[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 <assert.h>
#include <string.h>

#include "fio.h"
#include "fio_sem.h"
#include "os/os.h"
#include "smalloc.h"
#include "log.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	16*1024*1024	/* new pool size */
#define INITIAL_POOLS	8		/* maximum number of pools to setup */

#define MAX_POOLS	16

#define SMALLOC_PRE_RED		0xdeadbeefU
#define SMALLOC_POST_RED	0x5aa55aa5U

unsigned int smalloc_pool_size = INITIAL_SIZE;
#ifdef SMALLOC_REDZONE
static const int int_mask = sizeof(int) - 1;
#endif

struct pool {
	struct fio_sem *lock;			/* protects this pool */
	void *map;				/* map of blocks */
	unsigned int *bitmap;			/* blocks free/busy map */
	size_t free_blocks;		/* free blocks */
	size_t nr_blocks;			/* total blocks */
	size_t next_non_full;
	size_t mmap_size;
};

struct block_hdr {
	size_t 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 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 size_t size_to_blocks(size_t size)
{
	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
}

static int blocks_iter(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, size_t 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, size_t 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, size_t 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, size_t 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;
	return ffz(word) + start;
}

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

	if (nr_pools == MAX_POOLS)
		return false;

#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;

	mmap_flags = OS_MAP_ANON;
#ifdef CONFIG_ESX
	mmap_flags |= MAP_PRIVATE;
#else
	mmap_flags |= MAP_SHARED;
#endif
	ptr = mmap(NULL, alloc_size, PROT_READ|PROT_WRITE, mmap_flags, -1, 0);

	if (ptr == MAP_FAILED)
		goto out_fail;

	pool->map = ptr;
	pool->bitmap = (unsigned int *)((char *) ptr + (pool->nr_blocks * SMALLOC_BPL));
	memset(pool->bitmap, 0, bitmap_blocks * sizeof(unsigned int));

	pool->lock = fio_sem_init(FIO_SEM_UNLOCKED);
	if (!pool->lock)
		goto out_fail;

	nr_pools++;
	return true;
out_fail:
	log_err("smalloc: failed adding pool\n");
	if (pool->map)
		munmap(pool->map, pool->mmap_size);
	return false;
}

void sinit(void)
{
	bool ret;
	int i;

	for (i = 0; i < INITIAL_POOLS; i++) {
		ret = add_pool(&mp[nr_pools], smalloc_pool_size);
		if (!ret)
			break;
	}

	/*
	 * If we added at least one pool, we should be OK for most
	 * cases.
	 */
	assert(i);
}

static void cleanup_pool(struct pool *pool)
{
	/*
	 * This will also remove the temporary file we used as a backing
	 * store, it was already unlinked
	 */
	munmap(pool->map, pool->mmap_size);

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

void scleanup(void)
{
	unsigned int i;

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

#ifdef SMALLOC_REDZONE
static void *postred_ptr(struct block_hdr *hdr)
{
	uintptr_t ptr;

	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	ptr = (uintptr_t) PTR_ALIGN(ptr, 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) {
		log_err("smalloc pre redzone destroyed!\n"
			" ptr=%p, prered=%x, expected %x\n",
				hdr, hdr->prered, SMALLOC_PRE_RED);
		assert(0);
	}
	if (*postred != SMALLOC_POST_RED) {
		log_err("smalloc post redzone destroyed!\n"
			"  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;

	fio_sem_down(pool->lock);
	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);
	fio_sem_up(pool->lock);
}

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

	if (!ptr)
		return;

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

	if (pool) {
		sfree_pool(pool, ptr);
		return;
	}

	log_err("smalloc: ptr %p not from smalloc pool\n", ptr);
}

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

	fio_sem_down(pool->lock);

	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:
	fio_sem_up(pool->lock);
	return ret;
}

static void *smalloc_pool(struct pool *pool, size_t size)
{
	size_t 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(size_t size)
{
	unsigned int i, end_pool;

	if (size != (unsigned int) size)
		return NULL;

	i = last_pool;
	end_pool = nr_pools;

