[fio.git] / smalloc.c

/*
 * simple memory allocator, backed by mmap() so that it hands out memory
 * that can be shared across processes and threads
 */
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <limits.h>

#include "mutex.h"

#define MP_SAFE			/* define to make thread safe */
#define SMALLOC_REDZONE		/* define to detect memory corruption */

#define SMALLOC_BPB	32	/* block size, bytes-per-bit in bitmap */
#define SMALLOC_BPI	(sizeof(unsigned int) * 8)
#define SMALLOC_BPL	(SMALLOC_BPB * SMALLOC_BPI)

#define INITIAL_SIZE	1024*1024	/* new pool size */
#define MAX_POOLS	4		/* maximum number of pools to setup */

#define SMALLOC_PRE_RED		0xdeadbeefU
#define SMALLOC_POST_RED	0x5aa55aa5U

unsigned int smalloc_pool_size = INITIAL_SIZE;

struct pool {
	struct fio_mutex *lock;			/* protects this pool */
	void *map;				/* map of blocks */
	unsigned int *bitmap;			/* blocks free/busy map */
	unsigned int free_blocks;		/* free blocks */
	unsigned int nr_blocks;			/* total blocks */
	unsigned int next_non_full;
	int fd;					/* memory backing fd */
	char file[PATH_MAX];			/* filename for fd */
	unsigned int mmap_size;
};

struct block_hdr {
	unsigned int size;
#ifdef SMALLOC_REDZONE
	unsigned int prered;
#endif
};

static struct pool mp[MAX_POOLS];
static unsigned int nr_pools;
static unsigned int last_pool;
static struct fio_mutex *lock;

static inline void pool_lock(struct pool *pool)
{
	if (pool->lock)
		fio_mutex_down(pool->lock);
}

static inline void pool_unlock(struct pool *pool)
{
	if (pool->lock)
		fio_mutex_up(pool->lock);
}

static inline void global_read_lock(void)
{
	if (lock)
		fio_mutex_down_read(lock);
}

static inline void global_read_unlock(void)
{
	if (lock)
		fio_mutex_up_read(lock);
}

static inline void global_write_lock(void)
{
	if (lock)
		fio_mutex_down_write(lock);
}

static inline void global_write_unlock(void)
{
	if (lock)
		fio_mutex_up_write(lock);
}

static inline int ptr_valid(struct pool *pool, void *ptr)
{
	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;

	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
}

static int blocks_iter(unsigned int *map, unsigned int idx,
		       unsigned int nr_blocks,
		       int (*func)(unsigned int *map, unsigned int mask))
{
	while (nr_blocks) {
		unsigned int this_blocks, mask;

		this_blocks = nr_blocks;
		if (this_blocks + idx > SMALLOC_BPI) {
			this_blocks = SMALLOC_BPI - idx;
			idx = SMALLOC_BPI - this_blocks;
		}

		if (this_blocks == SMALLOC_BPI)
			mask = -1U;
		else
			mask = ((1U << this_blocks) - 1) << idx;

		if (!func(map, mask))
			return 0;

		nr_blocks -= this_blocks;
		idx = 0;
		map++;
	}

	return 1;

}

static int mask_cmp(unsigned int *map, unsigned int mask)
{
	return !(*map & mask);
}

static int mask_clear(unsigned int *map, unsigned int mask)
{
	*map &= ~mask;
	return 1;
}

static int mask_set(unsigned int *map, unsigned int mask)
{
	*map |= mask;
	return 1;
}

static int blocks_free(unsigned int *map, unsigned int idx,
		       unsigned int nr_blocks)
{
	return blocks_iter(map, idx, nr_blocks, mask_cmp);
}

static void set_blocks(unsigned int *map, unsigned int idx,
		       unsigned int nr_blocks)
{
	blocks_iter(map, idx, nr_blocks, mask_set);
}

static void clear_blocks(unsigned int *map, unsigned int idx,
			 unsigned int nr_blocks)
{
	blocks_iter(map, idx, nr_blocks, mask_clear);
}

