[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 <fcntl.h>

#include "mutex.h"
#include "arch/arch.h"
#include "os/os.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	8192*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;
const int int_mask = sizeof(int) - 1;

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;

#ifdef FIO_HAVE_FALLOCATE
	{
		int ret;

		ret = posix_fallocate(fd, 0, alloc_size);
		if (ret > 0) {
			fprintf(stderr, "posix_fallocate pool file failed: %s\n", strerror(ret));
			goto out_unlink;
		}
	}
#endif

	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 *postred_ptr(struct block_hdr *hdr)
{
	unsigned long ptr;

	ptr = (unsigned long) hdr + hdr->size - sizeof(unsigned int);
	ptr = (ptr + int_mask) & ~int_mask;

	return (void *) ptr;
}

static void fill_redzone(struct block_hdr *hdr)
{
	unsigned int *postred = postred_ptr(hdr);

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

static void sfree_check_redzone(struct block_hdr *hdr)
{
	unsigned int *postred = postred_ptr(hdr);

	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;

	/*
	 * Round to int alignment, so that the postred pointer will
	 * be naturally aligned as well.
	 */
#ifdef SMALLOC_REDZONE
	alloc_size += sizeof(unsigned int);
	alloc_size = (alloc_size + int_mask) & ~int_mask;
#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	#include <fcntl.h>
	14
	15	#include "mutex.h"
	16	#include "arch/arch.h"
	17	#include "os/os.h"
	18
	19	#define SMALLOC_REDZONE /* define to detect memory corruption */
	20
	21	#define SMALLOC_BPB 32 /* block size, bytes-per-bit in bitmap */
	22	#define SMALLOC_BPI (sizeof(unsigned int) * 8)
	23	#define SMALLOC_BPL (SMALLOC_BPB * SMALLOC_BPI)
	24
	25	#define INITIAL_SIZE 81921024 / new pool size */
	26	#define MAX_POOLS 128 /* maximum number of pools to setup */
	27
	28	#define SMALLOC_PRE_RED 0xdeadbeefU
	29	#define SMALLOC_POST_RED 0x5aa55aa5U
	30
	31	unsigned int smalloc_pool_size = INITIAL_SIZE;
	32	const int int_mask = sizeof(int) - 1;
	33
	34	struct pool {
	35	struct fio_mutex lock; / protects this pool */
	36	void map; / map of blocks */
	37	unsigned int bitmap; / blocks free/busy map */
	38	unsigned int free_blocks; /* free blocks */
	39	unsigned int nr_blocks; /* total blocks */
	40	unsigned int next_non_full;
	41	int fd; /* memory backing fd */
	42	unsigned int mmap_size;
	43	};
	44
	45	struct block_hdr {
	46	unsigned int size;
	47	#ifdef SMALLOC_REDZONE
	48	unsigned int prered;
	49	#endif
	50	};
	51
	52	static struct pool mp[MAX_POOLS];
	53	static unsigned int nr_pools;
	54	static unsigned int last_pool;
	55	static struct fio_mutex *lock;
	56
	57	static inline void pool_lock(struct pool *pool)
	58	{
	59	fio_mutex_down(pool->lock);
	60	}
	61
	62	static inline void pool_unlock(struct pool *pool)
	63	{
	64	fio_mutex_up(pool->lock);
	65	}
	66
	67	static inline void global_read_lock(void)
	68	{
	69	fio_mutex_down_read(lock);
	70	}
	71
	72	static inline void global_read_unlock(void)
	73	{
	74	fio_mutex_up_read(lock);
	75	}
	76
	77	static inline void global_write_lock(void)
	78	{
	79	fio_mutex_down_write(lock);
	80	}
	81
	82	static inline void global_write_unlock(void)
	83	{
	84	fio_mutex_up_write(lock);
	85	}
	86
	87	static inline int ptr_valid(struct pool pool, void ptr)
