# virtual-memory

Published articles for virtual-memory.

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## RSS vs VSZ in Virtual Memory: What the OOM Killer Actually Counts

DevFeed: [RSS vs VSZ in Virtual Memory: What the OOM Killer Actually Counts](<https://devfeed.tech/articles/rss-vs-vsz-in-virtual-memory-what-the-oom-killer-actually-counts-39569.md>)

Original publisher: [Read original article](<https://ankit-rana.com/logs/17-virtual-memory-rss-vsz-oom-killer/>)

Author: hello@ankit-rana.com

Published: 2026-03-17T00:00:00Z

Content type: tutorial

Language: en

Sources: [Ankit Rana | Mechanical Sympathy](<https://devfeed.tech/sources/ankit-rana-mechanical-sympathy.md>)

Topics: [Processes](<https://devfeed.tech/topics/processes.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Kernel](<https://devfeed.tech/topics/kernel.md>)

Tags: [cpu](<https://devfeed.tech/tags/cpu.md>), [linux](<https://devfeed.tech/tags/linux.md>), [memory](<https://devfeed.tech/tags/memory.md>), [observability](<https://devfeed.tech/tags/observability.md>), [operating-systems](<https://devfeed.tech/tags/operating-systems.md>), [pages](<https://devfeed.tech/tags/pages.md>), [performance](<https://devfeed.tech/tags/performance.md>), [process](<https://devfeed.tech/tags/process.md>), [virtual-memory](<https://devfeed.tech/tags/virtual-memory.md>)

### AI overview

This tutorial explains the difference between virtual address space (VSZ) and resident memory (RSS). Allocating memory usually reserves virtual addresses without immediately assigning physical pages; pages are committed when accessed, often through page faults. It concludes that Linux's OOM killer primarily responds to physical memory consumption, making RSS more useful than allocation counters when investigating process termination under load.

### Source excerpt

malloc() does not hand you RAM, it reserves virtual address space. VSZ is a credit limit; RSS is cash. Physical pages are committed one page fault at a time as you actually touch memory, which is why the reservation is cheap and the memset is expensive. The OOM killer selects on RSS, so virtual promises are not what gets your process killed.

## Linux Address Space

DevFeed: [Linux Address Space](<https://devfeed.tech/articles/linux-address-space-39608.md>)

Original publisher: [Read original article](<https://www.gauravsarma.com/posts/2018-03-02_Linux-Address-Space-45e1d0aa8c86>)

Published: 2018-03-02T00:00:00Z

Content type: tutorial

Language: en

Sources: [Gaurav Sarma's Blog](<https://devfeed.tech/sources/gaurav-sarma-s-blog.md>)

Topics: [Linux](<https://devfeed.tech/topics/linux.md>), [Processes](<https://devfeed.tech/topics/processes.md>), [Kernel](<https://devfeed.tech/topics/kernel.md>), [Linux Kernel](<https://devfeed.tech/topics/linux-kernel.md>)

Tags: [fork](<https://devfeed.tech/tags/fork.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [linux](<https://devfeed.tech/tags/linux.md>), [linux-kernel](<https://devfeed.tech/tags/linux-kernel.md>), [mmap](<https://devfeed.tech/tags/mmap.md>), [processes](<https://devfeed.tech/tags/processes.md>), [threads](<https://devfeed.tech/tags/threads.md>), [virtual-memory](<https://devfeed.tech/tags/virtual-memory.md>), [vm](<https://devfeed.tech/tags/vm.md>)

### AI overview

This article explains how Linux processes use virtual memory and how the kernel maps virtual addresses to physical memory. It describes memory permissions, common memory areas, the memory descriptor, and how address spaces are handled for forked processes and threads.

### Source excerpt

Linux processes interact with virtual memory and not the physical memory. Every process has a notion that it is the only process running in the system and hence, has unlimited access to the memory present in the system...