[j].ltk_key, ctx[j].ltk_data );
+					ctx[j].ltk_key = NULL;
+					ctx[j].ltk_free = NULL;
+					break;
+				}
+			}
+		}
+	}
+}
+
+/*
+ * This is necessary if the caller does not have access to the
+ * thread context handle (for example, a slapd plugin calling
+ * slapi_search_internal()). No doubt it is more efficient to
+ * for the application to keep track of the thread context
+ * handles itself.
+ */
+void *ldap_pvt_thread_pool_context( )
+{
+	ldap_pvt_thread_t tid;
+	int i, hash;
+
+	tid = ldap_pvt_thread_self();
+	if ( ldap_pvt_thread_equal( tid, ldap_int_main_tid ))
+		return ldap_int_main_thrctx;
+
+	TID_HASH( tid, hash );
+	for (i = hash & (LDAP_MAXTHR-1);
+		!ldap_pvt_thread_equal(thread_keys[i].id, tid_zero) &&
+		!ldap_pvt_thread_equal(thread_keys[i].id, tid);
+		i = (i+1) & (LDAP_MAXTHR-1));
+
+	return thread_keys[i].ctx;
+}
+
+void ldap_pvt_thread_pool_context_reset( void *vctx )
+{
+	ldap_int_thread_key_t *ctx = vctx;
+	int i;
+
+	for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++) {
+		if ( ctx[i].ltk_free )
+			ctx[i].ltk_free( ctx[i].ltk_key, ctx[i].ltk_data );
+		ctx[i].ltk_key = NULL;
+	}
+}
+#endif /* LDAP_THREAD_HAVE_TPOOL */