static inline int __ffs(int word)
{
	int r = 0;

	if (!(word & 0xffff)) {
		word >>= 16;
		r += 16;
	}
	if (!(word & 0xff)) {
		word >>= 8;
		r += 8;
	}
	if (!(word & 0xf)) {
		word >>= 4;
		r += 4;
	}
	if (!(word & 3)) {
		word >>= 2;
		r += 2;
	}
	if (!(word & 1)) {
		word >>= 1;
		r += 1;
	}

	return r;
}

static int find_next_zero(int word, int start)
{
	assert(word != -1U);
	word >>= (start + 1);
	return __ffs(~word) + start + 1;
}

static int add_pool(struct pool *pool, unsigned int alloc_size)
{
	void *ptr;
	int fd, bitmap_blocks;

	printf("add pool %u\n", alloc_size);

	strcpy(pool->file, "/tmp/.fio_smalloc.XXXXXX");
	fd = mkstemp(pool->file);
	if (fd < 0)
		goto out_close;

#ifdef SMALLOC_REDZONE
	alloc_size += sizeof(unsigned int);
#endif
	alloc_size += sizeof(struct block_hdr);
	if (alloc_size < INITIAL_SIZE)
		alloc_size = INITIAL_SIZE;

	/* round up to nearest full number of blocks */
	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	bitmap_blocks = alloc_size / SMALLOC_BPL;
	alloc_size += bitmap_blocks * sizeof(unsigned int);
	pool->mmap_size = alloc_size;
	
	pool->nr_blocks = bitmap_blocks;
	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;

	if (ftruncate(fd, alloc_size) < 0)
		goto out_unlink;

	ptr = mmap(NULL, alloc_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	if (ptr == MAP_FAILED)
		goto out_unlink;

	memset(ptr, 0, alloc_size);
	pool->map = ptr;
	pool->bitmap = (void *) ptr + (pool->nr_blocks * SMALLOC_BPL);

#ifdef MP_SAFE
	pool->lock = fio_mutex_init(1);
	if (!pool->lock)
		goto out_unlink;
#endif

	pool->fd = fd;

	global_write_lock();
	nr_pools++;
	global_write_unlock();
	return 0;
out_unlink:
	fprintf(stderr, "smalloc: failed adding pool\n");
	if (pool->map)
		munmap(pool->map, pool->mmap_size);
	unlink(pool->file);
out_close:
	if (fd >= 0)
		close(fd);
	return 1;
}

void sinit(void)
{
	int ret;

#ifdef MP_SAFE
	lock = fio_mutex_rw_init();
#endif
	ret = add_pool(&mp[0], INITIAL_SIZE);
	assert(!ret);
}

static void cleanup_pool(struct pool *pool)
{
	unlink(pool->file);
	close(pool->fd);
	munmap(pool->map, pool->mmap_size);

	if (pool->lock)
		fio_mutex_remove(pool->lock);
}

void scleanup(void)
{
	unsigned int i;

	for (i = 0; i < nr_pools; i++)
		cleanup_pool(&mp[i]);

	if (lock)
		fio_mutex_remove(lock);
}

static void fill_redzone(struct block_hdr *hdr)
{
#ifdef SMALLOC_REDZONE
	unsigned int *postred = (void *) hdr + hdr->size - sizeof(unsigned int);

	hdr->prered = SMALLOC_PRE_RED;
	*postred = SMALLOC_POST_RED;
#endif
}

static void sfree_check_redzone(struct block_hdr *hdr)
{
#ifdef SMALLOC_REDZONE
	unsigned int *postred = (void *) hdr + hdr->size - sizeof(unsigned int);

