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