# CPU and Kernel Page Faults

Page: https://stenobird.com/podcast/the-backend-engineering-show-with-hussein-nasser-847440/cpu-and-kernel-page-faults
Text version: https://stenobird.com/podcast/the-backend-engineering-show-with-hussein-nasser-847440/cpu-and-kernel-page-faults.md
Podcast: [The Backend Engineering Show with Hussein Nasser](https://stenobird.com/podcast/the-backend-engineering-show-with-hussein-nasser-847440)
Published: 2025-11-24T15:05:00+00:00
Episode link: https://podcasters.spotify.com/pod/show/hnasr/episodes/CPU-and-Kernel-Page-Faults-e39j93o
Audio file: https://anchor.fm/s/1eb6d14/podcast/play/109732408/https%3A%2F%2Fd3ctxlq1ktw2nl.cloudfront.net%2Fstaging%2F2025-9-15%2Ff345dc2e-5952-88d4-612f-657a31510f57.m4a
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JSON: https://stenobird.com/v1/public/podcasts/the-backend-engineering-show-with-hussein-nasser-847440/episodes/cpu-and-kernel-page-faults
Duration seconds: 2917

## Resource

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

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## Transcript

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