	if (hdr->prered != SMALLOC_PRE_RED) {
		fprintf(stderr, "smalloc pre redzone destroyed!\n");
		fprintf(stderr, "  ptr=%p, prered=%x, expected %x\n",
				hdr, hdr->prered, SMALLOC_PRE_RED);
		assert(0);
	}
	if (*postred != SMALLOC_POST_RED) {
		fprintf(stderr, "smalloc post redzone destroyed!\n");
		fprintf(stderr, "  ptr=%p, postred=%x, expected %x\n",
				hdr, *postred, SMALLOC_POST_RED);
		assert(0);
	}
#endif
}

static void sfree_pool(struct pool *pool, void *ptr)
{
	struct block_hdr *hdr;
	unsigned int nr_blocks, i, idx;
	unsigned long offset;

	if (!ptr)
		return;

	ptr -= sizeof(*hdr);
	hdr = ptr;

	assert(ptr_valid(pool, ptr));

	nr_blocks = (hdr->size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	sfree_check_redzone(hdr);

	offset = ptr - pool->map;
	i = offset / SMALLOC_BPL;
	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;

	pool_lock(pool);
	clear_blocks(&pool->bitmap[i], idx, nr_blocks);
	if (i < pool->next_non_full)
		pool->next_non_full = i;
	pool->free_blocks += nr_blocks;
	pool_unlock(pool);
}

void sfree(void *ptr)
{
	struct pool *pool = NULL;
	unsigned int i;

	if (!ptr)
		return;

	global_read_lock();

	for (i = 0; i < nr_pools; i++) {
		if (ptr_valid(&mp[i], ptr)) {
			pool = &mp[i];
			break;
		}
	}

	global_read_unlock();

	assert(pool);
	sfree_pool(pool, ptr);
}

static void *__smalloc_pool(struct pool *pool, unsigned int size)
{
	unsigned int nr_blocks;
	unsigned int i;
	unsigned int offset;
	unsigned int last_idx;
	void *ret = NULL;

	nr_blocks = (size + SMALLOC_BPB - 1) / SMALLOC_BPB;

	pool_lock(pool);
	if (nr_blocks > pool->free_blocks)
		goto fail;

	i = pool->next_non_full;
	last_idx = 0;
	offset = -1U;
	while (i < pool->nr_blocks) {
		unsigned int idx;

		if (pool->bitmap[i] == -1U) {
			i++;
			pool->next_non_full = i;
			last_idx = 0;
			continue;
		}

		idx = find_next_zero(pool->bitmap[i], last_idx);
		if (!blocks_free(&pool->bitmap[i], idx, nr_blocks)) {
			idx += nr_blocks;
			if (idx < SMALLOC_BPI)
				last_idx = idx;
			else {
				last_idx = 0;
				while (idx >= SMALLOC_BPI) {
					i++;
					idx -= SMALLOC_BPI;
				}
			}
			continue;
		}
		set_blocks(&pool->bitmap[i], idx, nr_blocks);
		offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
		break;
	}

	if (i < pool->nr_blocks) {
		pool->free_blocks -= nr_blocks;
		ret = pool->map + offset;
	}
fail:
	pool_unlock(pool);
	return ret;
}

static void *smalloc_pool(struct pool *pool, unsigned int size)
{
	struct block_hdr *hdr;
	unsigned int alloc_size;
	void *ptr;

	alloc_size = size + sizeof(*hdr);
#ifdef SMALLOC_REDZONE
	alloc_size += sizeof(unsigned int);
#endif

	ptr = __smalloc_pool(pool, alloc_size);
	if (!ptr) {
		printf("failed allocating %u\n", alloc_size);
		return NULL;
	}

	hdr = ptr;
	hdr->size = alloc_size;
	ptr += sizeof(*hdr);

	fill_redzone(hdr);

	memset(ptr, 0, size);
	return ptr;
}

void *smalloc(unsigned int size)
{
	unsigned int i;

	global_read_lock();
	i = last_pool;

	do {
		for (; i < nr_pools; i++) {
			void *ptr = smalloc_pool(&mp[i], size);

			if (ptr) {
				last_pool = i;
				global_read_unlock();
				return ptr;
			}
		}
		if (last_pool) {
			last_pool = 0;
			continue;
		}

