基于脏页率的虚拟机动态内存迁移

摘要

虚拟机动态迁移中，为保证透明性和一致性，内存迁移多采用能平衡总迁移时间和宕机时间的迭代预拷贝。为减少预拷贝过程中的数据传输量、缩短总迁移时间，这里提出了一种基于脏页率预测的预拷贝机制，该机制根据局部性原理，对虚拟机内存页的脏页率做出预测，优先传输脏页率低的内存页，避免高脏页的重传。在 Xen 中的实验结果表明，该机制可行有效，减少了数据传输量，缩短了总迁移时间。%In live virtual machine migration, the pre-copy approach is usually adopted in memory migration, and this approach could balance the contradictions of total migration time and downtime for transparency and consistency. For reducing pages transferred in pre-copy and shortening total migration time, an improved pre-copy mechanism based on dirty page probability forecasting is proposed, in this mechanism, the pages’ dirty probability is forecasted according to the principle of locality, and the pages with low dirty probability is preferentially transmitted for avoiding unnecessary transmission of high dirty pages. The experiment results in Xen indicate that the proposed mechanism is feasible and effective, and could reduce the number of transferred pages and the total migration time.