November 3, 2025
Blocked link, unlocked takes
A Friendly Tour of Process Memory on Linux
Linux memory magic, blocked links, and 6502 nostalgia collide
TLDR: The article explains how Linux fakes a neat, big memory using pages and tables, with safeguards for Meltdown and tools to peek inside. The comments veer from one reader’s blocked link frustration to another’s nostalgia for old-school chips, highlighting a split between modern complexity and simple, transparent computing.
A breezy explainer breaks down how Linux makes your app think it has one giant, tidy memory space—when it’s really juggling tiny chunks called pages, using a page list to match pretend addresses to real spots in RAM, swapping to disk when crowded, and even doing a security shimmy to avoid Meltdown. It shows how to peek at the truth with /proc and what those mysterious vdso/vvar regions are. But the comments? Pure spectacle. One reader hit a hard wall—“blocked”—and couldn’t even open the site, instantly turning the thread into a corporate‑firewall horror story. Meanwhile, another went full retro romantic, dreaming of the days of the 6502, wishing modern computing would ditch all the “pretend” and get back to chips that do exactly what they say, no smoke, no mirrors. So the vibe oscillated between “why is the link flagged?” and “bring back simple machines”, with jokes about memory maps being scarier than haunted houses and “huge pages” sounding like giant book club selections. Tech lesson: Linux uses clever tricks to make memory easy. Comment section: nostalgia vs. network nanny showdown
Key Points
- •Linux provides processes a virtual memory view mapped to physical frames via page tables and PTEs.
- •Missing mappings trigger page faults; the kernel allocates or denies access, and may swap or reload pages under memory pressure.
- •A process address space is organized into VMAs, contiguous regions with shared permissions and backing.
- •mmap, mprotect, and munmap are the primary interfaces to create, modify, and remove mappings; most work occurs lazily on first access.
- •/proc/self/maps reveals a process’s layout, including binary segments, heap, libraries, stacks, and special vDSO/vvar regions; huge pages (2 MiB, 1 GiB) exist on x86‑64, and kernels include steps related to Meltdown mitigations.