		if (nr_pools + 1 > MAX_POOLS)
			break;
		else {
			i = nr_pools;
			global_read_unlock();
			if (add_pool(&mp[nr_pools], size))
				goto out;
			global_read_lock();
		}
	} while (1);

	global_read_unlock();
out:
	return NULL;
}

char *smalloc_strdup(const char *str)
{
	char *ptr;

	ptr = smalloc(strlen(str) + 1);
	strcpy(ptr, str);
	return ptr;
}
Commit	Line	Data
	1	/*
	2	* simple memory allocator, backed by mmap() so that it hands out memory
	3	* that can be shared across processes and threads
	4	*/
	5	#include <sys/mman.h>
	6	#include <stdio.h>
	7	#include <stdlib.h>
	8	#include <assert.h>
	9	#include <string.h>
	10	#include <unistd.h>
	11	#include <sys/types.h>
	12	#include <limits.h>
	13
	14	#include "mutex.h"
	15
	16	#define MP_SAFE /* define to make thread safe */
	17	#define SMALLOC_REDZONE /* define to detect memory corruption */
	18
	19	#define SMALLOC_BPB 32 /* block size, bytes-per-bit in bitmap */
	20	#define SMALLOC_BPI (sizeof(unsigned int) * 8)
	21	#define SMALLOC_BPL (SMALLOC_BPB * SMALLOC_BPI)
	22
	23	#define INITIAL_SIZE 10241024 / new pool size */
	24	#define MAX_POOLS 4 /* maximum number of pools to setup */
	25
	26	#define SMALLOC_PRE_RED 0xdeadbeefU
	27	#define SMALLOC_POST_RED 0x5aa55aa5U
	28
	29	unsigned int smalloc_pool_size = INITIAL_SIZE;
	30
	31	struct pool {
	32	struct fio_mutex lock; / protects this pool */
	33	void map; / map of blocks */
	34	unsigned int bitmap; / blocks free/busy map */
	35	unsigned int free_blocks; /* free blocks */
	36	unsigned int nr_blocks; /* total blocks */
	37	unsigned int next_non_full;
	38	int fd; /* memory backing fd */
	39	char file[PATH_MAX]; /* filename for fd */
	40	unsigned int mmap_size;
	41	};
	42
	43	struct block_hdr {
	44	unsigned int size;
	45	#ifdef SMALLOC_REDZONE
	46	unsigned int prered;
	47	#endif
	48	};
	49
	50	static struct pool mp[MAX_POOLS];
	51	static unsigned int nr_pools;
	52	static unsigned int last_pool;
	53	static struct fio_mutex *lock;
	54
	55	static inline void pool_lock(struct pool *pool)
	56	{
	57	if (pool->lock)
	58	fio_mutex_down(pool->lock);
	59	}
	60
	61	static inline void pool_unlock(struct pool *pool)
	62	{
	63	if (pool->lock)
	64	fio_mutex_up(pool->lock);
	65	}
	66
	67	static inline void global_read_lock(void)
	68	{
	69	if (lock)
	70	fio_mutex_down_read(lock);
	71	}
	72
	73	static inline void global_read_unlock(void)
	74	{
	75	if (lock)
	76	fio_mutex_up_read(lock);
	77	}
	78
	79	static inline void global_write_lock(void)
	80	{
	81	if (lock)
	82	fio_mutex_down_write(lock);
	83	}
	84
	85	static inline void global_write_unlock(void)
	86	{
	87	if (lock)
	88	fio_mutex_up_write(lock);
	89	}
	90
	91	static inline int ptr_valid(struct pool pool, void ptr)
	92	{
	93	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	94
	95	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	96	}
	97
	98	static int blocks_iter(unsigned int *map, unsigned int idx,
	99	unsigned int nr_blocks,
