c82f44c4f3
There are many small memory block in NuttX system, eg: struct tcb_s, struct inode, etc, and several disadvantages about them: 1.Their frequent allocate and free cause the system memory fragmentation. 2.Since each memory block has an overhead, the utilization of small memory blocks is relatively low, which will cause memory waste. So we can use mempool to alloc smallo block, to improve alloc speed and utilization, to reduce fragmentation. Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
/****************************************************************************
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* mm/mm_heap/mm_malloc_size.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 <debug.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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* Public Functions
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****************************************************************************/
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size_t mm_malloc_size(FAR void *mem)
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{
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FAR struct mm_freenode_s *node;
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/* Protect against attempts to query a NULL reference */
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if (!mem)
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{
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return 0;
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}
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#if CONFIG_MM_HEAP_MEMPOOL_THRESHOLD != 0
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if (MM_IS_FROM_MEMPOOL(mem))
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{
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return mempool_multiple_alloc_size(mem);
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}
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#endif
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/* Map the memory chunk into a free node */
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node = (FAR struct mm_freenode_s *)((FAR char *)mem - SIZEOF_MM_ALLOCNODE);
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/* Sanity check against double-frees */
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DEBUGASSERT(node->preceding & MM_ALLOC_BIT);
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return node->size - SIZEOF_MM_ALLOCNODE;
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}
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