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nginx-unit/src/nxt_mem_zone.c
Valentin Bartenev dfd3cc8c0e Applied nxt_pointer_to() and nxt_value_at() where possible.
2017-06-27 17:27:18 +03:00

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/*
* Copyright (C) Igor Sysoev
* Copyright (C) NGINX, Inc.
*/
#include <nxt_main.h>
#define NXT_MEM_ZONE_PAGE_FREE 0
/*
* A page was never allocated before so it should be filled with
* junk on the first time allocation if memory debugging is enabled.
*/
#define NXT_MEM_ZONE_PAGE_FRESH 1
/* An entire page is currently used, no chunks inside the page. */
#define NXT_MEM_ZONE_PAGE_USED 2
typedef struct nxt_mem_zone_page_s nxt_mem_zone_page_t;
struct nxt_mem_zone_page_s {
/*
* A size of page chunks if value is greater than or equal to 16.
* Otherwise it is used to mark page state: NXT_MEM_ZONE_PAGE_FREE,
* NXT_MEM_ZONE_PAGE_FRESH, and NXT_MEM_ZONE_PAGE_USED.
*/
uint16_t size;
/* A number of free chunks of a chunked page. */
uint16_t chunks;
union {
/* A chunk bitmap if a number of chunks is lesser than 32. */
uint8_t map[4];
/*
* The count is a number of successive occupied pages in the first
* page. In the next occupied pages and in all free pages the count
* is zero, because a number of successive free pages is stored in
* free block size resided in beginning of the first free page.
*/
uint32_t count;
} u;
/* Used for slot list of pages with free chunks. */
nxt_mem_zone_page_t *next;
/*
* Used to link of all pages including free, chunked and occupied
* pages to coalesce free pages.
*/
nxt_queue_link_t link;
};
typedef struct {
uint32_t size;
uint32_t chunks;
uint32_t start;
uint32_t map_size;
nxt_mem_zone_page_t *pages;
} nxt_mem_zone_slot_t;
typedef struct {
NXT_RBTREE_NODE (node);
uint32_t size;
} nxt_mem_zone_free_block_t;
struct nxt_mem_zone_s {
nxt_thread_spinlock_t lock;
nxt_mem_zone_page_t *pages;
nxt_mem_zone_page_t sentinel_page;
nxt_rbtree_t free_pages;
uint32_t page_size_shift;
uint32_t page_size_mask;
uint32_t max_chunk_size;
uint32_t small_bitmap_min_size;
u_char *start;
u_char *end;
nxt_mem_zone_slot_t slots[];
};
#define \
nxt_mem_zone_page_addr(zone, page) \
(void *) (zone->start + ((page - zone->pages) << zone->page_size_shift))
#define \
nxt_mem_zone_addr_page(zone, addr) \
&zone->pages[((u_char *) addr - zone->start) >> zone->page_size_shift]
#define \
nxt_mem_zone_page_is_free(page) \
(page->size < NXT_MEM_ZONE_PAGE_USED)
#define \
nxt_mem_zone_page_is_chunked(page) \
(page->size >= 16)
#define \
nxt_mem_zone_page_bitmap(zone, slot) \
(slot->size < zone->small_bitmap_min_size)
#define \
nxt_mem_zone_set_chunk_free(map, chunk) \
map[chunk / 8] &= ~(0x80 >> (chunk & 7))
#define \
nxt_mem_zone_chunk_is_free(map, chunk) \
((map[chunk / 8] & (0x80 >> (chunk & 7))) == 0)
#define \
nxt_mem_zone_fresh_junk(p, size) \
nxt_memset((p), 0xA5, size)
#define \
nxt_mem_zone_free_junk(p, size) \
nxt_memset((p), 0x5A, size)
static uint32_t nxt_mem_zone_pages(u_char *start, size_t zone_size,
nxt_uint_t page_size);
static void *nxt_mem_zone_slots_init(nxt_mem_zone_t *zone,
nxt_uint_t page_size);
static void nxt_mem_zone_slot_init(nxt_mem_zone_slot_t *slot,
nxt_uint_t page_size);
static intptr_t nxt_mem_zone_rbtree_compare(nxt_rbtree_node_t *node1,
nxt_rbtree_node_t *node2);
static void *nxt_mem_zone_alloc_small(nxt_mem_zone_t *zone,
nxt_mem_zone_slot_t *slot, size_t size);