	100	int (func)(unsigned int map, unsigned int mask))
	101	{
	102	while (nr_blocks) {
	103	unsigned int this_blocks, mask;
	104
	105	this_blocks = nr_blocks;
	106	if (this_blocks + idx > SMALLOC_BPI) {
	107	this_blocks = SMALLOC_BPI - idx;
	108	idx = SMALLOC_BPI - this_blocks;
	109	}
	110
	111	if (this_blocks == SMALLOC_BPI)
	112	mask = -1U;
	113	else
	114	mask = ((1U << this_blocks) - 1) << idx;
	115
	116	if (!func(map, mask))
	117	return 0;
	118
	119	nr_blocks -= this_blocks;
	120	idx = 0;
	121	map++;
	122	}
	123
	124	return 1;
	125
	126	}
	127
	128	static int mask_cmp(unsigned int *map, unsigned int mask)
	129	{
	130	return !(*map & mask);
	131	}
	132
	133	static int mask_clear(unsigned int *map, unsigned int mask)
	134	{
	135	*map &= ~mask;
	136	return 1;
	137	}
	138
	139	static int mask_set(unsigned int *map, unsigned int mask)
	140	{
	141	*map \|= mask;
	142	return 1;
	143	}
	144
	145	static int blocks_free(unsigned int *map, unsigned int idx,
	146	unsigned int nr_blocks)
	147	{
	148	return blocks_iter(map, idx, nr_blocks, mask_cmp);
	149	}
	150
	151	static void set_blocks(unsigned int *map, unsigned int idx,
	152	unsigned int nr_blocks)
	153	{
	154	blocks_iter(map, idx, nr_blocks, mask_set);
	155	}
	156
	157	static void clear_blocks(unsigned int *map, unsigned int idx,
	158	unsigned int nr_blocks)
	159	{
	160	blocks_iter(map, idx, nr_blocks, mask_clear);
	161	}
	162
	163	static inline int __ffs(int word)
	164	{
	165	int r = 0;
	166
	167	if (!(word & 0xffff)) {
	168	word >>= 16;
	169	r += 16;
	170	}
	171	if (!(word & 0xff)) {
	172	word >>= 8;
	173	r += 8;
	174	}
	175	if (!(word & 0xf)) {
	176	word >>= 4;
	177	r += 4;
	178	}
	179	if (!(word & 3)) {
	180	word >>= 2;
	181	r += 2;
	182	}
	183	if (!(word & 1)) {
	184	word >>= 1;
	185	r += 1;
	186	}
	187
	188	return r;
	189	}
	190
	191	static int find_next_zero(int word, int start)
	192	{
	193	assert(word != -1U);
	194	word >>= (start + 1);
	195	return __ffs(~word) + start + 1;
	196	}
	197
	198	static int add_pool(struct pool *pool, unsigned int alloc_size)
	199	{
	200	void *ptr;
	201	int fd, bitmap_blocks;
	202
	203	printf("add pool %u\n", alloc_size);
	204
	205	strcpy(pool->file, "/tmp/.fio_smalloc.XXXXXX");
	206	fd = mkstemp(pool->file);
	207	if (fd < 0)
	208	goto out_close;
	209
	210	#ifdef SMALLOC_REDZONE
	211	alloc_size += sizeof(unsigned int);
	212	#endif
	213	alloc_size += sizeof(struct block_hdr);
	214	if (alloc_size < INITIAL_SIZE)
	215	alloc_size = INITIAL_SIZE;
	216
	217	/* round up to nearest full number of blocks */
	218	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	219	bitmap_blocks = alloc_size / SMALLOC_BPL;
	220	alloc_size += bitmap_blocks * sizeof(unsigned int);
	221	pool->mmap_size = alloc_size;
	222
	223	pool->nr_blocks = bitmap_blocks;
	224	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
	225
	226	if (ftruncate(fd, alloc_size) < 0)
	227	goto out_unlink;
	228
	229	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, MAP_SHARED, fd, 0);
