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/*
* Copyright 2010 Marek Olšák <maraeo@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "util/u_slab.h"
#include "util/u_math.h"
#include "util/u_memory.h"
#include "util/u_simple_list.h"
#include <stdio.h>
#define UTIL_SLAB_MAGIC 0xcafe4321
/* The block is either allocated memory or free space. */
struct util_slab_block {
/* The header. */
/* The first next free block. */
struct util_slab_block *next_free;
intptr_t magic;
/* Memory after the last member is dedicated to the block itself.
* The allocated size is always larger than this structure. */
};
static struct util_slab_block *
util_slab_get_block(struct util_slab_mempool *pool,
struct util_slab_page *page, unsigned index)
{
return (struct util_slab_block*)
((uint8_t*)page + sizeof(struct util_slab_page) +
(pool->block_size * index));
}
static void util_slab_add_new_page(struct util_slab_mempool *pool)
{
struct util_slab_page *page;
struct util_slab_block *block;
unsigned i;
page = MALLOC(pool->page_size);
insert_at_tail(&pool->list, page);
/* Mark all blocks as free. */
for (i = 0; i < pool->num_blocks-1; i++) {
block = util_slab_get_block(pool, page, i);
block->next_free = util_slab_get_block(pool, page, i+1);
block->magic = UTIL_SLAB_MAGIC;
}
block = util_slab_get_block(pool, page, pool->num_blocks-1);
block->next_free = pool->first_free;
block->magic = UTIL_SLAB_MAGIC;
pool->first_free = util_slab_get_block(pool, page, 0);
pool->num_pages++;
#if 0
fprintf(stderr, "New page! Num of pages: %i\n", pool->num_pages);
#endif
}
static void *util_slab_alloc_st(struct util_slab_mempool *pool)
{
struct util_slab_block *block;
if (!pool->first_free)
util_slab_add_new_page(pool);
block = pool->first_free;
assert(block->magic == UTIL_SLAB_MAGIC);
pool->first_free = block->next_free;
return (uint8_t*)block + sizeof(struct util_slab_block);
}
static void util_slab_free_st(struct util_slab_mempool *pool, void *ptr)
{
struct util_slab_block *block =
(struct util_slab_block*)
((uint8_t*)ptr - sizeof(struct util_slab_block));
assert(block->magic == UTIL_SLAB_MAGIC);
block->next_free = pool->first_free;
pool->first_free = block;
}
static void *util_slab_alloc_mt(struct util_slab_mempool *pool)
{
void *mem;
pipe_mutex_lock(pool->mutex);
mem = util_slab_alloc_st(pool);
pipe_mutex_unlock(pool->mutex);
return mem;
}
static void util_slab_free_mt(struct util_slab_mempool *pool, void *ptr)
{
pipe_mutex_lock(pool->mutex);
util_slab_free_st(pool, ptr);
pipe_mutex_unlock(pool->mutex);
}
void util_slab_set_thread_safety(struct util_slab_mempool *pool,
enum util_slab_threading threading)
{
pool->threading = threading;
if (threading) {
pool->alloc = util_slab_alloc_mt;
pool->free = util_slab_free_mt;
} else {
pool->alloc = util_slab_alloc_st;
pool->free = util_slab_free_st;
}
}
void util_slab_create(struct util_slab_mempool *pool,
unsigned item_size,
unsigned num_blocks,
enum util_slab_threading threading)
{
item_size = align(item_size, sizeof(intptr_t));
pool->num_pages = 0;
pool->num_blocks = num_blocks;
pool->block_size = sizeof(struct util_slab_block) + item_size;
pool->block_size = align(pool->block_size, sizeof(intptr_t));
pool->page_size = sizeof(struct util_slab_page) +
num_blocks * pool->block_size;
pool->first_free = NULL;
make_empty_list(&pool->list);
pipe_mutex_init(pool->mutex);
util_slab_set_thread_safety(pool, threading);
}
void util_slab_destroy(struct util_slab_mempool *pool)
{
struct util_slab_page *page, *temp;
if (pool->list.next) {
foreach_s(page, temp, &pool->list) {
remove_from_list(page);
FREE(page);
}
}
pipe_mutex_destroy(pool->mutex);
}
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