ircd-hybrid-8/src/balloc.c

/*
 *  ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd).
 *
 *  Copyright (C) 2002 by the past and present ircd coders, and others.
 *  Original credit lines follow:
 *
 *  File:   balloc.c
 *  Owner:  Wohali (Joan Touzet)
 *  
 *  Modified 2001/11/29 for mmap() support by Aaron Sethman <androsyn@ratbox.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of 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.
 *
 *  This program 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 a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 */

/*! \file balloc.c
 * \brief A block allocator
 * \version $Id$
 * 
 * About the block allocator
 *
 * Basically we have three ways of getting memory off of the operating
 * system. Below are this list of methods and the order of preference.
 *
 * 1. mmap() anonymous pages with the MMAP_ANON flag.\n
 * 2. mmap() via the /dev/zero trick.\n
 * 3. malloc()\n
 *
 * The advantages of 1 and 2 are this.  We can munmap() the pages which will
 * return the pages back to the operating system, thus reducing the size 
 * of the process as the memory is unused.  malloc() on many systems just keeps
 * a heap of memory to itself, which never gets given back to the OS, except on
 * exit.  This of course is bad, if say we have an event that causes us to allocate
 * say, 200MB of memory, while our normal memory consumption would be 15MB.  In the
 * malloc() case, the amount of memory allocated to our process never goes down, as
 * malloc() has it locked up in its heap.  With the mmap() method, we can munmap()
 * the block and return it back to the OS, thus causing our memory consumption to go
 * down after we no longer need it.
 */

#include "stdinc.h"
#ifdef HAVE_MMAP /* We've got mmap() that is good */
#include <sys/mman.h>

/* HP-UX sucks */
#ifdef MAP_ANONYMOUS
#ifndef MAP_ANON
#define MAP_ANON MAP_ANONYMOUS
#endif
#endif /* MAP_ANONYMOUS */
#endif

#include "ircd.h"
#include "balloc.h"
#include "irc_string.h"
#include "tools.h"
#include "client.h"
#include "send.h"
#include "numeric.h"
#include "fdlist.h"
#include "event.h"


static BlockHeap *heap_list = NULL;

static int BlockHeapGarbageCollect(BlockHeap *);
static void heap_garbage_collection(void *);

/*! \brief Returns memory for the block back to either the malloc heap
 *         in case of !HAVE_MMAP, or back to the OS otherwise.
 * \param ptr  Pointer to memory to be freed
 * \param size The size of the memory space
 */
static inline void
free_block(void *ptr, size_t size)
{
#ifdef HAVE_MMAP
  munmap(ptr, size);
#else
  free(ptr);
#endif
}

#ifdef HAVE_MMAP
#ifndef MAP_ANON /* But we cannot mmap() anonymous pages */
                 /* So we mmap() /dev/zero, which is just as good */
static int zero_fd = -1;
#endif
#endif

/*! \brief Opens /dev/zero and saves the file handle for
 * future allocations.
 */
void
initBlockHeap(void)
{
#ifdef HAVE_MMAP
#ifndef MAP_ANON
  zero_fd = open("/dev/zero", O_RDWR);

  if (zero_fd < 0)
    outofmemory();
  fd_open(zero_fd, 0, "Anonymous mmap()");
#endif
  eventAdd("heap_garbage_collection", &heap_garbage_collection, NULL, 119);
#endif
}

/*!
 * \param size Size of block to allocate
 * \return Address pointer to allocated data space
 */
static inline void *
get_block(size_t size)
{
#ifdef HAVE_MMAP
  void *ptr = NULL;

#ifndef MAP_ANON
  ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
#else
  ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
#endif
  return ptr == MAP_FAILED ? NULL : ptr;
#else
  return malloc(size);
#endif
}

static void
heap_garbage_collection(void *arg)
{
  BlockHeap *bh;

  for (bh = heap_list; bh != NULL; bh = bh->next)
    BlockHeapGarbageCollect(bh);
}

/*! \brief Allocates a new block for addition to a blockheap
 * \param bh Pointer to parent blockheap
 * \return 0 if successful, 1 if not
 */
static int
newblock(BlockHeap *bh)
{
  MemBlock *newblk = NULL;
  Block *b = NULL;
  int i = 0;
  void *offset = NULL;