	230	if (ptr == MAP_FAILED)
	231	goto out_unlink;
	232
	233	memset(ptr, 0, alloc_size);
	234	pool->map = ptr;
	235	pool->bitmap = (void ) ptr + (pool->nr_blocks SMALLOC_BPL);
	236
	237	#ifdef MP_SAFE
	238	pool->lock = fio_mutex_init(1);
	239	if (!pool->lock)
	240	goto out_unlink;
	241	#endif
	242
	243	pool->fd = fd;
	244
	245	global_write_lock();
	246	nr_pools++;
	247	global_write_unlock();
	248	return 0;
	249	out_unlink:
	250	fprintf(stderr, "smalloc: failed adding pool\n");
	251	if (pool->map)
	252	munmap(pool->map, pool->mmap_size);
	253	unlink(pool->file);
	254	out_close:
	255	if (fd >= 0)
	256	close(fd);
	257	return 1;
	258	}
	259
	260	void sinit(void)
	261	{
	262	int ret;
	263
	264	#ifdef MP_SAFE
	265	lock = fio_mutex_rw_init();
	266	#endif
	267	ret = add_pool(&mp[0], INITIAL_SIZE);
	268	assert(!ret);
	269	}
	270
	271	static void cleanup_pool(struct pool *pool)
	272	{
	273	unlink(pool->file);
	274	close(pool->fd);
	275	munmap(pool->map, pool->mmap_size);
	276
	277	if (pool->lock)
	278	fio_mutex_remove(pool->lock);
	279	}
	280
	281	void scleanup(void)
	282	{
	283	unsigned int i;
	284
	285	for (i = 0; i < nr_pools; i++)
	286	cleanup_pool(&mp[i]);
	287
	288	if (lock)
	289	fio_mutex_remove(lock);
	290	}
	291
	292	static void fill_redzone(struct block_hdr *hdr)
	293	{
	294	#ifdef SMALLOC_REDZONE
	295	unsigned int postred = (void ) hdr + hdr->size - sizeof(unsigned int);
	296
	297	hdr->prered = SMALLOC_PRE_RED;
	298	*postred = SMALLOC_POST_RED;
	299	#endif
	300	}
	301
	302	static void sfree_check_redzone(struct block_hdr *hdr)
	303	{
	304	#ifdef SMALLOC_REDZONE
	305	unsigned int postred = (void ) hdr + hdr->size - sizeof(unsigned int);
	306
	307	if (hdr->prered != SMALLOC_PRE_RED) {
	308	fprintf(stderr, "smalloc pre redzone destroyed!\n");
	309	fprintf(stderr, " ptr=%p, prered=%x, expected %x\n",
	310	hdr, hdr->prered, SMALLOC_PRE_RED);
	311	assert(0);
	312	}
	313	if (*postred != SMALLOC_POST_RED) {
	314	fprintf(stderr, "smalloc post redzone destroyed!\n");
	315	fprintf(stderr, " ptr=%p, postred=%x, expected %x\n",
	316	hdr, *postred, SMALLOC_POST_RED);
	317	assert(0);
	318	}
	319	#endif
	320	}
	321
	322	static void sfree_pool(struct pool pool, void ptr)
	323	{
	324	struct block_hdr *hdr;
	325	unsigned int nr_blocks, i, idx;
	326	unsigned long offset;
	327
	328	if (!ptr)
	329	return;
	330
	331	ptr -= sizeof(*hdr);
	332	hdr = ptr;
	333
	334	assert(ptr_valid(pool, ptr));
	335
	336	nr_blocks = (hdr->size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	337	sfree_check_redzone(hdr);
	338
	339	offset = ptr - pool->map;
	340	i = offset / SMALLOC_BPL;
	341	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	342
	343	pool_lock(pool);
	344	clear_blocks(&pool->bitmap[i], idx, nr_blocks);
	345	if (i < pool->next_non_full)
	346	pool->next_non_full = i;
	347	pool->free_blocks += nr_blocks;
	348	pool_unlock(pool);
	349	}
	350
	351	void sfree(void *ptr)
	352	{
	353	struct pool *pool = NULL;