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

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

		break;
	} while (1);

	log_err("smalloc: OOM. Consider using --alloc-size to increase the "
		"shared memory available.\n");
	return NULL;
}

void *scalloc(size_t nmemb, size_t size)
{
	return smalloc(nmemb * size);
}

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

	ptr = smalloc(strlen(str) + 1);
	if (ptr)
		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 <assert.h>
	7	#include <string.h>
	8
	9	#include "fio.h"
	10	#include "fio_sem.h"
	11	#include "os/os.h"
	12	#include "smalloc.h"
	13	#include "log.h"
	14
	15	#define SMALLOC_REDZONE /* define to detect memory corruption */
	16
	17	#define SMALLOC_BPB 32 /* block size, bytes-per-bit in bitmap */
	18	#define SMALLOC_BPI (sizeof(unsigned int) * 8)
	19	#define SMALLOC_BPL (SMALLOC_BPB * SMALLOC_BPI)
	20
	21	#define INITIAL_SIZE 1610241024 /* new pool size */
	22	#define INITIAL_POOLS 8 /* maximum number of pools to setup */
	23
	24	#define MAX_POOLS 16
	25
	26	#define SMALLOC_PRE_RED 0xdeadbeefU
	27	#define SMALLOC_POST_RED 0x5aa55aa5U
	28
	29	unsigned int smalloc_pool_size = INITIAL_SIZE;
	30	#ifdef SMALLOC_REDZONE
	31	static const int int_mask = sizeof(int) - 1;
	32	#endif
	33
	34	struct pool {
	35	struct fio_sem lock; / protects this pool */
	36	void map; / map of blocks */
	37	unsigned int bitmap; / blocks free/busy map */
	38	size_t free_blocks; /* free blocks */
	39	size_t nr_blocks; /* total blocks */
	40	size_t next_non_full;
	41	size_t mmap_size;
	42	};
	43
	44	struct block_hdr {
	45	size_t 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
	55	static inline int ptr_valid(struct pool pool, void ptr)
	56	{
	57	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	58
	59	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	60	}
	61
	62	static inline size_t size_to_blocks(size_t size)
	63	{
	64	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	65	}
	66
	67	static int blocks_iter(struct pool *pool, unsigned int pool_idx,
	68	unsigned int idx, size_t nr_blocks,
	69	int (func)(unsigned int map, unsigned int mask))
	70	{
	71
	72	while (nr_blocks) {
	73	unsigned int this_blocks, mask;
	74	unsigned int *map;
	75
	76	if (pool_idx >= pool->nr_blocks)
	77	return 0;
	78
	79	map = &pool->bitmap[pool_idx];
	80
	81	this_blocks = nr_blocks;
	82	if (this_blocks + idx > SMALLOC_BPI) {
	83	this_blocks = SMALLOC_BPI - idx;
	84	idx = SMALLOC_BPI - this_blocks;
	85	}
	86
	87	if (this_blocks == SMALLOC_BPI)
	88	mask = -1U;
	89	else
	90	mask = ((1U << this_blocks) - 1) << idx;
	91
	92	if (!func(map, mask))
	93	return 0;
	94
	95	nr_blocks -= this_blocks;
	96	idx = 0;
	97	pool_idx++;
	98	}
	99
	100	return 1;
	101	}
	102
	103	static int mask_cmp(unsigned int *map, unsigned int mask)
	104	{
	105	return !(*map & mask);
	106	}
	107
	108	static int mask_clear(unsigned int *map, unsigned int mask)
	109	{
	110	assert((*map & mask) == mask);
	111	*map &= ~mask;
	112	return 1;
	113	}
	114
	115	static int mask_set(unsigned int *map, unsigned int mask)
	116	{
	117	assert(!(*map & mask));
	118	*map \|= mask;
	119	return 1;
	120	}
	121
	122	static int blocks_free(struct pool *pool, unsigned int pool_idx,
	123	unsigned int idx, size_t nr_blocks)
	124	{
	125	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
	126	}
	127
	128	static void set_blocks(struct pool *pool, unsigned int pool_idx,
	129	unsigned int idx, size_t nr_blocks)
	130	{
	131	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
	132	}
	133
	134	static void clear_blocks(struct pool *pool, unsigned int pool_idx,
	135	unsigned int idx, size_t nr_blocks)
	136	{
	137	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
