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Cloudflare operates one of the world's largest networks powering approximately 25 million Internet properties, serving over 46 million HTTP requests per second globally. The Performance Team owns system and application performance across Cloudflare's fleet, focusing on resource optimization, instrumentation, and visibility into hardware behavior.
This role focuses on Linux kernel memory management at scale. Memory efficiency is a high-leverage problem at Cloudflare's scale—how the kernel's memory-management subsystem behaves under pressure directly impacts both performance and infrastructure costs. Using custom low-overhead instrumentation on production servers, the team has identified several scalability bottlenecks in the kernel memory layer that appear under real workloads.
You will diagnose and fix performance and scalability bottlenecks in the Linux kernel memory-management subsystem, informed by production telemetry at a scale few environments can offer. You'll land your work upstream, contributing to mainline Linux rather than carrying private patches. You'll build and extend low-overhead kernel instrumentation (tracepoints, BPF, perf) to measure before changing and prove impact afterwards. You'll partner with kernel, networking, storage, and product engineers across the company to turn observed system behavior into concrete memory-management improvements. You'll also set technical direction for how Cloudflare uses, tunes, and evolves kernel memory management as utilization increases.
The team works upstream first—several members maintain or regularly contribute to the Linux kernel, with a default principle of fixing problems in mainline rather than carrying private patches.
REQUIREMENTS:
- Deep expertise in the Linux kernel memory-management subsystem: the page allocator, virtual memory and memory mapping, reclaim, and the locking and concurrency that hold it together
- A track record of upstream Linux contribution, ideally including maintainership or sustained work in MM (memory management) or an adjacent subsystem
- Strong systems programming in C, with the judgment to make high-risk changes to shared infrastructure safely
- Ability to dive deep into a complex codebase while keeping the fleet-wide picture in mind, and to own a problem and its outcome rather than a single patch
- Clear communication with engineers across many teams, since the symptoms of an MM problem usually show up far from the MM code
BONUSES:
- Strong understanding of Linux kernel internals pertaining to memory management
- Experience troubleshooting and resolving performance issues in large-scale distributed systems
- Experience with large-scale configuration/deployment management
