mempool: add API for malloc semantics

This works like k_malloc() but allows the user to designate
a specific memory pool to use instead of the kernel heap.

Test coverage provided by existing tests for k_malloc(), which is
now derived from this API.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2018-04-12 16:59:02 -07:00 committed by Andrew Boie
commit a2480bd472
3 changed files with 56 additions and 33 deletions

View file

@ -151,10 +151,15 @@ since that is the closest matching size supported by the memory pool.
printf("Memory allocation time-out");
}
Memory blocks may also be allocated with :cpp:func:`malloc()`-like semantics
using :cpp:func:`k_mem_pool_malloc()`. Such allocations must be freed with
:cpp:func:`k_free()`.
Releasing a Memory Block
========================
A memory block is released by calling :cpp:func:`k_mem_pool_free()`.
A memory block is released by calling either :cpp:func:`k_mem_pool_free()`
or :cpp:func:`k_free()`, depending on how it was allocated.
The following code builds on the example above, and allocates a 75 byte
memory block, then releases it once it is no longer needed. (A 256 byte
@ -184,3 +189,5 @@ The following memory pool APIs are provided by :file:`kernel.h`:
* :c:macro:`K_MEM_POOL_DEFINE`
* :cpp:func:`k_mem_pool_alloc()`
* :cpp:func:`k_mem_pool_free()`
* :cpp:func:`k_mem_pool_malloc()`
* :cpp:func:`k_free()`

View file

@ -3652,6 +3652,17 @@ struct k_mem_pool {
extern int k_mem_pool_alloc(struct k_mem_pool *pool, struct k_mem_block *block,
size_t size, s32_t timeout);
/**
* @brief Allocate memory from a memory pool with malloc() semantics
*
* Such memory must be released using k_free().
*
* @param pool Address of the memory pool.
* @param size Amount of memory to allocate (in bytes).
* @return Address of the allocated memory if successful, otherwise NULL
*/
extern void *k_mem_pool_malloc(struct k_mem_pool *pool, size_t size);
/**
* @brief Free memory allocated from a memory pool.
*
@ -3702,7 +3713,8 @@ extern void *k_malloc(size_t size);
* @brief Free memory allocated from heap.
*
* This routine provides traditional free() semantics. The memory being
* returned must have been allocated from the heap memory pool.
* returned must have been allocated from the heap memory pool or
* k_mem_pool_malloc().
*
* If @a ptr is NULL, no operation is performed.
*

View file

@ -119,6 +119,40 @@ void k_mem_pool_free(struct k_mem_block *block)
k_mem_pool_free_id(&block->id);
}
void *k_mem_pool_malloc(struct k_mem_pool *pool, size_t size)
{
struct k_mem_block block;
/*
* get a block large enough to hold an initial (hidden) block
* descriptor, as well as the space the caller requested
*/
if (__builtin_add_overflow(size, sizeof(struct k_mem_block_id),
&size)) {
return NULL;
}
if (k_mem_pool_alloc(pool, &block, size, K_NO_WAIT) != 0) {
return NULL;
}
/* save the block descriptor info at the start of the actual block */
memcpy(block.data, &block.id, sizeof(struct k_mem_block_id));
/* return address of the user area part of the block to the caller */
return (char *)block.data + sizeof(struct k_mem_block_id);
}
void k_free(void *ptr)
{
if (ptr != NULL) {
/* point to hidden block descriptor at start of block */
ptr = (char *)ptr - sizeof(struct k_mem_block_id);
/* return block to the heap memory pool */
k_mem_pool_free_id(ptr);
}
}
#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
/*
@ -133,37 +167,7 @@ K_MEM_POOL_DEFINE(_heap_mem_pool, 64, CONFIG_HEAP_MEM_POOL_SIZE, 1, 4);
void *k_malloc(size_t size)
{
struct k_mem_block block;
/*
* get a block large enough to hold an initial (hidden) block
* descriptor, as well as the space the caller requested
*/
if (__builtin_add_overflow(size, sizeof(struct k_mem_block_id),
&size)) {
return NULL;
}
if (k_mem_pool_alloc(_HEAP_MEM_POOL, &block, size, K_NO_WAIT) != 0) {
return NULL;
}
/* save the block descriptor info at the start of the actual block */
memcpy(block.data, &block.id, sizeof(struct k_mem_block_id));
/* return address of the user area part of the block to the caller */
return (char *)block.data + sizeof(struct k_mem_block_id);
}
void k_free(void *ptr)
{
if (ptr != NULL) {
/* point to hidden block descriptor at start of block */
ptr = (char *)ptr - sizeof(struct k_mem_block_id);
/* return block to the heap memory pool */
k_mem_pool_free_id(ptr);
}
return k_mem_pool_malloc(_HEAP_MEM_POOL, size);
}
void *k_calloc(size_t nmemb, size_t size)