static nxt_uint_t nxt_mem_zone_alloc_chunk(uint8_t *map, nxt_uint_t offset,
nxt_uint_t size);
static void *nxt_mem_zone_alloc_large(nxt_mem_zone_t *zone, size_t alignment,
size_t size);
static nxt_mem_zone_page_t *nxt_mem_zone_alloc_pages(nxt_mem_zone_t *zone,
size_t alignment, uint32_t pages);
static nxt_mem_zone_free_block_t *
nxt_mem_zone_find_free_block(nxt_mem_zone_t *zone, nxt_rbtree_node_t *node,
uint32_t alignment, uint32_t pages);
static const char *nxt_mem_zone_free_chunk(nxt_mem_zone_t *zone,
nxt_mem_zone_page_t *page, void *p);
static void nxt_mem_zone_free_pages(nxt_mem_zone_t *zone,
nxt_mem_zone_page_t *page, nxt_uint_t count);
static nxt_log_moderation_t nxt_mem_zone_log_moderation = {
NXT_LOG_ALERT, 2, "mem_zone_alloc() failed, not enough memory",
NXT_LOG_MODERATION
};
nxt_mem_zone_t *
nxt_mem_zone_init(u_char *start, size_t zone_size, nxt_uint_t page_size)
{
uint32_t pages;
nxt_uint_t n;
nxt_mem_zone_t *zone;
nxt_mem_zone_page_t *page;
nxt_mem_zone_free_block_t *block;
if (nxt_slow_path((page_size & (page_size - 1)) != 0)) {
nxt_thread_log_alert("mem zone page size must be a power of 2");
return NULL;
}
pages = nxt_mem_zone_pages(start, zone_size, page_size);
if (pages == 0) {
return NULL;
}
zone = (nxt_mem_zone_t *) start;
/* The function returns address after all slots. */
page = nxt_mem_zone_slots_init(zone, page_size);
zone->pages = page;
for (n = 0; n < pages; n++) {
page[n].size = NXT_MEM_ZONE_PAGE_FRESH;
}
/*
* A special sentinel page entry marked as used does not correspond
* to a real page. The entry simplifies neighbour queue nodes check
* in nxt_mem_zone_free_pages().
*/
zone->sentinel_page.size = NXT_MEM_ZONE_PAGE_USED;
nxt_queue_sentinel(&zone->sentinel_page.link);
nxt_queue_insert_after(&zone->sentinel_page.link, &page->link);
/* rbtree of free pages. */
nxt_rbtree_init(&zone->free_pages, nxt_mem_zone_rbtree_compare);
block = (nxt_mem_zone_free_block_t *) zone->start;
block->size = pages;
nxt_rbtree_insert(&zone->free_pages, &block->node);
return zone;
}
static uint32_t
nxt_mem_zone_pages(u_char *start, size_t zone_size, nxt_uint_t page_size)
{
u_char *end;
size_t reserved;
nxt_uint_t n, pages, size, chunks, last;
nxt_mem_zone_t *zone;
/*
* Find all maximum chunk sizes which zone page can be split on
* with minimum 16-byte step.
*/
last = page_size / 16;
n = 0;
size = 32;
do {
chunks = page_size / size;
if (last != chunks) {
last = chunks;
n++;
}
size += 16;
} while (chunks > 1);
/*
* Find number of usable zone pages except zone bookkeeping data,
* slots, and pages entries.
*/
reserved = sizeof(nxt_mem_zone_t) + (n * sizeof(nxt_mem_zone_slot_t));
end = nxt_trunc_ptr(start + zone_size, page_size);
zone_size = end - start;
pages = (zone_size - reserved) / (page_size + sizeof(nxt_mem_zone_page_t));
if (reserved > zone_size || pages == 0) {
nxt_thread_log_alert("mem zone size is too small: %uz", zone_size);
return 0;
}
reserved += pages * sizeof(nxt_mem_zone_page_t);
nxt_memzero(start, reserved);
zone = (nxt_mem_zone_t *) start;
zone->start = nxt_align_ptr(start + reserved, page_size);
zone->end = end;
nxt_thread_log_debug("mem zone pages: %uD, unused:%z", pages,
end - (zone->start + pages * page_size));
/*
* If a chunk size is lesser than zone->small_bitmap_min_size
* bytes, a page's chunk bitmap is larger than 32 bits and the
* bimap is placed at the start of the page.
