lib/dynamicsizehash_concurrent.c - platform/external/elfutils.git - Git at Google

 /* Copyright (C) 2000-2019 Red Hat, Inc.
    This file is part of elfutils.
    Written by Srdan Milakovic <sm108@rice.edu>, 2019.
    Derived from Ulrich Drepper <drepper@redhat.com>, 2000.

    This file is free software; you can redistribute it and/or modify
    it under the terms of either

      * 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

    or

      * the GNU General Public License as published by the Free
        Software Foundation; either version 2 of the License, or (at
        your option) any later version

    or both in parallel, as here.

    elfutils 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 copies of the GNU General Public License and
    the GNU Lesser General Public License along with this program.  If
    not, see <http://www.gnu.org/licenses/>.  */

 #include <assert.h>
 #include <stdlib.h>
 #include <system.h>
 #include <pthread.h>

 /* Before including this file the following macros must be defined:

    NAME      name of the hash table structure.
    TYPE      data type of the hash table entries
  */


 static size_t
 lookup (NAME *htab, HASHTYPE hval)
 {
   /* First hash function: simply take the modul but prevent zero.  Small values
       can skip the division, which helps performance when this is common.  */
   size_t idx = 1 + (hval < htab->size ? hval : hval % htab->size);

   HASHTYPE hash;

   hash = atomic_load_explicit(&htab->table[idx].hashval,
                               memory_order_acquire);
   if (hash == hval)
     return idx;
   else if (hash == 0)
     return 0;

   /* Second hash function as suggested in [Knuth].  */
   HASHTYPE second_hash = 1 + hval % (htab->size - 2);

   for(;;)
     {
       if (idx <= second_hash)
           idx = htab->size + idx - second_hash;
       else
           idx -= second_hash;

       hash = atomic_load_explicit(&htab->table[idx].hashval,
                                   memory_order_acquire);
       if (hash == hval)
 	return idx;
       else if (hash == 0)
 	return 0;
     }
 }

 static int
 insert_helper (NAME *htab, HASHTYPE hval, TYPE val)
 {
   /* First hash function: simply take the modul but prevent zero.  Small values
       can skip the division, which helps performance when this is common.  */
   size_t idx = 1 + (hval < htab->size ? hval : hval % htab->size);

   TYPE val_ptr;
   HASHTYPE hash;

   hash = atomic_load_explicit(&htab->table[idx].hashval,
                               memory_order_acquire);
   if (hash == hval)
     return -1;
   else if (hash == 0)
     {
       val_ptr = NULL;
       atomic_compare_exchange_strong_explicit(&htab->table[idx].val_ptr,
                                               (uintptr_t *) &val_ptr,
                                               (uintptr_t) val,
                                               memory_order_acquire,
                                               memory_order_acquire);

       if (val_ptr == NULL)
         {
           atomic_store_explicit(&htab->table[idx].hashval, hval,
                                 memory_order_release);
           return 0;
         }
       else
         {
           do
             {
               hash = atomic_load_explicit(&htab->table[idx].hashval,
                                           memory_order_acquire);
             }
           while (hash == 0);
           if (hash == hval)
             return -1;
         }
     }

   /* Second hash function as suggested in [Knuth].  */
   HASHTYPE second_hash = 1 + hval % (htab->size - 2);

   for(;;)
     {
       if (idx <= second_hash)
           idx = htab->size + idx - second_hash;
       else
           idx -= second_hash;

       hash = atomic_load_explicit(&htab->table[idx].hashval,
                                   memory_order_acquire);
       if (hash == hval)
         return -1;
       else if (hash == 0)
         {
           val_ptr = NULL;
           atomic_compare_exchange_strong_explicit(&htab->table[idx].val_ptr,
                                                   (uintptr_t *) &val_ptr,
                                                   (uintptr_t) val,
                                                   memory_order_acquire,
                                                   memory_order_acquire);

           if (val_ptr == NULL)
             {
               atomic_store_explicit(&htab->table[idx].hashval, hval,
                                     memory_order_release);
               return 0;
             }
           else
             {
               do
                 {
                   hash = atomic_load_explicit(&htab->table[idx].hashval,
                                               memory_order_acquire);
                 }
               while (hash == 0);
               if (hash == hval)
                 return -1;
             }
         }
     }
 }