	138	}
	139
	140	static int find_next_zero(int word, int start)
	141	{
	142	assert(word != -1U);
	143	word >>= start;
	144	return ffz(word) + start;
	145	}
	146
	147	static bool add_pool(struct pool *pool, unsigned int alloc_size)
	148	{
	149	int bitmap_blocks;
	150	int mmap_flags;
	151	void *ptr;
	152
	153	if (nr_pools == MAX_POOLS)
	154	return false;
	155
	156	#ifdef SMALLOC_REDZONE
	157	alloc_size += sizeof(unsigned int);
	158	#endif
	159	alloc_size += sizeof(struct block_hdr);
	160	if (alloc_size < INITIAL_SIZE)
	161	alloc_size = INITIAL_SIZE;
	162
	163	/* round up to nearest full number of blocks */
	164	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	165	bitmap_blocks = alloc_size / SMALLOC_BPL;
	166	alloc_size += bitmap_blocks * sizeof(unsigned int);
	167	pool->mmap_size = alloc_size;
	168
	169	pool->nr_blocks = bitmap_blocks;
	170	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
	171
	172	mmap_flags = OS_MAP_ANON;
	173	#ifdef CONFIG_ESX
	174	mmap_flags \|= MAP_PRIVATE;
	175	#else
	176	mmap_flags \|= MAP_SHARED;
	177	#endif
	178	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, mmap_flags, -1, 0);
	179
	180	if (ptr == MAP_FAILED)
	181	goto out_fail;
	182
	183	pool->map = ptr;
	184	pool->bitmap = (unsigned int )((char ) ptr + (pool->nr_blocks * SMALLOC_BPL));
	185	memset(pool->bitmap, 0, bitmap_blocks * sizeof(unsigned int));
	186
	187	pool->lock = fio_sem_init(FIO_SEM_UNLOCKED);
	188	if (!pool->lock)
	189	goto out_fail;
	190
	191	nr_pools++;
	192	return true;
	193	out_fail:
	194	log_err("smalloc: failed adding pool\n");
	195	if (pool->map)
	196	munmap(pool->map, pool->mmap_size);
	197	return false;
	198	}
	199
	200	void sinit(void)
	201	{
	202	bool ret;
	203	int i;
	204
	205	for (i = 0; i < INITIAL_POOLS; i++) {
	206	ret = add_pool(&mp[nr_pools], smalloc_pool_size);
	207	if (!ret)
	208	break;
	209	}
	210
	211	/*
	212	* If we added at least one pool, we should be OK for most
	213	* cases.
	214	*/
	215	assert(i);
	216	}
	217
	218	static void cleanup_pool(struct pool *pool)
	219	{
	220	/*
	221	* This will also remove the temporary file we used as a backing
	222	* store, it was already unlinked
	223	*/
	224	munmap(pool->map, pool->mmap_size);
	225
	226	if (pool->lock)
	227	fio_sem_remove(pool->lock);
	228	}
	229
	230	void scleanup(void)
	231	{
	232	unsigned int i;
	233
	234	for (i = 0; i < nr_pools; i++)
	235	cleanup_pool(&mp[i]);
	236	}
	237
	238	#ifdef SMALLOC_REDZONE
	239	static void postred_ptr(struct block_hdr hdr)
	240	{
	241	uintptr_t ptr;
	242
	243	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	244	ptr = (uintptr_t) PTR_ALIGN(ptr, int_mask);
	245
	246	return (void *) ptr;
	247	}
	248
	249	static void fill_redzone(struct block_hdr *hdr)
	250	{
	251	unsigned int *postred = postred_ptr(hdr);
	252
	253	hdr->prered = SMALLOC_PRE_RED;
	254	*postred = SMALLOC_POST_RED;
	255	}
	256
	257	static void sfree_check_redzone(struct block_hdr *hdr)
	258	{
	259	unsigned int *postred = postred_ptr(hdr);
	260
	261	if (hdr->prered != SMALLOC_PRE_RED) {
	262	log_err("smalloc pre redzone destroyed!\n"
	263	" ptr=%p, prered=%x, expected %x\n",
	264	hdr, hdr->prered, SMALLOC_PRE_RED);
	265	assert(0);
	266	}
	267	if (*postred != SMALLOC_POST_RED) {
	268	log_err("smalloc post redzone destroyed!\n"
	269	" ptr=%p, postred=%x, expected %x\n",
	270	hdr, *postred, SMALLOC_POST_RED);
	271	assert(0);
	272	}
	273	}
	274	#else
	275	static void fill_redzone(struct block_hdr *hdr)
	276	{
	277	}
	278
	279	static void sfree_check_redzone(struct block_hdr *hdr)
	280	{
	281	}
	282	#endif
	283
	284	static void sfree_pool(struct pool pool, void ptr)
	285	{
	286	struct block_hdr *hdr;
	287	unsigned int i, idx;
