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Modified kmalloc to cater for dynamic memory allocation on a previously allocated size

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This commit is contained in:
Bahadir Balban
2009-06-01 14:48:26 +03:00
parent 33200c92df
commit 53f54f2328
1 changed files with 43 additions and 21 deletions
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64
src/generic/kmalloc.c
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@@ -11,17 +11,28 @@
/* Supports this many different kmalloc sizes */
#define KMALLOC_POOLS_MAX 5
struct kmalloc_pool_head {
struct list_head cache_list;
int occupied;
int total_caches;
int cache_size;
};
struct kmalloc_mempool {
int total;
struct list_head pool_head[KMALLOC_POOLS_MAX];
struct kmalloc_pool_head pool_head[KMALLOC_POOLS_MAX];
struct mutex kmalloc_mutex;
};
struct kmalloc_mempool km_pool;
void init_kmalloc()
{
for (int i = 0; i < KMALLOC_POOLS_MAX; i++)
INIT_LIST_HEAD(&km_pool.pool_head[i]);
for (int i = 0; i < KMALLOC_POOLS_MAX; i++) {
INIT_LIST_HEAD(&km_pool.pool_head[i].cache_list);
km_pool.pool_head[i].occupied = 0;
km_pool.pool_head[i].total_caches = 0;
km_pool.pool_head[i].cache_size = 0;
}
mutex_init(&km_pool.kmalloc_mutex);
}
@@ -33,27 +44,32 @@ void init_kmalloc()
*/
void *kmalloc(int size)
{
struct mem_cache *cache, *n;
struct mem_cache *cache;
int right_sized_pool_idx = -1;
int index;
/* Search all existing pools for this size, and if found, free bufs */
BUG_ON(!size); /* It is a kernel bug if size is 0 */
for (int i = 0; i < km_pool.total; i++) {
list_for_each_entry_safe(cache, n, &km_pool.pool_head[i], list) {
if (cache->struct_size == size) {
right_sized_pool_idx = i;
/* Check if this pool has right size */
if (km_pool.pool_head[i].cache_size == size) {
right_sized_pool_idx = i;
/*
* Found the pool, now see if any
* cache has available slots
*/
list_for_each_entry(cache, &km_pool.pool_head[i].cache_list,
list) {
if (cache->free)
return mem_cache_alloc(cache);
else
continue;
} else
break;
break;
}
}
}
/*
* No such pool list already available at hand, and we don't have room
* for new pool lists.
* All pools are allocated and none has requested size
*/
if ((right_sized_pool_idx < 0) &&
(km_pool.total == KMALLOC_POOLS_MAX - 1)) {
@@ -62,17 +78,21 @@ void *kmalloc(int size)
BUG();
}
/* A pool exists with given size? (But no cache in it is free) */
if (right_sized_pool_idx >= 0)
index = right_sized_pool_idx;
else
index = km_pool.total++;
else /* No pool of this size, allocate new by incrementing total */
index = km_pool.total++;
/* Only allow up to page size */
BUG_ON(size >= PAGE_SIZE);
BUG_ON(!(cache = mem_cache_init(alloc_page(), PAGE_SIZE,
size, 0)));
printk("%s: Created new cache for size %d\n", __FUNCTION__, size);
list_add(&cache->list, &km_pool.pool_head[index]);
list_add(&cache->list, &km_pool.pool_head[index].cache_list);
km_pool.pool_head[index].occupied = 1;
km_pool.pool_head[index].total_caches++;
km_pool.pool_head[index].cache_size = size;
return mem_cache_alloc(cache);
}
@@ -85,20 +105,22 @@ int kfree(void *p)
struct mem_cache *cache, *tmp;
for (int i = 0; i < km_pool.total; i++)
list_for_each_entry_safe(cache, tmp, &km_pool.pool_head[i], list)
list_for_each_entry_safe(cache, tmp,
&km_pool.pool_head[i].cache_list,
list) {
if (!mem_cache_free(cache, p)) {
if (mem_cache_is_empty(cache)) {
km_pool.pool_head[i].total_caches--;
list_del(&cache->list);
free_page(cache);
/*
* Total remains the same unless all
* caches are freed on that pool
* Total remains the same but slot
* may have no caches left.
*/
if (list_empty(&km_pool.pool_head[i]))
km_pool.total--;
}
return 0;
}
}
return -1;
}