 #define NO_RESIZING 0u
 #define ALLOCATING_MEMORY 1u
 #define MOVING_DATA 3u
 #define CLEANING 2u

 #define STATE_BITS 2u
 #define STATE_INCREMENT (1u << STATE_BITS)
 #define STATE_MASK (STATE_INCREMENT - 1)
 #define GET_STATE(A) ((A) & STATE_MASK)

 #define IS_NO_RESIZE_OR_CLEANING(A) (((A) & 0x1u) == 0)

 #define GET_ACTIVE_WORKERS(A) ((A) >> STATE_BITS)

 #define INITIALIZATION_BLOCK_SIZE 256
 #define MOVE_BLOCK_SIZE 256
 #define CEIL(A, B) (((A) + (B) - 1) / (B))

 /* Initializes records and copies the data from the old table.
    It can share work with other threads */
 static void resize_helper(NAME *htab, int blocking)
 {
   size_t num_old_blocks = CEIL(htab->old_size, MOVE_BLOCK_SIZE);
   size_t num_new_blocks = CEIL(htab->size, INITIALIZATION_BLOCK_SIZE);

   size_t my_block;
   size_t num_finished_blocks = 0;

   while ((my_block = atomic_fetch_add_explicit(&htab->next_init_block, 1,
                                                 memory_order_acquire))
                                                     < num_new_blocks)
     {
       size_t record_it = my_block * INITIALIZATION_BLOCK_SIZE;
       size_t record_end = (my_block + 1) * INITIALIZATION_BLOCK_SIZE;
       if (record_end > htab->size)
           record_end = htab->size;

       while (record_it++ != record_end)
         {
           atomic_init(&htab->table[record_it].hashval, (uintptr_t) NULL);
           atomic_init(&htab->table[record_it].val_ptr, (uintptr_t) NULL);
         }

       num_finished_blocks++;
     }

   atomic_fetch_add_explicit(&htab->num_initialized_blocks,
                             num_finished_blocks, memory_order_release);
   while (atomic_load_explicit(&htab->num_initialized_blocks,
                               memory_order_acquire) != num_new_blocks);

   /* All block are initialized, start moving */
   num_finished_blocks = 0;
   while ((my_block = atomic_fetch_add_explicit(&htab->next_move_block, 1,
                                                 memory_order_acquire))
                                                     < num_old_blocks)
     {
       size_t record_it = my_block * MOVE_BLOCK_SIZE;
       size_t record_end = (my_block + 1) * MOVE_BLOCK_SIZE;
       if (record_end > htab->old_size)
           record_end = htab->old_size;

       while (record_it++ != record_end)
         {
           TYPE val_ptr = (TYPE) atomic_load_explicit(
               &htab->old_table[record_it].val_ptr,
               memory_order_acquire);
           if (val_ptr == NULL)
               continue;

           HASHTYPE hashval = atomic_load_explicit(
               &htab->old_table[record_it].hashval,
               memory_order_acquire);
           assert(hashval);

           insert_helper(htab, hashval, val_ptr);
         }

       num_finished_blocks++;
     }

   atomic_fetch_add_explicit(&htab->num_moved_blocks, num_finished_blocks,
                             memory_order_release);

   if (blocking)
       while (atomic_load_explicit(&htab->num_moved_blocks,
                                   memory_order_acquire) != num_old_blocks);
 }

 static void
 resize_master(NAME *htab)
 {
   htab->old_size = htab->size;
   htab->old_table = htab->table;

   htab->size = next_prime(htab->size * 2);
   htab->table = malloc((1 + htab->size) * sizeof(htab->table[0]));
   assert(htab->table);

   /* Change state from ALLOCATING_MEMORY to MOVING_DATA */
   atomic_fetch_xor_explicit(&htab->resizing_state,
                             ALLOCATING_MEMORY ^ MOVING_DATA,
                             memory_order_release);

   resize_helper(htab, 1);