	354	unsigned int i;
	355
	356	if (!ptr)
	357	return;
	358
	359	global_read_lock();
	360
	361	for (i = 0; i < nr_pools; i++) {
	362	if (ptr_valid(&mp[i], ptr)) {
	363	pool = &mp[i];
	364	break;
	365	}
	366	}
	367
	368	global_read_unlock();
	369
	370	assert(pool);
	371	sfree_pool(pool, ptr);
	372	}
	373
	374	static void __smalloc_pool(struct pool pool, unsigned int size)
	375	{
	376	unsigned int nr_blocks;
	377	unsigned int i;
	378	unsigned int offset;
	379	unsigned int last_idx;
	380	void *ret = NULL;
	381
	382	nr_blocks = (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	383
	384	pool_lock(pool);
	385	if (nr_blocks > pool->free_blocks)
	386	goto fail;
	387
	388	i = pool->next_non_full;
	389	last_idx = 0;
	390	offset = -1U;
	391	while (i < pool->nr_blocks) {
	392	unsigned int idx;
	393
	394	if (pool->bitmap[i] == -1U) {
	395	i++;
	396	pool->next_non_full = i;
	397	last_idx = 0;
	398	continue;
	399	}
	400
	401	idx = find_next_zero(pool->bitmap[i], last_idx);
	402	if (!blocks_free(&pool->bitmap[i], idx, nr_blocks)) {
	403	idx += nr_blocks;
	404	if (idx < SMALLOC_BPI)
	405	last_idx = idx;
	406	else {
	407	last_idx = 0;
	408	while (idx >= SMALLOC_BPI) {
	409	i++;
	410	idx -= SMALLOC_BPI;
	411	}
	412	}
	413	continue;
	414	}
	415	set_blocks(&pool->bitmap[i], idx, nr_blocks);
	416	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	417	break;
	418	}
	419
	420	if (i < pool->nr_blocks) {
	421	pool->free_blocks -= nr_blocks;
	422	ret = pool->map + offset;
	423	}
	424	fail:
	425	pool_unlock(pool);
	426	return ret;
	427	}
	428
	429	static void smalloc_pool(struct pool pool, unsigned int size)
	430	{
	431	struct block_hdr *hdr;
	432	unsigned int alloc_size;
	433	void *ptr;
	434
	435	alloc_size = size + sizeof(*hdr);
	436	#ifdef SMALLOC_REDZONE
	437	alloc_size += sizeof(unsigned int);
	438	#endif
	439
	440	ptr = __smalloc_pool(pool, alloc_size);
	441	if (!ptr) {
	442	printf("failed allocating %u\n", alloc_size);
	443	return NULL;
	444	}
	445
	446	hdr = ptr;
	447	hdr->size = alloc_size;
	448	ptr += sizeof(*hdr);
	449
	450	fill_redzone(hdr);
	451
	452	memset(ptr, 0, size);
	453	return ptr;
	454	}
	455
	456	void *smalloc(unsigned int size)
	457	{
	458	unsigned int i;
	459
	460	global_read_lock();
	461	i = last_pool;
	462
	463	do {
	464	for (; i < nr_pools; i++) {
	465	void *ptr = smalloc_pool(&mp[i], size);
	466
	467	if (ptr) {
	468	last_pool = i;
	469	global_read_unlock();
	470	return ptr;
	471	}
	472	}
	473	if (last_pool) {
	474	last_pool = 0;
	475	continue;
	476	}
	477
	478	if (nr_pools + 1 > MAX_POOLS)
	479	break;
	480	else {
	481	i = nr_pools;
	482	global_read_unlock();
	483	if (add_pool(&mp[nr_pools], size))
	484	goto out;
	485	global_read_lock();
	486	}
	487	} while (1);
	488
	489	global_read_unlock();
	490	out:
	491	return NULL;
	492	}
	493
	494	char smalloc_strdup(const char str)
	495	{
	496	char *ptr;
	497
	498	ptr = smalloc(strlen(str) + 1);
	499	strcpy(ptr, str);
	500	return ptr;
	501	}