*/
zone->small_bitmap_min_size = page_size / 32;
zone->page_size_mask = page_size - 1;
zone->max_chunk_size = page_size / 2;
n = zone->max_chunk_size;
do {
zone->page_size_shift++;
n /= 2;
} while (n != 0);
return (uint32_t) pages;
}
static void *
nxt_mem_zone_slots_init(nxt_mem_zone_t *zone, nxt_uint_t page_size)
{
nxt_uint_t n, size, chunks;
nxt_mem_zone_slot_t *slot;
slot = zone->slots;
slot[0].chunks = page_size / 16;
slot[0].size = 16;
n = 0;
size = 32;
for ( ;; ) {
chunks = page_size / size;
if (slot[n].chunks != chunks) {
nxt_mem_zone_slot_init(&slot[n], page_size);
nxt_thread_log_debug(
"mem zone size:%uD chunks:%uD start:%uD map:%uD",
slot[n].size, slot[n].chunks + 1,
slot[n].start, slot[n].map_size);
n++;
if (chunks == 1) {
return &slot[n];
}
}
slot[n].chunks = chunks;
slot[n].size = size;
size += 16;
}
}
static void
nxt_mem_zone_slot_init(nxt_mem_zone_slot_t *slot, nxt_uint_t page_size)
{
/*
* Calculate number of bytes required to store a chunk bitmap
* and align it to 4 bytes.
*/
slot->map_size = nxt_align_size(((slot->chunks + 7) / 8), 4);
/* If chunk size is not a multiple of zone page size, there
* is surplus space which can be used for the chunk's bitmap.
*/
slot->start = page_size - slot->chunks * slot->size;
/* slot->chunks should be one less than actual number of chunks. */
slot->chunks--;
if (slot->map_size > 4) {
/* A page's chunks bitmap is placed at the start of the page. */
if (slot->start < slot->map_size) {
/*
* There is no surplus space or the space is too
* small for chunks bitmap, so use the first chunks.
*/
if (slot->size < slot->map_size) {
/* The first chunks are occupied by bitmap. */
slot->chunks -= slot->map_size / slot->size;
slot->start = nxt_align_size(slot->map_size, 16);
} else {
/* The first chunk is occupied by bitmap. */
slot->chunks--;
slot->start = slot->size;
}
}
}
}
/*
* Round up to the next highest power of 2. The algorithm is
* described in "Bit Twiddling Hacks" by Sean Eron Anderson.
*/
nxt_inline uint32_t
nxt_next_highest_power_of_two(uint32_t n)
{
n--;
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
n++;
return n;
}
static intptr_t
nxt_mem_zone_rbtree_compare(nxt_rbtree_node_t *node1, nxt_rbtree_node_t *node2)
{
u_char *start1, *end1, *start2, *end2;
uint32_t n, size, size1, size2;
nxt_mem_zone_free_block_t *block1, *block2;
block1 = (nxt_mem_zone_free_block_t *) node1;
block2 = (nxt_mem_zone_free_block_t *) node2;
size1 = block1->size;
size2 = block2->size;
/*
* This subtractions do not overflow if number of pages of a free
* block is below 2^31-1. This allows to use blocks up to 128G if
* a zone page size is just 64 bytes.
*/
n = size1 - size2;
if (n != 0) {
return n;
}
/*
* Sort equally sized blocks by their capability to allocate memory with
* alignment equal to the size rounded the previous higest power of 2.
*/
/* Round the size to the previous higest power of two. */
size = nxt_next_highest_power_of_two(size1) >> 1;
/* Align the blocks' start and end to the rounded size. */
start1 = nxt_align_ptr(block1, size);
end1 = nxt_trunc_ptr((u_char *) block1 + size1, size);
start2 = nxt_align_ptr(block2, size);
end2 = nxt_trunc_ptr((u_char *) block2 + size2, size);
return (end1 - start1) - (end2 - start2);
}
void *
nxt_mem_zone_zalloc(nxt_mem_zone_t *zone, size_t size)
{
void *p;
p = nxt_mem_zone_align(zone, 1, size);
if (nxt_fast_path(p != NULL)) {
nxt_memzero(p, size);
}
return p;
}
void *
nxt_mem_zone_align(nxt_mem_zone_t *zone, size_t alignment, size_t size)
{
void *p;
nxt_mem_zone_slot_t *slot;
if (nxt_slow_path((alignment - 1) & alignment) != 0) {
/* Alignment must be a power of 2. */
return NULL;
}
if (size <= zone->max_chunk_size && alignment <= zone->max_chunk_size) {
/* All chunks are aligned to 16. */
if (alignment > 16) {
/*
* Chunks which size is power of 2 are aligned to the size.