  /* Setup the initial data structure. */
  if ((b = calloc(1, sizeof(Block))) == NULL)
    return 1;

  b->freeElems = bh->elemsPerBlock;
  b->next = bh->base;
  b->alloc_size = bh->elemsPerBlock * (bh->elemSize + sizeof(MemBlock));
  b->elems = get_block(b->alloc_size);

  if (b->elems == NULL)
    return 1;

  offset = b->elems;

  /* Setup our blocks now */
  for (; i < bh->elemsPerBlock; ++i)
  {
    void *data;

    newblk = offset;
    newblk->block = b;
    data = (void *)((size_t)offset + sizeof(MemBlock));

    dlinkAdd(data, &newblk->self, &b->free_list);
    offset = (unsigned char *)((unsigned char *)offset + bh->elemSize + sizeof(MemBlock));
  }

  ++bh->blocksAllocated;
  bh->freeElems += bh->elemsPerBlock;
  bh->base = b;

  return 0;
}

/*! \brief Creates a new blockheap
 *
 * Creates a new blockheap from which smaller blocks can be allocated.
 * Intended to be used instead of multiple calls to malloc() when
 * performance is an issue.
 *
 * \param name          Name of the blockheap
 * \param elemsize      Size of the basic element to be stored
 * \param elemsperblock Number of elements to be stored in a single block of
 *                      memory.  When the blockheap runs out of free memory,
 *                      it will allocate elemsize * elemsperblock more.
 * \return Pointer to new BlockHeap, or NULL if unsuccessful
 */
BlockHeap *
BlockHeapCreate(const char *const name, size_t elemsize, int elemsperblock)
{
  BlockHeap *bh = NULL;
  assert(elemsize > 0 && elemsperblock > 0);

  /* Catch idiotic requests up front */
  if ((elemsize <= 0) || (elemsperblock <= 0))
    outofmemory();    /* die.. out of memory */

  /* Allocate our new BlockHeap */
  if ((bh = calloc(1, sizeof(BlockHeap))) == NULL)
    outofmemory();    /* die.. out of memory */

  if ((elemsize % sizeof(void *)) != 0)
  {
    /* Pad to even pointer boundary */
    elemsize += sizeof(void *);
    elemsize &= ~(sizeof(void *) - 1);
  }

  bh->name = name;
  bh->elemSize = elemsize;
  bh->elemsPerBlock = elemsperblock;

  /* Be sure our malloc was successful */
  if (newblock(bh))
  {
    if (bh != NULL)
      free(bh);

     outofmemory();    /* die.. out of memory */
  }

  assert(bh);

  bh->next = heap_list;
  heap_list = bh;

  return bh;
}

/*! \brief Returns a pointer to a struct within our BlockHeap that's free for
 *         the taking.
 * \param bh Pointer to the Blockheap
 * \return Address pointer to allocated data space, or NULL if unsuccessful
 */
void *
BlockHeapAlloc(BlockHeap *bh)
{
  Block *walker = NULL;
  dlink_node *new_node = NULL;

  assert(bh != NULL);

  if (bh->freeElems == 0)
  {   
    /* Allocate new block and assign */
    /* newblock returns 1 if unsuccessful, 0 if not */
    if (newblock(bh))
    {
      /* That didn't work..try to garbage collect */
      BlockHeapGarbageCollect(bh);  

      if (newblock(bh))
        outofmemory(); /* Well that didn't work either...bail */
    }
  }
      
  for (walker = bh->base; walker != NULL; walker = walker->next)
  {
    if (walker->freeElems > 0)
    {
      --bh->freeElems;
      --walker->freeElems;
      new_node = walker->free_list.head;

      dlinkDelete(new_node, &walker->free_list);
      dlinkAdd(new_node->data, new_node, &walker->used_list);
      assert(new_node->data != NULL);

      memset(new_node->data, 0, bh->elemSize);
      return new_node->data;
    }
  }

  assert(0 == 1);
  outofmemory();
  return NULL;
}

/*! \brief Returns an element to the free pool, does not free()
 * \param bh  Pointer to BlockHeap containing element
 * \param ptr Pointer to element to be "freed"
 * \return 0 if successful, 1 if element not contained within BlockHeap
 */
int
BlockHeapFree(BlockHeap *bh, void *ptr)
{
  Block *block = NULL;
  struct MemBlock *memblock = NULL;
    
  assert(bh != NULL);
  assert(ptr != NULL);

  memblock = (void *)((size_t)ptr - sizeof(MemBlock));
  assert(memblock->block != NULL);

  if (memblock->block == NULL)
    outofmemory();

