/** Return a pointer to a chunk of memory in <b>area</b> of at least <b>sz</b>
* bytes. <b>sz</b> should be significantly smaller than the area's chunk
* size, though we can deal if it isn't. */
void *
memarea_alloc(memarea_t *area, size_t sz)
{
memarea_chunk_t *chunk = area->first;
char *result;
tor_assert(chunk);
if (sz == 0)
sz = 1;
if (chunk->next_mem+sz > chunk->u.mem+chunk->mem_size) {
if (sz+CHUNK_HEADER_SIZE >= CHUNK_SIZE) {
/* This allocation is too big. Stick it in a special chunk, and put
* that chunk second in the list. */
memarea_chunk_t *new_chunk = alloc_chunk(sz+CHUNK_HEADER_SIZE, 0);
new_chunk->next_chunk = chunk->next_chunk;
chunk->next_chunk = new_chunk;
chunk = new_chunk;
} else {
memarea_chunk_t *new_chunk = alloc_chunk(CHUNK_SIZE, 1);
new_chunk->next_chunk = chunk;
area->first = chunk = new_chunk;
}
tor_assert(chunk->mem_size >= sz);
}
result = chunk->next_mem;
chunk->next_mem = chunk->next_mem + sz;
// XXXX021 remove these once bug 930 is solved.
tor_assert(chunk->next_mem >= chunk->u.mem);
tor_assert(chunk->next_mem <= chunk->u.mem+chunk->mem_size);
chunk->next_mem = realign_pointer(chunk->next_mem);
return result;
}
static void *
alloc_do_malloc (struct Alloc *alloc, uint32_t size)
{
if (size < (alloc->default_mmap_size - chunk_overhead ()))
{
uint8_t bucket = size_to_bucket (size);
if (alloc->buckets[bucket] != 0)
{
// fast path.
struct AllocAvailable *avail = alloc->buckets[bucket];
MARK_DEFINED (avail, sizeof (void *));
struct AllocAvailable *next = avail->next;
MARK_UNDEFINED (avail, sizeof (void *));
alloc->buckets[bucket] = next;
REPORT_MALLOC (avail, size);
return (uint8_t *) avail;
}
// slow path
struct AllocAvailable *avail = (struct AllocAvailable *)
alloc_brk (alloc, bucket_to_size (bucket));
REPORT_MALLOC (avail, size);
avail->next = 0;
return (uint8_t *) avail;
}
else
{
alloc_chunk (alloc, size + chunk_overhead ());
uint8_t *buffer = alloc_brk (alloc, size);
REPORT_MALLOC (buffer, size);
return buffer;
}
}
void* kmalloc(uint32_t len) {
len += sizeof(kheader_t);
kheader_t *cur_header = kheap_first, *prev_header = 0;
while (cur_header) {
if (cur_header->allocated == 0 && cur_header->length >= len) {
split_chunk(cur_header, len);
cur_header->allocated = 1;
return (void*) ((uint32_t) cur_header + sizeof(kheader_t));
}
prev_header = cur_header;
cur_header = cur_header->next;
}
uint32_t chunk_start;
if (prev_header)
chunk_start = (uint32_t) prev_header + prev_header->length;
else {
chunk_start = KHEAP_START;
kheap_first = (kheader_t *) chunk_start;
}
alloc_chunk(chunk_start, len);
cur_header = (kheader_t *) chunk_start;
cur_header->prev = prev_header;
cur_header->next = 0;
cur_header->allocated = 1;
cur_header->length = len;
prev_header->next = cur_header;
return (void*) (chunk_start + sizeof(kheader_t));
}
/** Allocate and return new memarea. */