	88	{
	89	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	90
	91	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	92	}
	93
	94	static inline unsigned int size_to_blocks(unsigned int size)
	95	{
	96	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	97	}
	98
	99	static int blocks_iter(struct pool *pool, unsigned int pool_idx,
	100	unsigned int idx, unsigned int nr_blocks,
	101	int (func)(unsigned int map, unsigned int mask))
	102	{
	103
	104	while (nr_blocks) {
	105	unsigned int this_blocks, mask;
	106	unsigned int *map;
	107
	108	if (pool_idx >= pool->nr_blocks)
	109	return 0;
	110
	111	map = &pool->bitmap[pool_idx];
	112
	113	this_blocks = nr_blocks;
	114	if (this_blocks + idx > SMALLOC_BPI) {
	115	this_blocks = SMALLOC_BPI - idx;
	116	idx = SMALLOC_BPI - this_blocks;
	117	}
	118
	119	if (this_blocks == SMALLOC_BPI)
	120	mask = -1U;
	121	else
	122	mask = ((1U << this_blocks) - 1) << idx;
	123
	124	if (!func(map, mask))
	125	return 0;
	126
	127	nr_blocks -= this_blocks;
	128	idx = 0;
	129	pool_idx++;
	130	}
	131
	132	return 1;
	133	}
	134
	135	static int mask_cmp(unsigned int *map, unsigned int mask)
	136	{
	137	return !(*map & mask);
	138	}
	139
	140	static int mask_clear(unsigned int *map, unsigned int mask)
	141	{
	142	assert((*map & mask) == mask);
	143	*map &= ~mask;
	144	return 1;
	145	}
	146
	147	static int mask_set(unsigned int *map, unsigned int mask)
	148	{
	149	assert(!(*map & mask));
	150	*map \|= mask;
	151	return 1;
	152	}
	153
	154	static int blocks_free(struct pool *pool, unsigned int pool_idx,
	155	unsigned int idx, unsigned int nr_blocks)
	156	{
	157	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
	158	}
	159
	160	static void set_blocks(struct pool *pool, unsigned int pool_idx,
	161	unsigned int idx, unsigned int nr_blocks)
	162	{
	163	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
	164	}
	165
	166	static void clear_blocks(struct pool *pool, unsigned int pool_idx,
	167	unsigned int idx, unsigned int nr_blocks)
	168	{
	169	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
	170	}
	171
	172	static int find_next_zero(int word, int start)
	173	{
	174	assert(word != -1U);
	175	word >>= (start + 1);
	176	return ffz(word) + start + 1;
	177	}
	178
	179	static int add_pool(struct pool *pool, unsigned int alloc_size)
	180	{
	181	int fd, bitmap_blocks;
	182	char file[] = "/tmp/.fio_smalloc.XXXXXX";
	183	void *ptr;
	184
	185	fd = mkstemp(file);
	186	if (fd < 0)
	187	goto out_close;
	188
	189	#ifdef SMALLOC_REDZONE
	190	alloc_size += sizeof(unsigned int);
	191	#endif
	192	alloc_size += sizeof(struct block_hdr);
	193	if (alloc_size < INITIAL_SIZE)
	194	alloc_size = INITIAL_SIZE;
	195
	196	/* round up to nearest full number of blocks */
	197	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	198	bitmap_blocks = alloc_size / SMALLOC_BPL;
	199	alloc_size += bitmap_blocks * sizeof(unsigned int);
	200	pool->mmap_size = alloc_size;
	201
	202	pool->nr_blocks = bitmap_blocks;
	203	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
	204
	205	#ifdef FIO_HAVE_FALLOCATE
	206	{
	207	int ret;
	208
	209	ret = posix_fallocate(fd, 0, alloc_size);
	210	if (ret > 0) {
	211	fprintf(stderr, "posix_fallocate pool file failed: %s\n", strerror(ret));
