PMAP_INIT(9)

💖 PMAP_INIT(9) 💖 — Kernel Developer's Manual, bestie edition

okay so you're in the kernel dev manual, section 9, and today's main character is PMAP_INIT — the pmap subsystem glow-up. she's giving "physical memory, but make it mapped." ✨

🌸 NAME 🌸

pmap_init, pmap_init2 — initialize the pmap subsystem 🎀

✨ SYNOPSIS ✨

bestie the includes are mandatory, do not skip them, they are the outfit and the outfit must be complete 💅

#include <sys/param.h>
#include <vm/vm.h>
#include <vm/pmap.h>

void
pmap_init(void);

void
pmap_init2(void);

🦋 DESCRIPTION 🦋

okay so listen. the pmap_init() function initializes the pmap(9) sub-system. periodt. it gets called during system initialization by vm_init(), and its whole job is to initialize any structures that the pmap_init system needs in order to map between physical and virtual memory. it's literally the matchmaker between your physical and virtual memory. no cap. 🔥

the pmap_init2() function initializes a zone for the PV entries. and what are PV entries for, you ask? they're used to implement page sharing at the physical level 🫶. and here's the important part — a high water mark is set so that the system can recover from excessive numbers of PV entries. so if the PV entries get a little too main character and start hoarding, the system can still bounce back. it's giving resilience. it's giving boundaries. 💀

🌈 SEE ALSO 🌈

• pmap(9) — the icon herself 🎀

👑 AUTHORS 👑

this manual page was written by Bruce M Simpson <bms@spc.org>. we love a credited author, we stan properly attributed work, fr fr 💜

🧚 reminder bestie: this page lives in the kernel developer's manual, so it's for the people poking at the actual guts of the system. read the includes, respect the includes.

Debian · June 10, 2005 · and that's the whole PMAP_INIT(9) page, slay, go map some memory responsibly 🌸✨💖