memarea_t *
memarea_new(void)
{
memarea_t *head = tor_malloc(sizeof(memarea_t));
head->first = alloc_chunk(CHUNK_SIZE, 1);
return head;
}
int git_revwalk_new(git_revwalk **revwalk_out, git_repository *repo)
{
git_revwalk *walk;
walk = git__malloc(sizeof(git_revwalk));
if (walk == NULL)
return GIT_ENOMEM;
memset(walk, 0x0, sizeof(git_revwalk));
walk->commits = git_hashtable_alloc(64,
object_table_hash,
(git_hash_keyeq_ptr)git_oid_cmp);
if (walk->commits == NULL) {
free(walk);
return GIT_ENOMEM;
}
git_pqueue_init(&walk->iterator_time, 8, commit_time_cmp);
git_vector_init(&walk->memory_alloc, 8, NULL);
alloc_chunk(walk);
walk->get_next = &revwalk_next_unsorted;
walk->enqueue = &revwalk_enqueue_unsorted;
walk->repo = repo;
*revwalk_out = walk;
return GIT_SUCCESS;
}
void*
al_malloc(size_t bytes)
{
/*
* the allocator must has been initialized
* bytes must > 0
*/
void* ret;
assert(bytes > 0);
if (bytes > MAX_BYTES) {
ret = malloc(bytes + PREFIX_SIZE);
*(size_t*)ret = NFREELISTS;
ret = (byte_t*)ret + PREFIX_SIZE;
}
else {
struct allocator_t* self = &_s_allocator;
size_t index = freelist_index(bytes);
spinlock_lock(&self->spinlock);
if (NULL == self->free_list[index])
alloc_chunk(self, index);
ret = (byte_t*)self->free_list[index] + PREFIX_SIZE;
self->free_list[index] = self->free_list[index]->next;
spinlock_unlock(&self->spinlock);
}
return ret;
}
address OsMemory_allocate_chunk(size_t initial_size,
size_t max_size, size_t alignment)
{
// make it page aligned
max_size = page_align_up(max_size);
address chunk = anon_mmap(NULL, max_size);
if (chunk == MAP_FAILED) {
return NULL;
}
GUARANTEE((juint)chunk % alignment == 0, "must be aligned");
GUARANTEE((juint)chunk % SysPageSize == 0, "must be page aligned");
size_t aligned_size = page_align_up(initial_size);
alloc_chunk(chunk, aligned_size, max_size);
if (max_size > aligned_size) {
protect_area(chunk + aligned_size, max_size - aligned_size);
}
return chunk;
}
SLJIT_API_FUNC_ATTRIBUTE void* sljit_malloc_exec(sljit_uw size)
{
sljit_uw *ptr = (sljit_uw *)alloc_chunk(size + sizeof (sljit_uw));
*ptr = size;
return (void*)(ptr + 1);
}
static void monte_run(void)
{
print_chunk("Seed", seed, 0);
chunk_t MDi_3 = alloc_chunk(seed.len, "MDi_3");
chunk_t MDi_2 = alloc_chunk(seed.len, "MDi_2");
chunk_t MDi_1 = alloc_chunk(seed.len, "MDi_1");
chunk_t Mi = alloc_chunk(3 * seed.len, "Mi");
for (int j = 0; j < 100; j++) {
//MD[0] = MD[1] = MD[2] = Seed
memcpy(MDi_3.ptr, seed.ptr, seed.len);
memcpy(MDi_2.ptr, seed.ptr, seed.len);
memcpy(MDi_1.ptr, seed.ptr, seed.len);
for (int i = 3; i < 1003; i++) {
// shuffle
chunk_t tmp = MDi_3;
MDi_3 = MDi_2;
MDi_2 = MDi_1;
MDi_1 = seed;
seed = tmp;
// M[i] = MD[i-3] || MD[i-2] || MD[i-1];
memcpy(Mi.ptr + seed.len * 0, MDi_3.ptr, seed.len);
memcpy(Mi.ptr + seed.len * 1, MDi_2.ptr, seed.len);
memcpy(Mi.ptr + seed.len * 2, MDi_1.ptr, seed.len);