	212	goto out_unlink;
	213	}
	214	}
	215	#endif
	216
	217	if (ftruncate(fd, alloc_size) < 0)
	218	goto out_unlink;
	219
	220	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, MAP_SHARED, fd, 0);
	221	if (ptr == MAP_FAILED)
	222	goto out_unlink;
	223
	224	memset(ptr, 0, alloc_size);
	225	pool->map = ptr;
	226	pool->bitmap = (void ) ptr + (pool->nr_blocks SMALLOC_BPL);
	227
	228	pool->lock = fio_mutex_init(1);
	229	if (!pool->lock)
	230	goto out_unlink;
	231
	232	/*
	233	* Unlink pool file now. It wont get deleted until the fd is closed,
	234	* which happens both for cleanup or unexpected quit. This way we
	235	* don't leave temp files around in case of a crash.
	236	*/
	237	unlink(file);
	238	pool->fd = fd;
	239
	240	nr_pools++;
	241	return 0;
	242	out_unlink:
	243	fprintf(stderr, "smalloc: failed adding pool\n");
	244	if (pool->map)
	245	munmap(pool->map, pool->mmap_size);
	246	unlink(file);
	247	out_close:
	248	close(fd);
	249	return 1;
	250	}
	251
	252	void sinit(void)
	253	{
	254	int ret;
	255
	256	lock = fio_mutex_rw_init();
	257	ret = add_pool(&mp[0], INITIAL_SIZE);
	258	assert(!ret);
	259	}
	260
	261	static void cleanup_pool(struct pool *pool)
	262	{
	263	/*
	264	* This will also remove the temporary file we used as a backing
	265	* store, it was already unlinked
	266	*/
	267	close(pool->fd);
	268	munmap(pool->map, pool->mmap_size);
	269
	270	if (pool->lock)
	271	fio_mutex_remove(pool->lock);
	272	}
	273
	274	void scleanup(void)
	275	{
	276	unsigned int i;
	277
	278	for (i = 0; i < nr_pools; i++)
	279	cleanup_pool(&mp[i]);
	280
	281	if (lock)
	282	fio_mutex_remove(lock);
	283	}
	284
	285	#ifdef SMALLOC_REDZONE
	286	static void postred_ptr(struct block_hdr hdr)
	287	{
	288	unsigned long ptr;
	289
	290	ptr = (unsigned long) hdr + hdr->size - sizeof(unsigned int);
	291	ptr = (ptr + int_mask) & ~int_mask;
	292
	293	return (void *) ptr;
	294	}
	295
	296	static void fill_redzone(struct block_hdr *hdr)
	297	{
	298	unsigned int *postred = postred_ptr(hdr);
	299
	300	hdr->prered = SMALLOC_PRE_RED;
	301	*postred = SMALLOC_POST_RED;
	302	}
	303
	304	static void sfree_check_redzone(struct block_hdr *hdr)
	305	{
	306	unsigned int *postred = postred_ptr(hdr);
	307
	308	if (hdr->prered != SMALLOC_PRE_RED) {
	309	fprintf(stderr, "smalloc pre redzone destroyed!\n");
	310	fprintf(stderr, " ptr=%p, prered=%x, expected %x\n",
	311	hdr, hdr->prered, SMALLOC_PRE_RED);
	312	assert(0);
	313	}
	314	if (*postred != SMALLOC_POST_RED) {
	315	fprintf(stderr, "smalloc post redzone destroyed!\n");
	316	fprintf(stderr, " ptr=%p, postred=%x, expected %x\n",
	317	hdr, *postred, SMALLOC_POST_RED);
	318	assert(0);
	319	}
	320	}
	321	#else
	322	static void fill_redzone(struct block_hdr *hdr)
	323	{
	324	}
	325
	326	static void sfree_check_redzone(struct block_hdr *hdr)
	327	{
	328	}
	329	#endif
	330
	331	static void sfree_pool(struct pool pool, void ptr)
	332	{
	333	struct block_hdr *hdr;
	334	unsigned int i, idx;
	335	unsigned long offset;
	336
	337	if (!ptr)
	338	return;
	339
	340	ptr -= sizeof(*hdr);
	341	hdr = ptr;
	342
	343	assert(ptr_valid(pool, ptr));
	344
	345	sfree_check_redzone(hdr);
	346
	347	offset = ptr - pool->map;
	348	i = offset / SMALLOC_BPL;
	349	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	350