   /* Change state from MOVING_DATA to CLEANING */
   size_t resize_state = atomic_fetch_xor_explicit(&htab->resizing_state,
                                                   MOVING_DATA ^ CLEANING,
                                                   memory_order_acq_rel);
   while (GET_ACTIVE_WORKERS(resize_state) != 0)
       resize_state = atomic_load_explicit(&htab->resizing_state,
                                           memory_order_acquire);

   /* There are no more active workers */
   atomic_store_explicit(&htab->next_init_block, 0, memory_order_relaxed);
   atomic_store_explicit(&htab->num_initialized_blocks, 0,
                         memory_order_relaxed);

   atomic_store_explicit(&htab->next_move_block, 0, memory_order_relaxed);
   atomic_store_explicit(&htab->num_moved_blocks, 0, memory_order_relaxed);

   free(htab->old_table);

   /* Change state to NO_RESIZING */
   atomic_fetch_xor_explicit(&htab->resizing_state, CLEANING ^ NO_RESIZING,
                             memory_order_relaxed);

 }

 static void
 resize_worker(NAME *htab)
 {
   size_t resize_state = atomic_load_explicit(&htab->resizing_state,
                                               memory_order_acquire);

   /* If the resize has finished */
   if (IS_NO_RESIZE_OR_CLEANING(resize_state))
       return;

   /* Register as worker and check if the resize has finished in the meantime*/
   resize_state = atomic_fetch_add_explicit(&htab->resizing_state,
                                             STATE_INCREMENT,
                                             memory_order_acquire);
   if (IS_NO_RESIZE_OR_CLEANING(resize_state))
     {
       atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
                                 memory_order_relaxed);
       return;
     }

   /* Wait while the new table is being allocated. */
   while (GET_STATE(resize_state) == ALLOCATING_MEMORY)
       resize_state = atomic_load_explicit(&htab->resizing_state,
                                           memory_order_acquire);

   /* Check if the resize is done */
   assert(GET_STATE(resize_state) != NO_RESIZING);
   if (GET_STATE(resize_state) == CLEANING)
     {
       atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
                                 memory_order_relaxed);
       return;
     }

   resize_helper(htab, 0);

   /* Deregister worker */
   atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
                             memory_order_release);
 }


 int
 #define INIT(name) _INIT (name)
 #define _INIT(name) \
   name##_init
 INIT(NAME) (NAME *htab, size_t init_size)
 {
   /* We need the size to be a prime.  */
   init_size = next_prime (init_size);

   /* Initialize the data structure.  */
   htab->size = init_size;
   atomic_init(&htab->filled, 0);
   atomic_init(&htab->resizing_state, 0);

   atomic_init(&htab->next_init_block, 0);
   atomic_init(&htab->num_initialized_blocks, 0);

   atomic_init(&htab->next_move_block, 0);
   atomic_init(&htab->num_moved_blocks, 0);

   pthread_rwlock_init(&htab->resize_rwl, NULL);

   htab->table = (void *) malloc ((init_size + 1) * sizeof (htab->table[0]));
   if (htab->table == NULL)
       return -1;

   for (size_t i = 0; i <= init_size; i++)
     {
       atomic_init(&htab->table[i].hashval, (uintptr_t) NULL);
       atomic_init(&htab->table[i].val_ptr, (uintptr_t) NULL);
     }

   return 0;
 }


 int
 #define FREE(name) _FREE (name)
 #define _FREE(name) \
 name##_free
 FREE(NAME) (NAME *htab)
 {
   pthread_rwlock_destroy(&htab->resize_rwl);
   free (htab->table);
   return 0;
 }


 int
 #define INSERT(name) _INSERT (name)
 #define _INSERT(name) \
 name##_insert
 INSERT(NAME) (NAME *htab, HASHTYPE hval, TYPE data)
 {
   int incremented = 0;

   for(;;)
     {
       while (pthread_rwlock_tryrdlock(&htab->resize_rwl) != 0)
           resize_worker(htab);

