/**************************************************************************** * mm/mm_heap/mm_extend.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include "mm_heap/mm.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define MIN_EXTEND (2 * SIZEOF_MM_ALLOCNODE) /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: mm_extend * * Description: * Extend a heap region by add a block of (virtually) contiguous memory * to the end of the heap. * ****************************************************************************/ void mm_extend(FAR struct mm_heap_s *heap, FAR void *mem, size_t size, int region) { FAR struct mm_allocnode_s *oldnode; FAR struct mm_allocnode_s *newnode; uintptr_t blockstart; uintptr_t blockend; bool ret; /* Make sure that we were passed valid parameters */ DEBUGASSERT(heap && mem); #if CONFIG_MM_REGIONS > 1 DEBUGASSERT(size >= MIN_EXTEND && (size_t)region < (size_t)heap->mm_nregions); #else DEBUGASSERT(size >= MIN_EXTEND && region == 0); #endif /* Make sure that the memory region are properly aligned */ blockstart = (uintptr_t)mem; blockend = blockstart + size; DEBUGASSERT(MM_ALIGN_UP(blockstart) == blockstart); DEBUGASSERT(MM_ALIGN_DOWN(blockend) == blockend); /* Take the memory manager mutex */ ret = mm_lock(heap); DEBUGASSERT(ret); /* Get the terminal node in the old heap. The block to extend must * immediately follow this node. */ oldnode = heap->mm_heapend[region]; DEBUGASSERT((uintptr_t)oldnode + SIZEOF_MM_ALLOCNODE == (uintptr_t)mem); /* The size of the old node now extends to the new terminal node. * This is the old size (SIZEOF_MM_ALLOCNODE) plus the size of * the block (size) minus the size of the new terminal node * (SIZEOF_MM_ALLOCNODE) or simply: */ oldnode->size = size; /* The old node should already be marked as allocated */ DEBUGASSERT((oldnode->preceding & MM_ALLOC_BIT) != 0); /* Get and initialize the new terminal node in the heap */ newnode = (FAR struct mm_allocnode_s *) (blockend - SIZEOF_MM_ALLOCNODE); newnode->size = SIZEOF_MM_ALLOCNODE; newnode->preceding = oldnode->size | MM_ALLOC_BIT; heap->mm_heapend[region] = newnode; mm_unlock(heap); /* Finally "free" the new block of memory where the old terminal node was * located. */ mm_free(heap, (FAR void *)mem); }