// MDi = SHA(Mi);
struct hash_context *hash = hash_alg->hash_ops->init(hash_alg,
"sha", DBG_CRYPT);
hash_alg->hash_ops->digest_bytes(hash, "msg", Mi.ptr, Mi.len);
hash_alg->hash_ops->final_bytes(&hash, seed.ptr, seed.len);
// printf("%d ", i);
// print_chunk("MDi", seed, 0);
}
print_line("");
print_number("COUNT", j);
// MDj = Seed = MD1002;
// OUTPUT: MDj; (aka seed)
print_chunk("MD", seed, 0);
}
freeanychunk(MDi_3);
freeanychunk(MDi_2);
freeanychunk(MDi_1);
freeanychunk(Mi);
print_line("");
exit(0);
}
//还是理解一下内核中的堆栈的到底是怎么一个概念，
void *kmalloc(uint32 len)
{
//申请的内存必须加上头指针，用于管理内存的空间
len += sizeof(heap_t);
heap_t * cur_head = heap_first;
heap_t * prev_head = 0;
//第一次运行的时候为0,然后运行的时候，先判断已经使用过的内存中
//有没有能用的，如果有能用的，则不用申请其他的内存使用
while (cur_head) {
if (cur_head->allocate == 0 && cur_head->length > len) {
//切分len的长度的内存出来
split_chunk(cur_head, len);
//将这个内存头指针标示为1,标示已经使用
cur_head->allocate = 1;
/*
*这个目前不是很理解
*/
return (void *) ((uint32)cur_head + sizeof(heap_t));
}
prev_head = cur_head;
cur_head = cur_head->next;
}
uint32 chunk_start;
//第一次执行，会执行else后面的代码，然后第二次初始化后执行正确的
if (prev_head) {
chunk_start = (uint32)prev_head + prev_head->length;
} else {
chunk_start = HEAP_START;
heap_first = (heap_t *)chunk_start;
}
//就是把这个线性地址和物理地址形成映射
alloc_chunk(chunk_start, len);
//描述找个内存块的相关信息
cur_head = (heap_t *) chunk_start;
//连接到上一个已经藐视内存的结构体
cur_head->prev = prev_head;
cur_head->next = 0;
cur_head->allocate = 1;
cur_head->length = len;
//将两个用过的内存块链接在一起
if (prev_head) {
prev_head->next = cur_head;
}
//申请的空间头部有heap_t这个结构体，只是描述这个内存块的信息
//所以返回的地址必须是除去这个结构体的，由于内存向上增加
return (void *)(chunk_start + sizeof(heap_t));
}
static commit_object *alloc_commit(git_revwalk *walk)
{
unsigned char *chunk;
if (walk->chunk_size == COMMITS_PER_CHUNK)
alloc_chunk(walk);
chunk = git_vector_get(&walk->memory_alloc, walk->memory_alloc.length - 1);
chunk += (walk->chunk_size * CHUNK_STEP);
walk->chunk_size++;
return (commit_object *)chunk;
}
static struct page_info * __init alloc_chunk(
struct domain *d, unsigned long max_pages)
{
static unsigned int __initdata last_order = MAX_ORDER;
static unsigned int __initdata memflags = MEMF_no_dma;
struct page_info *page;
unsigned int order = get_order_from_pages(max_pages), free_order;
if ( order > last_order )
order = last_order;
else if ( max_pages & (max_pages - 1) )
--order;
while ( (page = alloc_domheap_pages(d, order, memflags)) == NULL )
if ( order-- == 0 )
break;
if ( page )
last_order = order;
else if ( memflags )
{
/*
* Allocate up to 2MB at a time: It prevents allocating very large
* chunks from DMA pools before the >4GB pool is fully depleted.
*/
last_order = 21 - PAGE_SHIFT;
memflags = 0;
return alloc_chunk(d, max_pages);
}
/*
* Make a reasonable attempt at finding a smaller chunk at a higher
* address, to avoid allocating from low memory as much as possible.