       size_t filled;
       if (!incremented)
         {
           filled = atomic_fetch_add_explicit(&htab->filled, 1,
                                               memory_order_acquire);
           incremented = 1;
         }
       else
         {
           filled = atomic_load_explicit(&htab->filled,
                                         memory_order_acquire);
         }


       if (100 * filled > 90 * htab->size)
         {
           /* Table is filled more than 90%.  Resize the table.  */

           size_t resizing_state = atomic_load_explicit(&htab->resizing_state,
                                                         memory_order_acquire);
           if (resizing_state == 0 &&
               atomic_compare_exchange_strong_explicit(&htab->resizing_state,
                                                       &resizing_state,
                                                       ALLOCATING_MEMORY,
                                                       memory_order_acquire,
                                                       memory_order_acquire))
             {
               /* Master thread */
               pthread_rwlock_unlock(&htab->resize_rwl);

               pthread_rwlock_wrlock(&htab->resize_rwl);
               resize_master(htab);
               pthread_rwlock_unlock(&htab->resize_rwl);

             }
           else
             {
               /* Worker thread */
               pthread_rwlock_unlock(&htab->resize_rwl);
               resize_worker(htab);
             }
         }
       else
         {
           /* Lock acquired, no need for resize*/
           break;
         }
     }

   int ret_val = insert_helper(htab, hval, data);
   if (ret_val == -1)
       atomic_fetch_sub_explicit(&htab->filled, 1, memory_order_relaxed);
   pthread_rwlock_unlock(&htab->resize_rwl);
   return ret_val;
 }


 TYPE
 #define FIND(name) _FIND (name)
 #define _FIND(name) \
   name##_find
 FIND(NAME) (NAME *htab, HASHTYPE hval)
 {
   while (pthread_rwlock_tryrdlock(&htab->resize_rwl) != 0)
       resize_worker(htab);

   size_t idx;

   /* Make the hash data nonzero.  */
   hval = hval ?: 1;
   idx = lookup(htab, hval);

   if (idx == 0)
     {
       pthread_rwlock_unlock(&htab->resize_rwl);
       return NULL;
     }

   /* get a copy before unlocking the lock */
   TYPE ret_val = (TYPE) atomic_load_explicit(&htab->table[idx].val_ptr,
                                              memory_order_relaxed);

   pthread_rwlock_unlock(&htab->resize_rwl);
   return ret_val;
 }
	/* Copyright (C) 2000-2019 Red Hat, Inc.
	This file is part of elfutils.
	Written by Srdan Milakovic <sm108@rice.edu>, 2019.
	Derived from Ulrich Drepper <drepper@redhat.com>, 2000.

	This file is free software; you can redistribute it and/or modify
	it under the terms of either

	* 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

	or

	* the GNU General Public License as published by the Free
	Software Foundation; either version 2 of the License, or (at
	your option) any later version

	or both in parallel, as here.

	elfutils 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 copies of the GNU General Public License and
	the GNU Lesser General Public License along with this program. If
	not, see <http://www.gnu.org/licenses/>. */

	#include <assert.h>
	#include <stdlib.h>
	#include <system.h>
	#include <pthread.h>

	/* Before including this file the following macros must be defined:

	NAME name of the hash table structure.
	TYPE data type of the hash table entries
	*/


	static size_t
	lookup (NAME *htab, HASHTYPE hval)
	{
	/* First hash function: simply take the modul but prevent zero. Small values
	can skip the division, which helps performance when this is common. */
	size_t idx = 1 + (hval < htab->size ? hval : hval % htab->size);

	HASHTYPE hash;

	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	if (hash == hval)
	return idx;
	else if (hash == 0)
	return 0;

	/* Second hash function as suggested in [Knuth]. */
	HASHTYPE second_hash = 1 + hval % (htab->size - 2);

	for(;;)
	{
	if (idx <= second_hash)
	idx = htab->size + idx - second_hash;
	else
	idx -= second_hash;

