基于嵌入式系统的内存管理方案

发布时间：2019-05-31 19:38

【摘要】：随着嵌入式技术的不断发展，嵌入式系统在人们的社会生活中得到了广泛的应用。针对嵌入式系统内存分配具有高效性、可靠性和实时性等要求，每种嵌入式系统结合自己的实际应用情况，，都采用自己的内存管理方案。 PTmalloc作为当前嵌入式系统的主流内存管理方案，其稳定性、全面性等特点决定了其在嵌入式系统中的地位。但PTmalloc对多线程情况下大批量的内存申请、释放的处理速度不能很好的满足路由器等设备的要求，并可能造成极大的内存空间浪费。本文从PTmalloc的基本原理出发分析了PTmalloc的优点和缺点，得出了PTmalloc对大批量内存处理速度慢的原因：arena与线程不是严格的一一对应，从而导致了频繁的加解锁操作。 Tcmalloc作为应用于服务器的内存管理方案，其对多线程情况下大批量的内存申请、释放的处理速度能很好的满足路由器等设备的要求。本文从tcmalloc的基本原理出发分析了tcmalloc的优点和缺点，得出了tcmalloc会导致嵌入式系统所不能容忍的内存浪费。本文结合PTmalloc与tcmalloc的优、缺点，提出了一种新的内存管理方案，主要体现在以下几个方面： 1）以tcmalloc的多级缓存为基本框架，引用PTmalloc的切割方式来实现内存块的切割； 2）根据实际的应用情况，细化内存块的分类； 3）引入缓存控制机制来控制缓存，降低内存浪费； 4）提供内存诊断功能来用于帮助解决非法内存操作而导致的各种bug；通过在实际设备上的测试，本内存管理方案对多线程情况下大批量内存申请、释放的处理速度要比PTmalloc好，内存缓存而导致的内存浪费情况得到了很好的解决。
[Abstract]:With the continuous development of embedded technology, embedded system has been widely used in people's social life. In order to meet the requirements of high efficiency, reliability and real-time performance of embedded system memory allocation, each embedded system adopts its own memory management scheme according to its own practical application. PTmalloc, as the mainstream memory management scheme of embedded system, its stability and comprehensiveness determine its position in embedded system. However, PTmalloc can not meet the requirements of routers and other devices for a large number of memory applications under the condition of multi-thread, and may cause a great waste of memory space. Based on the basic principle of PTmalloc, this paper analyzes the advantages and disadvantages of PTmalloc, and obtains the reason why PTmalloc is slow in processing large quantities of memory: arena and thread are not strictly one-to-one correspondence, which leads to frequent locking and unlocking operations. As a memory management scheme used in server, Tcmalloc can meet the requirements of routers and other devices for a large number of memory applications under the condition of multi-thread, and the processing speed of release can meet the requirements of routers and other devices. Based on the basic principle of tcmalloc, this paper analyzes the advantages and disadvantages of tcmalloc, and concludes that tcmalloc will lead to memory waste that embedded system can not tolerate. Based on the advantages and disadvantages of PTmalloc and tcmalloc, this paper proposes a new memory management scheme, which is mainly reflected in the following aspects: 1) taking the multi-level cache of tcmalloc as the basic framework, the cutting mode of PTmalloc is used to realize the cutting of memory blocks; 2) according to the actual application situation, the classification of memory blocks is refined, 3) the cache control mechanism is introduced to control the cache, and the memory waste is reduced. 4) provide memory diagnostics to help resolve various bug; caused by illegal memory operations Through the test on the actual device, this memory management scheme has better processing speed than PTmalloc in the case of multi-thread, and the memory waste caused by memory cache has been well solved.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP333

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