  /* Is this block really on the used list? */
  assert(dlinkFind(&memblock->block->used_list, ptr) != NULL); 

  block = memblock->block;
  ++bh->freeElems;
  ++block->freeElems;
  mem_frob(ptr, bh->elemSize);

  dlinkDelete(&memblock->self, &block->used_list);
  dlinkAdd(ptr, &memblock->self, &block->free_list);
  return 0;
}

/*! \brief Performs garbage collection on the block heap.
 *
 * Performs garbage collection on the block heap.  Any blocks that are
 * completely unallocated are removed from the heap.  Garbage collection
 * will \b never remove the root node of the heap.
 *
 * \param bh Pointer to the BlockHeap to be cleaned up
 * \return 0 if successful, 1 if bh == NULL
 */
static int
BlockHeapGarbageCollect(BlockHeap *bh)
{
  Block *walker = NULL, *last = NULL;

  if (bh == NULL)
    return 1;

  if (bh->freeElems < bh->elemsPerBlock || bh->blocksAllocated == 1)
  {
    /* There couldn't possibly be an entire free block.  Return. */
    return 0;
  }

  walker = bh->base;

  while (walker != NULL)
  {
    if (walker->freeElems == bh->elemsPerBlock)
    {
      free_block(walker->elems, walker->alloc_size);

      if (last != NULL)
      {
        last->next = walker->next;

        if (walker != NULL)
          free(walker);
        walker = last->next;
      }
      else
      {
        bh->base = walker->next;

        if (walker != NULL)
          free(walker);
        walker = bh->base;
      }

      --bh->blocksAllocated;
      bh->freeElems -= bh->elemsPerBlock;
    }
    else
    {
      last = walker;
      walker = walker->next;
    }
  }

  return 0;
}

/*! \brief Completely free()s a BlockHeap.  Use for cleanup.
 * \param bh Pointer to the BlockHeap to be destroyed
 * \return 0 if successful, 1 if bh == NULL
 */
int
BlockHeapDestroy(BlockHeap *bh)
{
  Block *walker = NULL, *next = NULL;

  if (bh == NULL)
    return 1;

  for (walker = bh->base; walker != NULL; walker = next)
  {
    next = walker->next;
    free_block(walker->elems, walker->alloc_size);

    if (walker != NULL)
      free(walker);
  }

  if (heap_list == bh)
    heap_list = bh->next;
  else {
    BlockHeap *prev;

    for (prev = heap_list; prev->next != bh; prev = prev->next)
      /* nothing */ ;
    prev->next = bh->next;
  }

  free(bh);
  return 0;
}

/*! \brief Returns the number of bytes being used
 * \param bh Pointer to a BlockHeap
 * \return Number of bytes being used
 */
static size_t
block_heap_get_used_mem(const BlockHeap *const bh)
{
  return(((bh->blocksAllocated *
           bh->elemsPerBlock)-bh->freeElems) *
          (bh->elemSize + sizeof(MemBlock)));
}

/*! \brief Returns the number of bytes being free for further allocations
 * \param bh Pointer to a BlockHeap
 * \return Number of bytes being free for further allocations
 */
static size_t
block_heap_get_free_mem(const BlockHeap *const bh)
{
  return(bh->freeElems * (bh->elemSize + sizeof(MemBlock)));
}

/*! \brief Returns the total number of bytes of memory belonging to a heap
 * \param bh Pointer to a BlockHeap
 * \return Total number of bytes of memory belonging to a heap
 */
static size_t
block_heap_get_size_mem(const BlockHeap *const bh)
{
  return(((bh->blocksAllocated *
           bh->elemsPerBlock)) *
          (bh->elemSize + sizeof(MemBlock)));
}

/*! \brief Returns the number of elements being used.
 * \param bh Pointer to a BlockHeap
 * \return Number of elements being free for further allocations
 */
static unsigned int
block_heap_get_used_elm(const BlockHeap *const bh)
{
  return((bh->blocksAllocated *
          bh->elemsPerBlock)-bh->freeElems);
}

/*! \brief Returns the number of elements being free for further allocations.
 * \param bh Pointer to a BlockHeap
 * \return Number of elements being free for further allocations
 */
static unsigned int
block_heap_get_free_elm(const BlockHeap *const bh)
{
  return(bh->freeElems);
}