	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	if (hash == hval)
	return idx;
	else if (hash == 0)
	return 0;
	}
	}

	static int
	insert_helper (NAME *htab, HASHTYPE hval, TYPE val)
	{
	/* First hash function: simply take the modul but prevent zero. Small values
	can skip the division, which helps performance when this is common. */
	size_t idx = 1 + (hval < htab->size ? hval : hval % htab->size);

	TYPE val_ptr;
	HASHTYPE hash;

	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	if (hash == hval)
	return -1;
	else if (hash == 0)
	{
	val_ptr = NULL;
	atomic_compare_exchange_strong_explicit(&htab->table[idx].val_ptr,
	(uintptr_t *) &val_ptr,
	(uintptr_t) val,
	memory_order_acquire,
	memory_order_acquire);

	if (val_ptr == NULL)
	{
	atomic_store_explicit(&htab->table[idx].hashval, hval,
	memory_order_release);
	return 0;
	}
	else
	{
	do
	{
	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	}
	while (hash == 0);
	if (hash == hval)
	return -1;
	}
	}

	/* Second hash function as suggested in [Knuth]. */
	HASHTYPE second_hash = 1 + hval % (htab->size - 2);

	for(;;)
	{
	if (idx <= second_hash)
	idx = htab->size + idx - second_hash;
	else
	idx -= second_hash;

	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	if (hash == hval)
	return -1;
	else if (hash == 0)
	{
	val_ptr = NULL;
	atomic_compare_exchange_strong_explicit(&htab->table[idx].val_ptr,
	(uintptr_t *) &val_ptr,
	(uintptr_t) val,
	memory_order_acquire,
	memory_order_acquire);

	if (val_ptr == NULL)
	{
	atomic_store_explicit(&htab->table[idx].hashval, hval,
	memory_order_release);
	return 0;
	}
	else
	{
	do
	{
	hash = atomic_load_explicit(&htab->table[idx].hashval,
	memory_order_acquire);
	}
	while (hash == 0);
	if (hash == hval)
	return -1;
	}
	}
	}
	}

	#define NO_RESIZING 0u
	#define ALLOCATING_MEMORY 1u
	#define MOVING_DATA 3u
	#define CLEANING 2u

	#define STATE_BITS 2u
	#define STATE_INCREMENT (1u << STATE_BITS)
	#define STATE_MASK (STATE_INCREMENT - 1)
	#define GET_STATE(A) ((A) & STATE_MASK)

	#define IS_NO_RESIZE_OR_CLEANING(A) (((A) & 0x1u) == 0)

	#define GET_ACTIVE_WORKERS(A) ((A) >> STATE_BITS)

	#define INITIALIZATION_BLOCK_SIZE 256
	#define MOVE_BLOCK_SIZE 256
	#define CEIL(A, B) (((A) + (B) - 1) / (B))

	/* Initializes records and copies the data from the old table.
	It can share work with other threads */
	static void resize_helper(NAME *htab, int blocking)
	{
	size_t num_old_blocks = CEIL(htab->old_size, MOVE_BLOCK_SIZE);
	size_t num_new_blocks = CEIL(htab->size, INITIALIZATION_BLOCK_SIZE);

	size_t my_block;
	size_t num_finished_blocks = 0;

	while ((my_block = atomic_fetch_add_explicit(&htab->next_init_block, 1,
	memory_order_acquire))
	< num_new_blocks)
	{
	size_t record_it = my_block * INITIALIZATION_BLOCK_SIZE;
	size_t record_end = (my_block + 1) * INITIALIZATION_BLOCK_SIZE;
	if (record_end > htab->size)
	record_end = htab->size;

	while (record_it++ != record_end)
	{
	atomic_init(&htab->table[record_it].hashval, (uintptr_t) NULL);
	atomic_init(&htab->table[record_it].val_ptr, (uintptr_t) NULL);
	}

	num_finished_blocks++;
	}

	atomic_fetch_add_explicit(&htab->num_initialized_blocks,
	num_finished_blocks, memory_order_release);
	while (atomic_load_explicit(&htab->num_initialized_blocks,
	memory_order_acquire) != num_new_blocks);