*/
for ( free_order = order; !memflags && page && order--; )
{
struct page_info *pg2;
if ( d->tot_pages + (1 << order) > d->max_pages )
continue;
pg2 = alloc_domheap_pages(d, order, 0);
if ( pg2 > page )
{
free_domheap_pages(page, free_order);
page = pg2;
free_order = order;
}
else if ( pg2 )
free_domheap_pages(pg2, order);
}
return page;
}
void *kmalloc(uint32_t len)
{
// 所有申请的内存长度加上管理头的长度
// 因为在内存申请和释放的时候要通过该结构去管理
len += sizeof(header_t);
header_t *cur_header = heap_first;
header_t *prev_header = 0;
while (cur_header) {
// 如果当前内存块没有被申请过而且长度大于待申请的块
if (cur_header->allocated == 0 && cur_header->length >= len) {
// 按照当前长度切割内存
split_chunk(cur_header, len);
cur_header->allocated = 1;
// 返回的时候必须将指针挪到管理结构之后
return (void *)((uint32_t)cur_header + sizeof(header_t));
}
// 逐次推移指针
prev_header = cur_header;
cur_header = cur_header->next;
}
uint32_t chunk_start;
// 第一次执行该函数则初始化内存块起始位置
// 之后根据当前指针加上申请的长度即可
if (prev_header) {
chunk_start = (uint32_t)prev_header + prev_header->length;
} else {
chunk_start = HEAP_START;
heap_first = (header_t *)chunk_start;
}
// 检查是否需要申请内存页
alloc_chunk(chunk_start, len);
cur_header = (header_t *)chunk_start;
cur_header->prev = prev_header;
cur_header->next = 0;
cur_header->allocated = 1;
cur_header->length = len;
if (prev_header) {
prev_header->next = cur_header;
}
return (void*)(chunk_start + sizeof(header_t));
}
static uint8_t *
alloc_brk (struct Alloc *alloc, uint32_t needed)
{
struct AllocMmapChunk *tmp;
do {
for (tmp = alloc->chunks; tmp != 0; tmp = tmp->next)
{
if (tmp->size - tmp->brk >= needed)
{
uint8_t *buffer = tmp->buffer + tmp->brk;
tmp->brk += needed;
return buffer;
}
}
} while (alloc_chunk (alloc, alloc->default_mmap_size));
return 0;
}
static void msg_run(void)
{
print_number("Len", len);
/* byte aligned */
passert(len == (len & -4));
/* when len==0, msg may contain one byte :-/ */
passert((len == 0 && msg.len <= 1)
|| (len == msg.len * BITS_PER_BYTE));
print_chunk("Msg", msg, 0);
struct hash_context *hash = hash_alg->hash_ops->init(hash_alg, "sha", DBG_CRYPT);
/* See above, use LEN, not MSG.LEN */
hash_alg->hash_ops->digest_bytes(hash, "msg", msg.ptr, len / BITS_PER_BYTE);
chunk_t bytes = alloc_chunk(l, "bytes");
hash_alg->hash_ops->final_bytes(&hash, bytes.ptr, bytes.len);
print_chunk("MD", bytes, 0);
freeanychunk(bytes);
}
void *kmalloc(uint32_t len)
{
heap_header_t *curr, *prev;
uint32_t chunk_start;
len += sizeof(heap_header_t); // include sizeof(heap_header_t)
curr = heap_frist;
prev = 0;
while (curr) {
if (curr->allocated == 0 && curr->length >= len) {
split_chunk(curr, len);
curr->allocated = 1;
return (void *)((uint32_t)curr + sizeof(heap_header_t));
}
prev = curr;
curr = curr->next;
}
if (prev) {
chunk_start = (uint32_t)prev + prev->length;
} else {
chunk_start = HEAP_START_ADDR;
heap_frist = (heap_header_t *)chunk_start;
}
alloc_chunk(chunk_start, len);
curr = (heap_header_t *)chunk_start;
curr->prev = prev;
curr->next = 0;
curr->allocated = 1;
curr->length = len;
if (prev) {
prev->next = curr;
}
return (void *)(chunk_start + sizeof(heap_header_t));
}
void *kmalloc(uint32_t len){
len += sizeof(header_t);
header_t *cur_header = heap_first;
header_t *prev_header = 0;
while(cur_header){
if(cur_header->allocated == 0 && cur_header->length >= len){
split_chunk(cur_header, len);
cur_header->allocated = 1;
return (void *)((uint32_t)cur_header + sizeof(header_t));
}
prev_header = cur_header;
cur_header = cur_header->next;
}
uint32_t chunk_start;
if(prev_header){
chunk_start = (uint32_t)prev_header + prev_header->length;
}
else{