/*! \brief Returns the number of total elements belonging to a heap.
 *         Includes \b free and \b used elements.
 * \param bh Pointer to a BlockHeap
 * \return Number of total elements belonging to a heap
 */
static unsigned int
block_heap_get_size_elm(const BlockHeap *const bh)
{
  return(bh->blocksAllocated * bh->elemsPerBlock);
}

void
block_heap_report_stats(struct Client *client_p)
{
  const BlockHeap *bh = NULL;

  for (bh = heap_list; bh != NULL; bh = bh->next)
    sendto_one(client_p, ":%s %d %s z :%s mempool: used %u/%u free %u/%u (size %u/%u)",
               me.name, RPL_STATSDEBUG, client_p->name, bh->name,
               block_heap_get_used_elm(bh),
               block_heap_get_used_mem(bh),
               block_heap_get_free_elm(bh),
               block_heap_get_free_mem(bh),
               block_heap_get_size_elm(bh),
               block_heap_get_size_mem(bh));
}
Revision:	367
Committed:	Mon Jan 9 23:37:29 2006 UTC (20 years, 6 months ago) by michael
Content type:	text/x-csrc
Original Path:	*ircd-hybrid-7.2/src/balloc.c*
File size:	13238 byte(s)
Log Message:	- Fixed compile error on srv4 as reported by KEYofR
#	Content
1	/*
2	* ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd).
3	*
4	* Copyright (C) 2002 by the past and present ircd coders, and others.
5	* Original credit lines follow:
6	*
7	* File: balloc.c
8	* Owner: Wohali (Joan Touzet)
9	*
10	* Modified 2001/11/29 for mmap() support by Aaron Sethman <androsyn@ratbox.org>
11	*
12	* This program is free software; you can redistribute it and/or modify
13	* it under the terms of the GNU General Public License as published by
14	* the Free Software Foundation; either version 2 of the License, or
15	* (at your option) any later version.
16	*
17	* This program is distributed in the hope that it will be useful,
18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20	* GNU General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, write to the Free Software
24	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
25	* USA
26	*/
27
28	/*! \file balloc.c
29	* \brief A block allocator
30	* \version $Id$
31	*
32	* About the block allocator
33	*
34	* Basically we have three ways of getting memory off of the operating
35	* system. Below are this list of methods and the order of preference.
36	*
37	* 1. mmap() anonymous pages with the MMAP_ANON flag.\n
38	* 2. mmap() via the /dev/zero trick.\n
39	* 3. malloc()\n
40	*
41	* The advantages of 1 and 2 are this. We can munmap() the pages which will
42	* return the pages back to the operating system, thus reducing the size
43	* of the process as the memory is unused. malloc() on many systems just keeps
44	* a heap of memory to itself, which never gets given back to the OS, except on
45	* exit. This of course is bad, if say we have an event that causes us to allocate
46	* say, 200MB of memory, while our normal memory consumption would be 15MB. In the
47	* malloc() case, the amount of memory allocated to our process never goes down, as
48	* malloc() has it locked up in its heap. With the mmap() method, we can munmap()
49	* the block and return it back to the OS, thus causing our memory consumption to go
50	* down after we no longer need it.
51	*/
52
53	#include "stdinc.h"
54	#ifdef HAVE_MMAP /* We've got mmap() that is good */
55	#include <sys/mman.h>
56
57	/* HP-UX sucks */
58	#ifdef MAP_ANONYMOUS
59	#ifndef MAP_ANON
60	#define MAP_ANON MAP_ANONYMOUS
61	#endif
62	#endif /* MAP_ANONYMOUS */
63	#endif
64
65	#include "ircd.h"
66	#include "balloc.h"
67	#include "irc_string.h"
68	#include "tools.h"
69	#include "client.h"
70	#include "send.h"
71	#include "numeric.h"
72	#include "fdlist.h"
73	#include "event.h"
74
75
76	static BlockHeap *heap_list = NULL;
77