	/* All block are initialized, start moving */
	num_finished_blocks = 0;
	while ((my_block = atomic_fetch_add_explicit(&htab->next_move_block, 1,
	memory_order_acquire))
	< num_old_blocks)
	{
	size_t record_it = my_block * MOVE_BLOCK_SIZE;
	size_t record_end = (my_block + 1) * MOVE_BLOCK_SIZE;
	if (record_end > htab->old_size)
	record_end = htab->old_size;

	while (record_it++ != record_end)
	{
	TYPE val_ptr = (TYPE) atomic_load_explicit(
	&htab->old_table[record_it].val_ptr,
	memory_order_acquire);
	if (val_ptr == NULL)
	continue;

	HASHTYPE hashval = atomic_load_explicit(
	&htab->old_table[record_it].hashval,
	memory_order_acquire);
	assert(hashval);

	insert_helper(htab, hashval, val_ptr);
	}

	num_finished_blocks++;
	}

	atomic_fetch_add_explicit(&htab->num_moved_blocks, num_finished_blocks,
	memory_order_release);

	if (blocking)
	while (atomic_load_explicit(&htab->num_moved_blocks,
	memory_order_acquire) != num_old_blocks);
	}

	static void
	resize_master(NAME *htab)
	{
	htab->old_size = htab->size;
	htab->old_table = htab->table;

	htab->size = next_prime(htab->size * 2);
	htab->table = malloc((1 + htab->size) * sizeof(htab->table[0]));
	assert(htab->table);

	/* Change state from ALLOCATING_MEMORY to MOVING_DATA */
	atomic_fetch_xor_explicit(&htab->resizing_state,
	ALLOCATING_MEMORY ^ MOVING_DATA,
	memory_order_release);

	resize_helper(htab, 1);

	/* Change state from MOVING_DATA to CLEANING */
	size_t resize_state = atomic_fetch_xor_explicit(&htab->resizing_state,
	MOVING_DATA ^ CLEANING,
	memory_order_acq_rel);
	while (GET_ACTIVE_WORKERS(resize_state) != 0)
	resize_state = atomic_load_explicit(&htab->resizing_state,
	memory_order_acquire);

	/* There are no more active workers */
	atomic_store_explicit(&htab->next_init_block, 0, memory_order_relaxed);
	atomic_store_explicit(&htab->num_initialized_blocks, 0,
	memory_order_relaxed);

	atomic_store_explicit(&htab->next_move_block, 0, memory_order_relaxed);
	atomic_store_explicit(&htab->num_moved_blocks, 0, memory_order_relaxed);

	free(htab->old_table);

	/* Change state to NO_RESIZING */
	atomic_fetch_xor_explicit(&htab->resizing_state, CLEANING ^ NO_RESIZING,
	memory_order_relaxed);

	}

	static void
	resize_worker(NAME *htab)
	{
	size_t resize_state = atomic_load_explicit(&htab->resizing_state,
	memory_order_acquire);

	/* If the resize has finished */
	if (IS_NO_RESIZE_OR_CLEANING(resize_state))
	return;

	/* Register as worker and check if the resize has finished in the meantime*/
	resize_state = atomic_fetch_add_explicit(&htab->resizing_state,
	STATE_INCREMENT,
	memory_order_acquire);
	if (IS_NO_RESIZE_OR_CLEANING(resize_state))
	{
	atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
	memory_order_relaxed);
	return;
	}

	/* Wait while the new table is being allocated. */
	while (GET_STATE(resize_state) == ALLOCATING_MEMORY)
	resize_state = atomic_load_explicit(&htab->resizing_state,
	memory_order_acquire);

	/* Check if the resize is done */
	assert(GET_STATE(resize_state) != NO_RESIZING);
	if (GET_STATE(resize_state) == CLEANING)
	{
	atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
	memory_order_relaxed);
	return;
	}

	resize_helper(htab, 0);

