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>
diff --git a/doc/kernel/memory/pools.rst b/doc/kernel/memory/pools.rst
index 7eb85f9..cdd0ff9 100644
--- a/doc/kernel/memory/pools.rst
+++ b/doc/kernel/memory/pools.rst
@@ -151,10 +151,15 @@
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 @@
* :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()`
diff --git a/include/kernel.h b/include/kernel.h
index 2a9e779..27fa8ea 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -3653,6 +3653,17 @@
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.
*
* This routine releases a previously allocated memory block back to its
@@ -3702,7 +3713,8 @@
* @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.
*
diff --git a/kernel/mempool.c b/kernel/mempool.c
index 91b7ff7..97f7886 100644
--- a/kernel/mempool.c
+++ b/kernel/mempool.c
@@ -119,6 +119,40 @@
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 @@
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)