78	static int BlockHeapGarbageCollect(BlockHeap *);
79	static void heap_garbage_collection(void *);
80
81	/*! \brief Returns memory for the block back to either the malloc heap
82	* in case of !HAVE_MMAP, or back to the OS otherwise.
83	* \param ptr Pointer to memory to be freed
84	* \param size The size of the memory space
85	*/
86	static inline void
87	free_block(void *ptr, size_t size)
88	{
89	#ifdef HAVE_MMAP
90	munmap(ptr, size);
91	#else
92	free(ptr);
93	#endif
94	}
95
96	#ifdef HAVE_MMAP
97	#ifndef MAP_ANON /* But we cannot mmap() anonymous pages */
98	/* So we mmap() /dev/zero, which is just as good */
99	static int zero_fd = -1;
100	#endif
101	#endif
102
103	/*! \brief Opens /dev/zero and saves the file handle for
104	* future allocations.
105	*/
106	void
107	initBlockHeap(void)
108	{
109	#ifdef HAVE_MMAP
110	#ifndef MAP_ANON
111	zero_fd = open("/dev/zero", O_RDWR);
112
113	if (zero_fd < 0)
114	outofmemory();
115	fd_open(zero_fd, 0, "Anonymous mmap()");
116	#endif
117	eventAdd("heap_garbage_collection", &heap_garbage_collection, NULL, 119);
118	#endif
119	}
120
121	/*!
122	* \param size Size of block to allocate
123	* \return Address pointer to allocated data space
124	*/
125	static inline void *
126	get_block(size_t size)
127	{
128	#ifdef HAVE_MMAP
129	void *ptr = NULL;
130
131	#ifndef MAP_ANON
132	ptr = mmap(NULL, size, PROT_READ \| PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
133	#else
134	ptr = mmap(NULL, size, PROT_READ \| PROT_WRITE, MAP_PRIVATE \| MAP_ANON, -1, 0);
135	#endif
136	return ptr == MAP_FAILED ? NULL : ptr;
137	#else
138	return malloc(size);
139	#endif
140	}
141
142	static void
143	heap_garbage_collection(void *arg)
144	{
145	BlockHeap *bh;
146
147	for (bh = heap_list; bh != NULL; bh = bh->next)
148	BlockHeapGarbageCollect(bh);
149	}
150
151	/*! \brief Allocates a new block for addition to a blockheap
152	* \param bh Pointer to parent blockheap
153	* \return 0 if successful, 1 if not
154	*/
155	static int
156	newblock(BlockHeap *bh)
157	{
158	MemBlock *newblk = NULL;
159	Block *b = NULL;
160	int i = 0;
161	void *offset = NULL;
162
163	/* Setup the initial data structure. */
164	if ((b = calloc(1, sizeof(Block))) == NULL)
165	return 1;
166
167	b->freeElems = bh->elemsPerBlock;
168	b->next = bh->base;
169	b->alloc_size = bh->elemsPerBlock * (bh->elemSize + sizeof(MemBlock));
170	b->elems = get_block(b->alloc_size);
171
172	if (b->elems == NULL)
173	return 1;
174
175	offset = b->elems;
176
177	/* Setup our blocks now */
178	for (; i < bh->elemsPerBlock; ++i)
179	{
180	void *data;
181
182	newblk = offset;
183	newblk->block = b;
184	data = (void *)((size_t)offset + sizeof(MemBlock));
185
186	dlinkAdd(data, &newblk->self, &b->free_list);
187	offset = (unsigned char )((unsigned char )offset + bh->elemSize + sizeof(MemBlock));
188	}
189
190	++bh->blocksAllocated;
191	bh->freeElems += bh->elemsPerBlock;
192	bh->base = b;
193
194	return 0;
195	}
196
197	/*! \brief Creates a new blockheap
198	*
199	* Creates a new blockheap from which smaller blocks can be allocated.
200	* Intended to be used instead of multiple calls to malloc() when
201	* performance is an issue.
202	*
203	* \param name Name of the blockheap
204	* \param elemsize Size of the basic element to be stored
205	* \param elemsperblock Number of elements to be stored in a single block of
206	* memory. When the blockheap runs out of free memory,
207	* it will allocate elemsize * elemsperblock more.
208	* \return Pointer to new BlockHeap, or NULL if unsuccessful
209	*/
210	BlockHeap *
211	BlockHeapCreate(const char *const name, size_t elemsize, int elemsperblock)
212	{
213	BlockHeap *bh = NULL;
214	assert(elemsize > 0 && elemsperblock > 0);
215
216	/* Catch idiotic requests up front */
217	if ((elemsize <= 0) \|\| (elemsperblock <= 0))
