This paper proposes iSwap, a new memory page swap mechanism that reduces the ineffective I/O swap operations and improves the QoS for applications with a high priority in the cloud environments. iSwap works in the OS kernel. iSwap accurately learns the reuse patterns for memory pages and makes the swap decisions accordingly to avoid ineffective operations. In the cases where memory pressure is high, iSwap compresses pages that belong to the latency-critical (LC) applications (or high-priority applications) and keeps them in main memory, avoiding I/O operations for these LC applications to ensure QoS; and iSwap evicts low-priority applications’ pages out of main memory. iSwap has a low overhead and works well for cloud applications with large memory footprints. We evaluate iSwap on Intel x86 and ARM platforms. The experimental results show that iSwap can significantly reduce ineffective swap operations (8.0% - 19.2%) and improve the QoS for LC applications (36.8% - 91.3%) in cases where memory pressure is high, compared with the latest LRU-based approach widely used in modern OSes.

本文提出了iSwap，一种新的内存页面交换机制，可以减少无效的I/O交换操作，提高云环境中高优先级应用程序的QoS。 iSwap 在操作系统内核中工作。 iSwap 准确地学习内存页面的重用模式，并相应地做出交换决策，以避免无效操作。在内存压力较高的情况下，iSwap会压缩属于延迟关键型（LC）应用程序（或高优先级应用程序）的页面并将其保留在主内存中，避免这些LC应用程序的I/O操作以保证QoS； iSwap 将低优先级应用程序的页面从主内存中逐出。 iSwap 开销较低，非常适合内存占用较大的云应用程序。我们在 Intel x86 和 ARM 平台上评估 iSwap。实验结果表明，与最新的基于 LRU 的方法相比，在内存压力较高的情况下，iSwap 可以显着减少无效交换操作（8.0% - 19.2%）并提高 LC 应用程序的 QoS（36.8% - 91.3%）用于现代操作系统。