Memory snapshots: Checkpoint/restore for sub-second startup

This post details the implementation of memory snapshot restores for serverless container startup. It explains how memory snapshots, derived from CRIU-like technology within gVisor, capture and restore the entire state of a Linux container's process tree. The primary benefit is a significant reduction in cold start latency, particularly for Python workloads, by avoiding thousands of filesystem operations and syscalls during program initialization. The performance gains are attributed to prioritized background page loading and aggressive preloading of pages into the host page cache. The post also discusses the lifecycle management of snapshots, including compatibility considerations with CPU featuresets, NVIDIA drivers, and container runtimes, and highlights the tradeoffs of increased system complexity.