218	outofmemory(); /* die.. out of memory */
219
220	/* Allocate our new BlockHeap */
221	if ((bh = calloc(1, sizeof(BlockHeap))) == NULL)
222	outofmemory(); /* die.. out of memory */
223
224	if ((elemsize % sizeof(void *)) != 0)
225	{
226	/* Pad to even pointer boundary */
227	elemsize += sizeof(void *);
228	elemsize &= ~(sizeof(void *) - 1);
229	}
230
231	bh->name = name;
232	bh->elemSize = elemsize;
233	bh->elemsPerBlock = elemsperblock;
234
235	/* Be sure our malloc was successful */
236	if (newblock(bh))
237	{
238	if (bh != NULL)
239	free(bh);
240
241	outofmemory(); /* die.. out of memory */
242	}
243
244	assert(bh);
245
246	bh->next = heap_list;
247	heap_list = bh;
248
249	return bh;
250	}
251
252	/*! \brief Returns a pointer to a struct within our BlockHeap that's free for
253	* the taking.
254	* \param bh Pointer to the Blockheap
255	* \return Address pointer to allocated data space, or NULL if unsuccessful
256	*/
257	void *
258	BlockHeapAlloc(BlockHeap *bh)
259	{
260	Block *walker = NULL;
261	dlink_node *new_node = NULL;
262
263	assert(bh != NULL);
264
265	if (bh->freeElems == 0)
266	{
267	/* Allocate new block and assign */
268	/* newblock returns 1 if unsuccessful, 0 if not */
269	if (newblock(bh))
270	{
271	/* That didn't work..try to garbage collect */
272	BlockHeapGarbageCollect(bh);
273
274	if (newblock(bh))
275	outofmemory(); /* Well that didn't work either...bail */
276	}
277	}
278
279	for (walker = bh->base; walker != NULL; walker = walker->next)
280	{
281	if (walker->freeElems > 0)
282	{
283	--bh->freeElems;
284	--walker->freeElems;
285	new_node = walker->free_list.head;
286
287	dlinkDelete(new_node, &walker->free_list);
288	dlinkAdd(new_node->data, new_node, &walker->used_list);
289	assert(new_node->data != NULL);
290
291	memset(new_node->data, 0, bh->elemSize);
292	return new_node->data;
293	}
294	}
295
296	assert(0 == 1);
297	outofmemory();
298	return NULL;
299	}
300
301	/*! \brief Returns an element to the free pool, does not free()
302	* \param bh Pointer to BlockHeap containing element
303	* \param ptr Pointer to element to be "freed"
304	* \return 0 if successful, 1 if element not contained within BlockHeap
305	*/
306	int
307	BlockHeapFree(BlockHeap bh, void ptr)
308	{
309	Block *block = NULL;
310	struct MemBlock *memblock = NULL;
311
312	assert(bh != NULL);
313	assert(ptr != NULL);
314
315	memblock = (void *)((size_t)ptr - sizeof(MemBlock));
316	assert(memblock->block != NULL);
317
318	if (memblock->block == NULL)
319	outofmemory();
320
321	/* Is this block really on the used list? */
322	assert(dlinkFind(&memblock->block->used_list, ptr) != NULL);
323
324	block = memblock->block;
325	++bh->freeElems;
326	++block->freeElems;
327	mem_frob(ptr, bh->elemSize);
328
329	dlinkDelete(&memblock->self, &block->used_list);
330	dlinkAdd(ptr, &memblock->self, &block->free_list);
331	return 0;
332	}
333
334	/*! \brief Performs garbage collection on the block heap.
335	*
336	* Performs garbage collection on the block heap. Any blocks that are
337	* completely unallocated are removed from the heap. Garbage collection
338	* will \b never remove the root node of the heap.
339	*
340	* \param bh Pointer to the BlockHeap to be cleaned up
341	* \return 0 if successful, 1 if bh == NULL
342	*/
343	static int
344	BlockHeapGarbageCollect(BlockHeap *bh)
345	{
346	Block walker = NULL, last = NULL;
347
348	if (bh == NULL)
349	return 1;
350
351	if (bh->freeElems < bh->elemsPerBlock \|\| bh->blocksAllocated == 1)
352	{
353	/* There couldn't possibly be an entire free block. Return. */
354	return 0;
355	}
356
357	walker = bh->base;
358
359	while (walker != NULL)
360	{
361	if (walker->freeElems == bh->elemsPerBlock)
362	{
363	free_block(walker->elems, walker->alloc_size);
364
365	if (last != NULL)