	288	unsigned long offset;
	289
	290	if (!ptr)
	291	return;
	292
	293	ptr -= sizeof(*hdr);
	294	hdr = ptr;
	295
	296	assert(ptr_valid(pool, ptr));
	297
	298	sfree_check_redzone(hdr);
	299
	300	offset = ptr - pool->map;
	301	i = offset / SMALLOC_BPL;
	302	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	303
	304	fio_sem_down(pool->lock);
	305	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	306	if (i < pool->next_non_full)
	307	pool->next_non_full = i;
	308	pool->free_blocks += size_to_blocks(hdr->size);
	309	fio_sem_up(pool->lock);
	310	}
	311
	312	void sfree(void *ptr)
	313	{
	314	struct pool *pool = NULL;
	315	unsigned int i;
	316
	317	if (!ptr)
	318	return;
	319
	320	for (i = 0; i < nr_pools; i++) {
	321	if (ptr_valid(&mp[i], ptr)) {
	322	pool = &mp[i];
	323	break;
	324	}
	325	}
	326
	327	if (pool) {
	328	sfree_pool(pool, ptr);
	329	return;
	330	}
	331
	332	log_err("smalloc: ptr %p not from smalloc pool\n", ptr);
	333	}
	334
	335	static void __smalloc_pool(struct pool pool, size_t size)
	336	{
	337	size_t nr_blocks;
	338	unsigned int i;
	339	unsigned int offset;
	340	unsigned int last_idx;
	341	void *ret = NULL;
	342
	343	fio_sem_down(pool->lock);
	344
	345	nr_blocks = size_to_blocks(size);
	346	if (nr_blocks > pool->free_blocks)
	347	goto fail;
	348
	349	i = pool->next_non_full;
	350	last_idx = 0;
	351	offset = -1U;
	352	while (i < pool->nr_blocks) {
	353	unsigned int idx;
	354
	355	if (pool->bitmap[i] == -1U) {
	356	i++;
	357	pool->next_non_full = i;
	358	last_idx = 0;
	359	continue;
	360	}
	361
	362	idx = find_next_zero(pool->bitmap[i], last_idx);
	363	if (!blocks_free(pool, i, idx, nr_blocks)) {
	364	idx += nr_blocks;
	365	if (idx < SMALLOC_BPI)
	366	last_idx = idx;
	367	else {
	368	last_idx = 0;
	369	while (idx >= SMALLOC_BPI) {
	370	i++;
	371	idx -= SMALLOC_BPI;
	372	}
	373	}
	374	continue;
	375	}
	376	set_blocks(pool, i, idx, nr_blocks);
	377	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	378	break;
	379	}
	380
	381	if (i < pool->nr_blocks) {
	382	pool->free_blocks -= nr_blocks;
	383	ret = pool->map + offset;
	384	}
	385	fail:
	386	fio_sem_up(pool->lock);
	387	return ret;
	388	}
	389
	390	static void smalloc_pool(struct pool pool, size_t size)
	391	{
	392	size_t alloc_size = size + sizeof(struct block_hdr);
	393	void *ptr;
	394
	395	/*
	396	* Round to int alignment, so that the postred pointer will
	397	* be naturally aligned as well.
	398	*/
	399	#ifdef SMALLOC_REDZONE
	400	alloc_size += sizeof(unsigned int);
	401	alloc_size = (alloc_size + int_mask) & ~int_mask;
	402	#endif
	403
	404	ptr = __smalloc_pool(pool, alloc_size);
	405	if (ptr) {
	406	struct block_hdr *hdr = ptr;
	407
	408	hdr->size = alloc_size;
	409	fill_redzone(hdr);
	410
	411	ptr += sizeof(*hdr);
	412	memset(ptr, 0, size);
	413	}
	414
	415	return ptr;
	416	}
	417
	418	void *smalloc(size_t size)
	419	{
	420	unsigned int i, end_pool;
	421
	422	if (size != (unsigned int) size)
	423	return NULL;
	424
	425	i = last_pool;
	426	end_pool = nr_pools;
	427
	428	do {
	429	for (; i < end_pool; i++) {
	430	void *ptr = smalloc_pool(&mp[i], size);
	431
	432	if (ptr) {
	433	last_pool = i;
	434	return ptr;
	435	}
	436	}
	437	if (last_pool) {
	438	end_pool = last_pool;
	439	last_pool = i = 0;
	440	continue;
	441	}
	442
	443	break;
	444	} while (1);
	445
	446	log_err("smalloc: OOM. Consider using --alloc-size to increase the "
	447	"shared memory available.\n");
	448	return NULL;
	449	}
	450
	451	void *scalloc(size_t nmemb, size_t size)
	452	{
	453	return smalloc(nmemb * size);
	454	}
	455
	456	char smalloc_strdup(const char str)
	457	{
	458	char *ptr = NULL;
	459
	460	ptr = smalloc(strlen(str) + 1);
	461	if (ptr)
	462	strcpy(ptr, str);
	463	return ptr;
	464	}