	/* Deregister worker */
	atomic_fetch_sub_explicit(&htab->resizing_state, STATE_INCREMENT,
	memory_order_release);
	}


	int
	#define INIT(name) _INIT (name)
	#define _INIT(name) \
	name##_init
	INIT(NAME) (NAME *htab, size_t init_size)
	{
	/* We need the size to be a prime. */
	init_size = next_prime (init_size);

	/* Initialize the data structure. */
	htab->size = init_size;
	atomic_init(&htab->filled, 0);
	atomic_init(&htab->resizing_state, 0);

	atomic_init(&htab->next_init_block, 0);
	atomic_init(&htab->num_initialized_blocks, 0);

	atomic_init(&htab->next_move_block, 0);
	atomic_init(&htab->num_moved_blocks, 0);

	pthread_rwlock_init(&htab->resize_rwl, NULL);

	htab->table = (void ) malloc ((init_size + 1) sizeof (htab->table[0]));
	if (htab->table == NULL)
	return -1;

	for (size_t i = 0; i <= init_size; i++)
	{
	atomic_init(&htab->table[i].hashval, (uintptr_t) NULL);
	atomic_init(&htab->table[i].val_ptr, (uintptr_t) NULL);
	}

	return 0;
	}


	int
	#define FREE(name) _FREE (name)
	#define _FREE(name) \
	name##_free
	FREE(NAME) (NAME *htab)
	{
	pthread_rwlock_destroy(&htab->resize_rwl);
	free (htab->table);
	return 0;
	}


	int
	#define INSERT(name) _INSERT (name)
	#define _INSERT(name) \
	name##_insert
	INSERT(NAME) (NAME *htab, HASHTYPE hval, TYPE data)
	{
	int incremented = 0;

	for(;;)
	{
	while (pthread_rwlock_tryrdlock(&htab->resize_rwl) != 0)
	resize_worker(htab);

	size_t filled;
	if (!incremented)
	{
	filled = atomic_fetch_add_explicit(&htab->filled, 1,
	memory_order_acquire);
	incremented = 1;
	}
	else
	{
	filled = atomic_load_explicit(&htab->filled,
	memory_order_acquire);
	}


	if (100 * filled > 90 * htab->size)
	{
	/* Table is filled more than 90%. Resize the table. */

	size_t resizing_state = atomic_load_explicit(&htab->resizing_state,
	memory_order_acquire);
	if (resizing_state == 0 &&
	atomic_compare_exchange_strong_explicit(&htab->resizing_state,
	&resizing_state,
	ALLOCATING_MEMORY,
	memory_order_acquire,
	memory_order_acquire))
	{
	/* Master thread */
	pthread_rwlock_unlock(&htab->resize_rwl);

	pthread_rwlock_wrlock(&htab->resize_rwl);
	resize_master(htab);
	pthread_rwlock_unlock(&htab->resize_rwl);

	}
	else
	{
	/* Worker thread */
	pthread_rwlock_unlock(&htab->resize_rwl);
	resize_worker(htab);
	}
	}
	else
	{
	/* Lock acquired, no need for resize*/
	break;
	}
	}

	int ret_val = insert_helper(htab, hval, data);
	if (ret_val == -1)
	atomic_fetch_sub_explicit(&htab->filled, 1, memory_order_relaxed);
	pthread_rwlock_unlock(&htab->resize_rwl);
	return ret_val;
	}



	TYPE
	#define FIND(name) _FIND (name)
	#define _FIND(name) \
	name##_find
	FIND(NAME) (NAME *htab, HASHTYPE hval)
	{
	while (pthread_rwlock_tryrdlock(&htab->resize_rwl) != 0)
	resize_worker(htab);

	size_t idx;

	/* Make the hash data nonzero. */
	hval = hval ?: 1;
	idx = lookup(htab, hval);

	if (idx == 0)
	{
	pthread_rwlock_unlock(&htab->resize_rwl);
	return NULL;
	}

	/* get a copy before unlocking the lock */
	TYPE ret_val = (TYPE) atomic_load_explicit(&htab->table[idx].val_ptr,
	memory_order_relaxed);

	pthread_rwlock_unlock(&htab->resize_rwl);
	return ret_val;
	}