CPU and Kernel Page Faults
From The Backend Engineering Show with Hussein Nasser by Hussein Nasser
November 24, 2025 · 49 min
About this episode
This episode dissects the need and cost of page faults in the kernel.
Page faults occurs when the process tries to access a memory that isn’t backed by a physical page kernel raises a fault which loads a page. It happens on first access, stack expansion, COW, swap and much more. However it comes with a cost. In this episode of the backend engineering show I dissect the need and the cost page faults in the kernel. 0:00 Intro 4:00 Virtual memory Abstraction of physical memory Memory sharing Allow more processes to run , unused go to disk Numa, kernel can place memory near the cpu 12:00 VMA areas Text/code Data BSS Heap Stack 19:50 Kernel mode 25:30 What is a Page fault? 30:30 First access page fault 33:00 Stack Expansion page fault 34:30 CoW page fault 38:00 Swap page fault 39:39 File backed page fault 40:29 Permission page fault 45:30 Summary
People in this episode
Host: Hussein Nasser
Topics covered
- page faults
- kernel
- virtual memory
- memory management
- process management
Keywords
- CPU
- kernel page faults
- memory access
- stack expansion
- COW
- swap
- virtual memory
- VMA areas
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