* So allocation size should be increased to the next highest
* power of two. This can waste memory, but a main consumer
* of aligned allocations is lvlhsh which anyway allocates
* memory with alignment equal to size.
*/
size = nxt_next_highest_power_of_two(size);
size = nxt_max(size, alignment);
}
/*
* Find a zone slot with appropriate chunk size.
* This operation can be performed without holding lock.
*/
for (slot = zone->slots; slot->size < size; slot++) { /* void */ }
nxt_thread_log_debug("mem zone alloc: @%uz:%uz chunk:%uD",
alignment, size, slot->size);
nxt_thread_spin_lock(&zone->lock);
p = nxt_mem_zone_alloc_small(zone, slot, size);
} else {
nxt_thread_log_debug("mem zone alloc: @%uz:%uz", alignment, size);
nxt_thread_spin_lock(&zone->lock);
p = nxt_mem_zone_alloc_large(zone, alignment, size);
}
nxt_thread_spin_unlock(&zone->lock);
if (nxt_fast_path(p != NULL)) {
nxt_thread_log_debug("mem zone alloc: %p", p);
} else {
nxt_log_moderate(&nxt_mem_zone_log_moderation,
NXT_LOG_ALERT, nxt_thread_log(),
"nxt_mem_zone_alloc(%uz, %uz) failed, not enough memory",
alignment, size);
}
return p;
}
static void *
nxt_mem_zone_alloc_small(nxt_mem_zone_t *zone, nxt_mem_zone_slot_t *slot,
size_t size)
{
u_char *p;
uint8_t *map;
nxt_mem_zone_page_t *page;
page = slot->pages;
if (nxt_fast_path(page != NULL)) {
p = nxt_mem_zone_page_addr(zone, page);
if (nxt_mem_zone_page_bitmap(zone, slot)) {
/* A page's chunks bitmap is placed at the start of the page. */
map = p;
} else {
map = page->u.map;
}
p += nxt_mem_zone_alloc_chunk(map, slot->start, slot->size);
page->chunks--;
if (page->chunks == 0) {
/*
* Remove full page from the zone slot list of pages with
* free chunks.
*/
slot->pages = page->next;
#if (NXT_DEBUG)
page->next = NULL;
#endif
}
return p;
}
page = nxt_mem_zone_alloc_pages(zone, 1, 1);
if (nxt_fast_path(page != NULL)) {
slot->pages = page;
page->size = slot->size;
/* slot->chunks are already one less. */
page->chunks = slot->chunks;
page->u.count = 0;
page->next = NULL;
p = nxt_mem_zone_page_addr(zone, page);
if (nxt_mem_zone_page_bitmap(zone, slot)) {
/* A page's chunks bitmap is placed at the start of the page. */
map = p;
nxt_memzero(map, slot->map_size);
} else {
map = page->u.map;
}
/* Mark the first chunk as busy. */
map[0] = 0x80;
return p + slot->start;
}
return NULL;
}
static nxt_uint_t
nxt_mem_zone_alloc_chunk(uint8_t *map, nxt_uint_t offset, nxt_uint_t size)
{
uint8_t mask;
nxt_uint_t n;
n = 0;
/* The page must have at least one free chunk. */
for ( ;; ) {
/* The bitmap is always aligned to uint32_t. */
if (*(uint32_t *) &map[n] != 0xffffffff) {
do {
if (map[n] != 0xff) {
mask = 0x80;
do {
if ((map[n] & mask) == 0) {
/* The free chunk is found. */
map[n] |= mask;
return offset;
}
offset += size;
mask >>= 1;
} while (mask != 0);
} else {
/* Fast-forward: all 8 chunks are occupied. */
offset += size * 8;
}
n++;
} while (n % 4 != 0);
} else {
/* Fast-forward: all 32 chunks are occupied. */
offset += size * 32;
n += 4;
}
}
}
static void *
nxt_mem_zone_alloc_large(nxt_mem_zone_t *zone, size_t alignment, size_t size)
{
uint32_t pages;
nxt_mem_zone_page_t *page;
pages = (size + zone->page_size_mask) >> zone->page_size_shift;
page = nxt_mem_zone_alloc_pages(zone, alignment, pages);
if (nxt_fast_path(page != NULL)) {
return nxt_mem_zone_page_addr(zone, page);
}
return NULL;
}
static nxt_mem_zone_page_t *
nxt_mem_zone_alloc_pages(nxt_mem_zone_t *zone, size_t alignment, uint32_t pages)
