[Kern Meetup Blr] CFP: Enhancing Live VM Migration with Userfaultfd: Extending Support to File-Backed Pages

[Ananya Sharma]

Hello everyone,

Here's our talk proposal for the June 29th,2024 Kernel meetup. 

Topic: Enhancing Live VM Migration with Userfaultfd: Extending Support to File-Backed Pages

Abstract:

We will cover the enhancement of live Virtual Machine (VM) migration through the integration of userfaultfd with file-backed pages. Userfaultfd is limited to handling anonymous pages, which can be extended to file-backed pages and can significantly improve migration efficiency and reliability. We will discuss current methodologies like CRIU, diskless migration, and novel approaches like split migration and remote paging, emphasizing how they can benefit from an evolved userfaultfd system. 

Outline:

1.    Introduction to Userfaultfd: Overview of userfaultfd in the Linux Kernel, current functionalities and limitations, and Importance in VM migration scenarios.

2.    Traditional VM Migration Techniques: Pre-copy and post-copy migration methods, role of userfaultfd in handling page faults during migration, comparative analysis with traditional CRIU (Checkpoint/Restore in Userspace) approaches.

3.    Advanced Migration Strategies: Diskless Migration: Utilizing Image Cache and Proxies, Split Migration for large memory VMs: How to optimize for performance and downtime, Remote Paging and S-memV: Enhancing scalability through userfaultfd.

4.    Challenges with File-Backed Pages: Current state: userfaultfd support limited to anonymous pages, technical challenges, and potential solutions for extending support to File-Backed Pages.

Thanks and Regards,

Ananya Sharma (MTech IIT Delhi)

Abhisek Panda (PhD IIT Delhi)