嵌入式Linux内存管理的优化

The Optimization of Embedded Linux Memory Management

内存管理是影响嵌入式Linux实时性的一个关键因素,为了提高嵌入式Linux的实时性,对其内存管理进行了优化。首先为系统中的重要任务分配了专用的内存区域,使重要任务在内存不足时不被置换出去,以保障重要任务优先执行;然后通过利用系统空闲时间来扫描系统内存的方法,使得任务在执行时尽量减少缺页中断的发生,从而提高系统的实时性;最后通过实验对比OPT最优算法、LRU算法、优化后的LUR算法的缺页中断数和任务截止期错失率,发现优化后的LUR算法的缺页中断数和任务截止期错失率在三者中最低,说明通过以上的内存优化方法使得嵌入式Linux的实时性得到了提高。

Memory management is a key factor to impact the instantaneity of embedded Linux. In order to improve the instantaneity of embedded Linux,its memory management is optimized. At first,the important task in the system is assigned a dedicated memory area,so that important task will not be swapped out when the memory is lacking,which can protect the important task precedence; Then through the method that use the system idle time to scan the system RAM,to reduce the frequency of missing page interrupt in the task execution,thereby the system instantaneity is improved. Last,the missing page interrupts numbers and the task deadline miss ratios of OPT optimization algorithm,LRU algorithm and optimized LUR algorithm are compared through experiment,and it is found that the missing page interrupts number and the task deadline miss ratio of optimized LUR algorithm is the least among the three algorithms,which indicates that the instantaneity of embedded Linux is improved through the above described memory optimization method.