	351	pool_lock(pool);
	352	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	353	if (i < pool->next_non_full)
	354	pool->next_non_full = i;
	355	pool->free_blocks += size_to_blocks(hdr->size);
	356	pool_unlock(pool);
	357	}
	358
	359	void sfree(void *ptr)
	360	{
	361	struct pool *pool = NULL;
	362	unsigned int i;
	363
	364	if (!ptr)
	365	return;
	366
	367	global_read_lock();
	368
	369	for (i = 0; i < nr_pools; i++) {
	370	if (ptr_valid(&mp[i], ptr)) {
	371	pool = &mp[i];
	372	break;
	373	}
	374	}
	375
	376	global_read_unlock();
	377
	378	assert(pool);
	379	sfree_pool(pool, ptr);
	380	}
	381
	382	static void __smalloc_pool(struct pool pool, unsigned int size)
	383	{
	384	unsigned int nr_blocks;
	385	unsigned int i;
	386	unsigned int offset;
	387	unsigned int last_idx;
	388	void *ret = NULL;
	389
	390	pool_lock(pool);
	391
	392	nr_blocks = size_to_blocks(size);
	393	if (nr_blocks > pool->free_blocks)
	394	goto fail;
	395
	396	i = pool->next_non_full;
	397	last_idx = 0;
	398	offset = -1U;
	399	while (i < pool->nr_blocks) {
	400	unsigned int idx;
	401
	402	if (pool->bitmap[i] == -1U) {
	403	i++;
	404	pool->next_non_full = i;
	405	last_idx = 0;
	406	continue;
	407	}
	408
	409	idx = find_next_zero(pool->bitmap[i], last_idx);
	410	if (!blocks_free(pool, i, idx, nr_blocks)) {
	411	idx += nr_blocks;
	412	if (idx < SMALLOC_BPI)
	413	last_idx = idx;
	414	else {
	415	last_idx = 0;
	416	while (idx >= SMALLOC_BPI) {
	417	i++;
	418	idx -= SMALLOC_BPI;
	419	}
	420	}
	421	continue;
	422	}
	423	set_blocks(pool, i, idx, nr_blocks);
	424	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	425	break;
	426	}
	427
	428	if (i < pool->nr_blocks) {
	429	pool->free_blocks -= nr_blocks;
	430	ret = pool->map + offset;
	431	}
	432	fail:
	433	pool_unlock(pool);
	434	return ret;
	435	}
	436
	437	static void smalloc_pool(struct pool pool, unsigned int size)
	438	{
	439	unsigned int alloc_size = size + sizeof(struct block_hdr);
	440	void *ptr;
	441
	442	/*
	443	* Round to int alignment, so that the postred pointer will
	444	* be naturally aligned as well.
	445	*/
	446	#ifdef SMALLOC_REDZONE
	447	alloc_size += sizeof(unsigned int);
	448	alloc_size = (alloc_size + int_mask) & ~int_mask;
	449	#endif
	450
	451	ptr = __smalloc_pool(pool, alloc_size);
	452	if (ptr) {
	453	struct block_hdr *hdr = ptr;
	454
	455	hdr->size = alloc_size;
	456	fill_redzone(hdr);
	457
	458	ptr += sizeof(*hdr);
	459	memset(ptr, 0, size);
	460	}
	461
	462	return ptr;
	463	}
	464
	465	void *smalloc(unsigned int size)
	466	{
	467	unsigned int i;
	468
	469	global_write_lock();
	470	i = last_pool;
	471
	472	do {
	473	for (; i < nr_pools; i++) {
	474	void *ptr = smalloc_pool(&mp[i], size);
	475
	476	if (ptr) {
	477	last_pool = i;
	478	global_write_unlock();
	479	return ptr;
	480	}
	481	}
	482	if (last_pool) {
	483	last_pool = 0;
	484	continue;
	485	}
	486
	487	if (nr_pools + 1 > MAX_POOLS)
	488	break;
	489	else {
	490	i = nr_pools;
	491	if (add_pool(&mp[nr_pools], size))
	492	goto out;
	493	}
	494	} while (1);
	495
	496	out:
	497	global_write_unlock();
	498	return NULL;
	499	}
	500
	501	char smalloc_strdup(const char str)
	502	{
	503	char *ptr;
	504
	505	ptr = smalloc(strlen(str) + 1);
	506	strcpy(ptr, str);
	507	return ptr;
	508	}