chunk_start = HEAP_START;
heap_first = (header_t *)chunk_start;
}
//check if need RAM
alloc_chunk(chunk_start, len);
cur_header = (header_t *)chunk_start;
cur_header->prev = prev_header;
cur_header->next = 0;
cur_header->allocated = 1;
cur_header->length = len;
if(prev_header)
prev_header->next = cur_header;
return (void*)(chunk_start + sizeof(header_t));
}
struct mcache *
mc_create(struct mcache *parent,
const char *name,
size_t size,
void (*destroy_cb)(struct mcache *, void *),
void *destroy_arg)
{
struct mcache *cache;
struct mc_chunk *chunk;
struct mc_obj *obj;
if ((chunk = alloc_chunk(size)) == NULL)
return NULL;
obj = split_obj(chunk, TAILQ_FIRST(&chunk->objs),
ALIGNOF(sizeof(*cache)));
cache = (struct mcache *) (obj->body);
cache->name = name;
cache->parent = NULL;
chunk->cache = cache;
#ifdef ENABLE_MC_DEBUG
obj->file = name;
obj->func = __func__;
obj->line = 0;
#endif
TAILQ_INIT(&cache->chunks);
TAILQ_INSERT_HEAD(&cache->chunks, chunk, node);
TAILQ_INIT(&cache->childs);
cache->chunk_num = 1;
cache->child_num = 0;
if ((cache->destroy_cb = destroy_cb) == NULL)
destroy_arg = NULL;
cache->destroy_arg = destroy_arg;
link_cache(parent, cache);
DBGTRACE("%s(%d): %s parent:%p size:%lu cache:%p\n",
__func__, __LINE__, name, parent, size, cache);
return cache;
}
SLJIT_API_FUNC_ATTRIBUTE void* sljit_malloc_exec(sljit_uw size)
{
struct block_header *header;
struct block_header *next_header;
struct free_block *free_block;
sljit_uw chunk_size;
allocator_grab_lock();
if (size < (64 - sizeof(struct block_header)))
size = (64 - sizeof(struct block_header));
size = ALIGN_SIZE(size);
free_block = free_blocks;
while (free_block) {
if (free_block->size >= size) {
chunk_size = free_block->size;
if (chunk_size > size + 64) {
/* We just cut a block from the end of the free block. */
chunk_size -= size;
free_block->size = chunk_size;
header = AS_BLOCK_HEADER(free_block, chunk_size);
header->prev_size = chunk_size;
AS_BLOCK_HEADER(header, size)->prev_size = size;
}
else {
sljit_remove_free_block(free_block);
header = (struct block_header*)free_block;
size = chunk_size;
}
allocated_size += size;
header->size = size;
allocator_release_lock();
return MEM_START(header);
}
free_block = free_block->next;
}
chunk_size = (size + sizeof(struct block_header) + CHUNK_SIZE - 1) & CHUNK_MASK;
header = (struct block_header*)alloc_chunk(chunk_size);
if (!header) {
allocator_release_lock();
return NULL;
}
chunk_size -= sizeof(struct block_header);
total_size += chunk_size;
header->prev_size = 0;
if (chunk_size > size + 64) {
/* Cut the allocated space into a free and a used block. */
allocated_size += size;
header->size = size;
chunk_size -= size;
free_block = AS_FREE_BLOCK(header, size);
free_block->header.prev_size = size;
sljit_insert_free_block(free_block, chunk_size);
next_header = AS_BLOCK_HEADER(free_block, chunk_size);
}
else {
/* All space belongs to this allocation. */
allocated_size += chunk_size;
header->size = chunk_size;
next_header = AS_BLOCK_HEADER(header, chunk_size);
}
next_header->size = 1;
next_header->prev_size = chunk_size;
allocator_release_lock();
return MEM_START(header);
}
static int
find_cache_item(unsigned rec_num,int assign_uncompressed)
{int i=cache_head,d=get_current_db_idx(),idle_item=(cache_head+1)&cache_length_mask;
if(assign_uncompressed)uncompressed=0;
if(saved_uncompressed&&cache[idle_item].chunk.d>=0
&&saved_uncompressed==cache[idle_item].content)
idle_item=(idle_item+1)&cache_length_mask;
if(facunde)
{char s[0x33];StrCopy(s,"cache find ");StrCat(s,"(");
StrIToA(s+StrLen(s),d);StrCat(s,":");