366	{
367	last->next = walker->next;
368
369	if (walker != NULL)
370	free(walker);
371	walker = last->next;
372	}
373	else
374	{
375	bh->base = walker->next;
376
377	if (walker != NULL)
378	free(walker);
379	walker = bh->base;
380	}
381
382	--bh->blocksAllocated;
383	bh->freeElems -= bh->elemsPerBlock;
384	}
385	else
386	{
387	last = walker;
388	walker = walker->next;
389	}
390	}
391
392	return 0;
393	}
394
395	/*! \brief Completely free()s a BlockHeap. Use for cleanup.
396	* \param bh Pointer to the BlockHeap to be destroyed
397	* \return 0 if successful, 1 if bh == NULL
398	*/
399	int
400	BlockHeapDestroy(BlockHeap *bh)
401	{
402	Block walker = NULL, next = NULL;
403
404	if (bh == NULL)
405	return 1;
406
407	for (walker = bh->base; walker != NULL; walker = next)
408	{
409	next = walker->next;
410	free_block(walker->elems, walker->alloc_size);
411
412	if (walker != NULL)
413	free(walker);
414	}
415
416	if (heap_list == bh)
417	heap_list = bh->next;
418	else {
419	BlockHeap *prev;
420
421	for (prev = heap_list; prev->next != bh; prev = prev->next)
422	/* nothing */ ;
423	prev->next = bh->next;
424	}
425
426	free(bh);
427	return 0;
428	}
429
430	/*! \brief Returns the number of bytes being used
431	* \param bh Pointer to a BlockHeap
432	* \return Number of bytes being used
433	*/
434	static size_t
435	block_heap_get_used_mem(const BlockHeap *const bh)
436	{
437	return(((bh->blocksAllocated *
438	bh->elemsPerBlock)-bh->freeElems) *
439	(bh->elemSize + sizeof(MemBlock)));
440	}
441
442	/*! \brief Returns the number of bytes being free for further allocations
443	* \param bh Pointer to a BlockHeap
444	* \return Number of bytes being free for further allocations
445	*/
446	static size_t
447	block_heap_get_free_mem(const BlockHeap *const bh)
448	{
449	return(bh->freeElems * (bh->elemSize + sizeof(MemBlock)));
450	}
451
452	/*! \brief Returns the total number of bytes of memory belonging to a heap
453	* \param bh Pointer to a BlockHeap
454	* \return Total number of bytes of memory belonging to a heap
455	*/
456	static size_t
457	block_heap_get_size_mem(const BlockHeap *const bh)
458	{
459	return(((bh->blocksAllocated *
460	bh->elemsPerBlock)) *
461	(bh->elemSize + sizeof(MemBlock)));
462	}
463
464	/*! \brief Returns the number of elements being used.
465	* \param bh Pointer to a BlockHeap
466	* \return Number of elements being free for further allocations
467	*/
468	static unsigned int
469	block_heap_get_used_elm(const BlockHeap *const bh)
470	{
471	return((bh->blocksAllocated *
472	bh->elemsPerBlock)-bh->freeElems);
473	}
474
475	/*! \brief Returns the number of elements being free for further allocations.
476	* \param bh Pointer to a BlockHeap
477	* \return Number of elements being free for further allocations
478	*/
479	static unsigned int
480	block_heap_get_free_elm(const BlockHeap *const bh)
481	{
482	return(bh->freeElems);
483	}
484
485	/*! \brief Returns the number of total elements belonging to a heap.
486	* Includes \b free and \b used elements.
487	* \param bh Pointer to a BlockHeap
488	* \return Number of total elements belonging to a heap
489	*/
490	static unsigned int
491	block_heap_get_size_elm(const BlockHeap *const bh)
492	{
493	return(bh->blocksAllocated * bh->elemsPerBlock);
494	}
495
496	void
497	block_heap_report_stats(struct Client *client_p)
498	{
499	const BlockHeap *bh = NULL;
500
501	for (bh = heap_list; bh != NULL; bh = bh->next)
502	sendto_one(client_p, ":%s %d %s z :%s mempool: used %u/%u free %u/%u (size %u/%u)",
503	me.name, RPL_STATSDEBUG, client_p->name, bh->name,
504	block_heap_get_used_elm(bh),
505	block_heap_get_used_mem(bh),
506	block_heap_get_free_elm(bh),
507	block_heap_get_free_mem(bh),
508	block_heap_get_size_elm(bh),
509	block_heap_get_size_mem(bh));
510	}