[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"
#include "lib/ffz.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 inline unsigned int size_to_blocks(unsigned int size)
{
	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
}

static int blocks_iter(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, unsigned int nr_blocks,
		       int (*func)(unsigned int *map, unsigned int mask))
{

	while (nr_blocks) {
		unsigned int this_blocks, mask;
		unsigned int *map;

		if (pool_idx >= pool->nr_blocks)
			return 0;

		map = &pool->bitmap[pool_idx];

		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;
		pool_idx++;
	}

	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)
{
	assert((*map & mask) == mask);
	*map &= ~mask;
	return 1;
}

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

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

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

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

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;

	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);
}

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

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

static void sfree_check_redzone(struct block_hdr *hdr)
{
	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);
	}
}
#else
static void fill_redzone(struct block_hdr *hdr)
{
}

static void sfree_check_redzone(struct block_hdr *hdr)
{
}
#endif

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

	if (!ptr)
		return;

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

	assert(ptr_valid(pool, ptr));

	sfree_check_redzone(hdr);

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

	pool_lock(pool);
	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	if (i < pool->next_non_full)
		pool->next_non_full = i;
	pool->free_blocks += size_to_blocks(hdr->size);
	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;

	pool_lock(pool);

	nr_blocks = size_to_blocks(size);
	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, 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, 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)
{
	unsigned int alloc_size = size + sizeof(struct block_hdr);
	void *ptr;

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

	ptr = __smalloc_pool(pool, alloc_size);
	if (ptr) {
		struct block_hdr *hdr = ptr;

		hdr->size = alloc_size;
		fill_redzone(hdr);

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