int mm_mallinfo(FAR struct mm_heap_s *heap, FAR struct mallinfo *info)
{
struct mm_allocnode_s *node;
size_t mxordblk = 0;
int ordblks = 0; /* Number of non-inuse chunks */
size_t uordblks = 0; /* Total allocated space */
size_t fordblks = 0; /* Total non-inuse space */
#if CONFIG_MM_REGIONS > 1
int region;
#else
# define region 0
#endif
DEBUGASSERT(info);
/* Visit each region */
#if CONFIG_MM_REGIONS > 1
for (region = 0; region < heap->mm_nregions; region++)
#endif
{
/* Visit each node in the region
* Retake the semaphore for each region to reduce latencies
*/
mm_takesemaphore(heap);
for (node = heap->mm_heapstart[region];
node < heap->mm_heapend[region];
node = (struct mm_allocnode_s *)((char*)node + node->size))
{
mvdbg("region=%d node=%p size=%p preceding=%p (%c)\n",
region, node, node->size, (node->preceding & ~MM_ALLOC_BIT),
(node->preceding & MM_ALLOC_BIT) ? 'A' : 'F');
/* Check if the node corresponds to an allocated memory chunk */
if ((node->preceding & MM_ALLOC_BIT) != 0)
{
uordblks += node->size;
}
else
{
ordblks++;
fordblks += node->size;
if (node->size > mxordblk)
{
mxordblk = node->size;
}
}
}
mm_givesemaphore(heap);
mvdbg("region=%d node=%p heapend=%p\n", region, node, heap->mm_heapend[region]);
DEBUGASSERT(node == heap->mm_heapend[region]);
uordblks += SIZEOF_MM_ALLOCNODE; /* account for the tail node */
}
#undef region
DEBUGASSERT(uordblks + fordblks == heap->mm_heapsize);
info->arena = heap->mm_heapsize;
info->ordblks = ordblks;
info->mxordblk = mxordblk;
info->uordblks = uordblks;
info->fordblks = fordblks;
return OK;
}
void free(FAR void *mem)
{
FAR struct mm_freenode_s *node;
FAR struct mm_freenode_s *prev;
FAR struct mm_freenode_s *next;
mvdbg("Freeing %p\n", mem);
/* Protect against attempts to free a NULL reference */
if (!mem)
{
return;
}
/* We need to hold the MM semaphore while we muck with the
* nodelist.
*/
mm_takesemaphore();
/* Map the memory chunk into a free node */
node = (FAR struct mm_freenode_s *)((char*)mem - SIZEOF_MM_ALLOCNODE);
node->preceding &= ~MM_ALLOC_BIT;
/* Check if the following node is free and, if so, merge it */
next = (FAR struct mm_freenode_s *)((char*)node + node->size);
if ((next->preceding & MM_ALLOC_BIT) == 0)
{
FAR struct mm_allocnode_s *andbeyond;
/* Get the node following the next node (which will
* become the new next node). We know that we can never
* index past the tail chunk because it is always allocated.
*/
andbeyond = (FAR struct mm_allocnode_s*)((char*)next + next->size);
/* Remove the next node. There must be a predecessor,
* but there may not be a successor node.
*/
DEBUGASSERT(next->blink);
next->blink->flink = next->flink;
if (next->flink)
{
next->flink->blink = next->blink;
}
/* Then merge the two chunks */
node->size += next->size;
andbeyond->preceding = node->size | (andbeyond->preceding & MM_ALLOC_BIT);
next = (FAR struct mm_freenode_s *)andbeyond;
}
/* Check if the preceding node is also free and, if so, merge
* it with this node
*/
prev = (FAR struct mm_freenode_s *)((char*)node - node->preceding);
if ((prev->preceding & MM_ALLOC_BIT) == 0)
{
/* Remove the node. There must be a predecessor, but there may
* not be a successor node.
*/
DEBUGASSERT(prev->blink);
prev->blink->flink = prev->flink;
if (prev->flink)
{
prev->flink->blink = prev->blink;
}
/* Then merge the two chunks */
prev->size += node->size;
next->preceding = prev->size | (next->preceding & MM_ALLOC_BIT);
node = prev;
}
/* Add the merged node to the nodelist */
mm_addfreechunk(node);
mm_givesemaphore();
}
FAR void *mm_malloc(FAR struct mm_heap_s *heap, size_t size)
{
FAR struct mm_freenode_s *node;
void *ret = NULL;
int ndx;
/* Handle bad sizes */
if (size <= 0)
{
return NULL;
}
/* Adjust the size to account for (1) the size of the allocated node and
* (2) to make sure that it is an even multiple of our granule size.
*/
size = MM_ALIGN_UP(size + SIZEOF_MM_ALLOCNODE);
/* We need to hold the MM semaphore while we muck with the nodelist. */
mm_takesemaphore(heap);
/* Get the location in the node list to start the search. Special case
* really big allocations
*/
if (size >= MM_MAX_CHUNK)
{
ndx = MM_NNODES-1;
}
else
{
/* Convert the request size into a nodelist index */
ndx = mm_size2ndx(size);
}
/* Search for a large enough chunk in the list of nodes. This list is
* ordered by size, but will have occasional zero sized nodes as we visit
* other mm_nodelist[] entries.
*/
for (node = heap->mm_nodelist[ndx].flink;
node && node->size < size;
node = node->flink);
/* If we found a node with non-zero size, then this is one to use. Since
* the list is ordered, we know that is must be best fitting chunk
* available.
*/
if (node)
{
FAR struct mm_freenode_s *remainder;
FAR struct mm_freenode_s *next;
size_t remaining;
/* Remove the node. There must be a predecessor, but there may not be
* a successor node.
*/
DEBUGASSERT(node->blink);
node->blink->flink = node->flink;
if (node->flink)
{
node->flink->blink = node->blink;
}
/* Check if we have to split the free node into one of the allocated
* size and another smaller freenode. In some cases, the remaining
* bytes can be smaller (they may be SIZEOF_MM_ALLOCNODE). In that
* case, we will just carry the few wasted bytes at the end of the
* allocation.
*/
remaining = node->size - size;
if (remaining >= SIZEOF_MM_FREENODE)
{
/* Get a pointer to the next node in physical memory */
next = (FAR struct mm_freenode_s*)(((char*)node) + node->size);
/* Create the remainder node */
remainder = (FAR struct mm_freenode_s*)(((char*)node) + size);
remainder->size = remaining;
remainder->preceding = size;
/* Adjust the size of the node under consideration */
node->size = size;
/* Adjust the 'preceding' size of the (old) next node, preserving
* the allocated flag.
*/
next->preceding = remaining | (next->preceding & MM_ALLOC_BIT);
/* Add the remainder back into the nodelist */
mm_addfreechunk(heap, remainder);
}
/* Handle the case of an exact size match */
node->preceding |= MM_ALLOC_BIT;
ret = (void*)((char*)node + SIZEOF_MM_ALLOCNODE);
}
mm_givesemaphore(heap);
/* If CONFIG_DEBUG_MM is defined, then output the result of the allocation
* to the SYSLOG.
*/
#ifdef CONFIG_DEBUG_MM
if (!ret)
{
mdbg("Allocation failed, size %d\n", size);
}
else
{
mvdbg("Allocated %p, size %d\n", ret, size);
}
#endif
return ret;
}