{
u_char *p;
size_t prev_size;
uint32_t prev_pages, node_pages, next_pages;
nxt_uint_t n;
nxt_mem_zone_page_t *prev_page, *page, *next_page;
nxt_mem_zone_free_block_t *block, *next_block;
block = nxt_mem_zone_find_free_block(zone,
nxt_rbtree_root(&zone->free_pages),
alignment, pages);
if (nxt_slow_path(block == NULL)) {
return NULL;
}
node_pages = block->size;
nxt_rbtree_delete(&zone->free_pages, &block->node);
p = nxt_align_ptr(block, alignment);
page = nxt_mem_zone_addr_page(zone, p);
prev_size = p - (u_char *) block;
if (prev_size != 0) {
prev_pages = prev_size >>= zone->page_size_shift;
node_pages -= prev_pages;
block->size = prev_pages;
nxt_rbtree_insert(&zone->free_pages, &block->node);
prev_page = nxt_mem_zone_addr_page(zone, block);
nxt_queue_insert_after(&prev_page->link, &page->link);
}
next_pages = node_pages - pages;
if (next_pages != 0) {
next_page = &page[pages];
next_block = nxt_mem_zone_page_addr(zone, next_page);
next_block->size = next_pages;
nxt_rbtree_insert(&zone->free_pages, &next_block->node);
nxt_queue_insert_after(&page->link, &next_page->link);
}
/* Go through pages after all rbtree operations to not trash CPU cache. */
page[0].u.count = pages;
for (n = 0; n < pages; n++) {
if (page[n].size == NXT_MEM_ZONE_PAGE_FRESH) {
nxt_mem_zone_fresh_junk(nxt_mem_zone_page_addr(zone, &page[n]),
zone->page_size_mask + 1);
}
page[n].size = NXT_MEM_ZONE_PAGE_USED;
}
return page;
}
/*
* Free blocks are sorted by size and then if the sizes are equal
* by aligned allocation capabilty. The former criterion is just
* comparison with a requested size and it can be used for iteractive
* search. The later criterion cannot be tested only by the requested
* size and alignment, so recursive in-order tree traversal is required
* to find a suitable free block. nxt_mem_zone_find_free_block() uses
* only recursive in-order tree traversal because anyway the slowest part
* of the algorithm are CPU cache misses. Besides the last tail recursive
* call may be optimized by compiler into iteractive search.
*/
static nxt_mem_zone_free_block_t *
nxt_mem_zone_find_free_block(nxt_mem_zone_t *zone, nxt_rbtree_node_t *node,
uint32_t alignment, uint32_t pages)
{
u_char *aligned, *end;
nxt_mem_zone_free_block_t *block, *free_block;
if (node == nxt_rbtree_sentinel(&zone->free_pages)) {
return NULL;
}
block = (nxt_mem_zone_free_block_t *) node;
if (pages <= block->size) {
free_block = nxt_mem_zone_find_free_block(zone, block->node.left,
alignment, pages);
if (free_block != NULL) {
return free_block;
}
aligned = nxt_align_ptr(block, alignment);
if (pages == block->size) {
if (aligned == (u_char *) block) {
/* Exact match. */
return block;
}
} else { /* pages < block->size */
aligned += pages << zone->page_size_shift;
end = nxt_pointer_to(block, block->size << zone->page_size_shift);
if (aligned <= end) {
return block;
}
}
}
return nxt_mem_zone_find_free_block(zone, block->node.right,
alignment, pages);
}
void
nxt_mem_zone_free(nxt_mem_zone_t *zone, void *p)
{
nxt_uint_t count;
const char *err;
nxt_mem_zone_page_t *page;
nxt_thread_log_debug("mem zone free: %p", p);
if (nxt_fast_path(zone->start <= (u_char *) p
&& (u_char *) p < zone->end))
{
page = nxt_mem_zone_addr_page(zone, p);
nxt_thread_spin_lock(&zone->lock);
if (nxt_mem_zone_page_is_chunked(page)) {
err = nxt_mem_zone_free_chunk(zone, page, p);
} else if (nxt_slow_path(nxt_mem_zone_page_is_free(page))) {
err = "page is already free";
