[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 "arch/arch.h"

#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	128		/* 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 */
	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)
{
	fio_mutex_down(pool->lock);
}

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

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

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

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

static inline void global_write_unlock(void)
{
	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 ffz(word) + start + 1;
}

static int add_pool(struct pool *pool, unsigned int alloc_size)
{
	int fd, bitmap_blocks;
	char file[] = "/tmp/.fio_smalloc.XXXXXX";
	void *ptr;

	fd = mkstemp(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);

	pool->lock = fio_mutex_init(1);
	if (!pool->lock)
		goto out_unlink;

	/*
	 * Unlink pool file now. It wont get deleted until the fd is closed,
	 * which happens both for cleanup or unexpected quit. This way we
	 * don't leave temp files around in case of a crash.
	 */
	unlink(file);
	pool->fd = fd;

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

void sinit(void)
{
	int ret;

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

static void cleanup_pool(struct pool *pool)
{
	/*
	 * This will also remove the temporary file we used as a backing
	 * store, it was already unlinked
	 */
	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_write_lock();
	i = last_pool;

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

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

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

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