StrIToA(s+StrLen(s),rec_num);StrCat(s,")");
draw_chars(s,0,0);
}
do
{if(facunde)
{char s[0x33];StrCopy(s,"cache ");StrIToA(s+StrLen(s),i);StrCat(s,":(");
StrIToA(s+StrLen(s),cache[i].db_idx);StrCat(s,":");
StrIToA(s+StrLen(s),cache[i].rec_num);StrCat(s,");");
StrIToA(s+StrLen(s),cache[i].chunk.d);StrCat(s," ");
draw_chars(s,0,0);
}
if(cache[i].chunk.d<0){idle_item=i;goto next_i;}
if(d==cache[i].db_idx&&rec_num==cache[i].rec_num)
{if(facunde)
{char s[0x33];StrCopy(s,"found ");StrCat(s," ");
StrIToA(s+StrLen(s),i);StrCat(s,":(");
StrIToA(s+StrLen(s),d);StrCat(s,":");
StrIToA(s+StrLen(s),rec_num);StrCat(s,")");
StrIToH(s+StrLen(s),(UInt32)(cache[i].content));StrCat(s," ");
draw_chars(s,0,0);
}if(assign_uncompressed)uncompressed=cache[i].content;return i;
}
next_i:i=(i-1)&cache_length_mask;
}while(i!=cache_head);
if(facunde)
{char s[0x33];StrCopy(s,"cache loop done ");StrIToA(s+StrLen(s),idle_item);StrCat(s,":(");
StrIToA(s+StrLen(s),cache[idle_item].db_idx);StrCat(s,":");
StrIToA(s+StrLen(s),cache[idle_item].rec_num);StrCat(s,");");
StrIToA(s+StrLen(s),cache[idle_item].chunk.d);StrCat(s," ");
draw_chars(s,0,0);
}
if(cache[idle_item].chunk.d>=0)
{free_chunk(cache[idle_item].chunk);
cache[idle_item].chunk.d=invalid_chunk_descriptor;
}i=(idle_item+1)&cache_length_mask;
while(i!=idle_item)
{cache[idle_item].chunk=alloc_chunk(dh.record_size);
if(cache[idle_item].chunk.d>=0){cache_head=idle_item;break;}
while(i!=idle_item)
{int i_prev=i;i=(i+1)&cache_length_mask;
if(cache[i_prev].chunk.d>=0&&
(!saved_uncompressed||saved_uncompressed!=cache[i_prev].content))
{free_chunk(cache[i_prev].chunk);
cache[i_prev].chunk.d=invalid_chunk_descriptor;break;
}
}
}
if(facunde)
{char s[0x33];StrCopy(s,"idle alloc ");StrIToA(s+StrLen(s),idle_item);StrCat(s,":(");
StrIToA(s+StrLen(s),d);StrCat(s,":");
StrIToA(s+StrLen(s),rec_num);StrCat(s,");");
StrIToA(s+StrLen(s),cache[idle_item].chunk.d);StrCat(s," ");
draw_chars(s,0,0);
}
if(cache[idle_item].chunk.d>=0)
{if(inflate_into_chunk(cache[idle_item].chunk))
{free_chunk(cache[idle_item].chunk);
cache[idle_item].chunk.d=invalid_chunk_descriptor;
}else
{const char*uc=lock_chunk(cache[idle_item].chunk);
cache[idle_item].rec_num=rec_num;cache[idle_item].db_idx=d;
cache[idle_item].content=uc;if(assign_uncompressed)uncompressed=uc;
return idle_item;
}
}return-1;
}
/** Return a pointer to a chunk of memory in <b>area</b> of at least <b>sz</b>
* bytes. <b>sz</b> should be significantly smaller than the area's chunk
* size, though we can deal if it isn't. */
void *
memarea_alloc(memarea_t *area, size_t sz)
{
memarea_chunk_t *chunk = area->first;
char *result;
tor_assert(chunk);
CHECK_SENTINEL(chunk);
tor_assert(sz < SIZE_T_CEILING);
if (sz == 0)
sz = 1;
if (chunk->next_mem+sz > chunk->U_MEM+chunk->mem_size) {
if (sz+CHUNK_HEADER_SIZE >= CHUNK_SIZE) {
/* This allocation is too big. Stick it in a special chunk, and put
* that chunk second in the list. */
memarea_chunk_t *new_chunk = alloc_chunk(sz+CHUNK_HEADER_SIZE, 0);
new_chunk->next_chunk = chunk->next_chunk;
chunk->next_chunk = new_chunk;
chunk = new_chunk;
} else {
memarea_chunk_t *new_chunk = alloc_chunk(CHUNK_SIZE, 1);
new_chunk->next_chunk = chunk;
area->first = chunk = new_chunk;
}
tor_assert(chunk->mem_size >= sz);
}
result = chunk->next_mem;
chunk->next_mem = chunk->next_mem + sz;
/* Reinstate these if bug 930 ever comes back
tor_assert(chunk->next_mem >= chunk->U_MEM);
tor_assert(chunk->next_mem <= chunk->U_MEM+chunk->mem_size);
*/
chunk->next_mem = realign_pointer(chunk->next_mem);
return result;
}