} else if (nxt_slow_path((uintptr_t) p & zone->page_size_mask) != 0) {
err = "invalid pointer to chunk";
} else {
count = page->u.count;
if (nxt_fast_path(count != 0)) {
nxt_mem_zone_free_junk(p, count * zone->page_size_mask + 1);
nxt_mem_zone_free_pages(zone, page, count);
err = NULL;
} else {
/* Not the first allocated page. */
err = "pointer to wrong page";
}
}
nxt_thread_spin_unlock(&zone->lock);
} else {
err = "pointer is out of zone";
}
if (nxt_slow_path(err != NULL)) {
nxt_thread_log_alert("nxt_mem_zone_free(%p): %s", p, err);
}
}
static const char *
nxt_mem_zone_free_chunk(nxt_mem_zone_t *zone, nxt_mem_zone_page_t *page,
void *p)
{
u_char *map;
uint32_t size, offset, chunk;
nxt_mem_zone_page_t *pg, **ppg;
nxt_mem_zone_slot_t *slot;
size = page->size;
/* Find a zone slot with appropriate chunk size. */
for (slot = zone->slots; slot->size < size; slot++) { /* void */ }
offset = (uintptr_t) p & zone->page_size_mask;
offset -= slot->start;
chunk = offset / size;
if (nxt_slow_path(offset != chunk * size)) {
return "pointer to wrong chunk";
}
if (nxt_mem_zone_page_bitmap(zone, slot)) {
/* A page's chunks bitmap is placed at the start of the page. */
map = (u_char *) ((uintptr_t) p & ~((uintptr_t) zone->page_size_mask));
} else {
map = page->u.map;
}
if (nxt_mem_zone_chunk_is_free(map, chunk)) {
return "chunk is already free";
}
nxt_mem_zone_set_chunk_free(map, chunk);
nxt_mem_zone_free_junk(p, page->size);
if (page->chunks == 0) {
page->chunks = 1;
/* Add the page to the head of slot list of pages with free chunks. */
page->next = slot->pages;
slot->pages = page;
} else if (page->chunks != slot->chunks) {
page->chunks++;
} else {
if (map != page->u.map) {
nxt_mem_zone_free_junk(map, slot->map_size);
}
/*
* All chunks are free, remove the page from the slot list of pages
* with free chunks and add the page to the free pages tree.
*/
ppg = &slot->pages;
for (pg = slot->pages; pg != NULL; pg = pg->next) {
if (pg == page) {
*ppg = page->next;
break;
}
ppg = &pg->next;
}
nxt_mem_zone_free_pages(zone, page, 1);
}
return NULL;
}
static void
nxt_mem_zone_free_pages(nxt_mem_zone_t *zone, nxt_mem_zone_page_t *page,
nxt_uint_t count)
{
nxt_mem_zone_page_t *prev_page, *next_page;
nxt_mem_zone_free_block_t *block, *prev_block, *next_block;
page->size = NXT_MEM_ZONE_PAGE_FREE;
page->chunks = 0;
page->u.count = 0;
page->next = NULL;
nxt_memzero(&page[1], (count - 1) * sizeof(nxt_mem_zone_page_t));
next_page = nxt_queue_link_data(page->link.next, nxt_mem_zone_page_t, link);
if (nxt_mem_zone_page_is_free(next_page)) {
/* Coalesce with the next free pages. */
nxt_queue_remove(&next_page->link);
nxt_memzero(next_page, sizeof(nxt_mem_zone_page_t));
next_block = nxt_mem_zone_page_addr(zone, next_page);
count += next_block->size;
nxt_rbtree_delete(&zone->free_pages, &next_block->node);
}
prev_page = nxt_queue_link_data(page->link.prev, nxt_mem_zone_page_t, link);
if (nxt_mem_zone_page_is_free(prev_page)) {
/* Coalesce with the previous free pages. */
nxt_queue_remove(&page->link);
prev_block = nxt_mem_zone_page_addr(zone, prev_page);
count += prev_block->size;
nxt_rbtree_delete(&zone->free_pages, &prev_block->node);
prev_block->size = count;
nxt_rbtree_insert(&zone->free_pages, &prev_block->node);
return;
}
block = nxt_mem_zone_page_addr(zone, page);
block->size = count;
nxt_rbtree_insert(&zone->free_pages, &block->node);
}
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