KINFO_GETVMMAP(3)

📦 version 15.1, in freebsd 14.5, freebsd 15.1

🌸 NAME 🌸

okay bestie, welcome to KINFO_GETVMMAP(3) from the Library Functions Manual — this is all about kinfo_getvmmap, the function for getting per-process memory map information. 💅✨

🫶 LIBRARY 🫶

System Utilities Library (libutil, -lutil) — that’s the vibe. 🎀

✨ SYNOPSIS ✨

#include <sys/types.h>
#include <sys/user.h>
#include <libutil.h>

struct kinfo_vmentry *
kinfo_getvmmap(pid_t pid, int *cntp);

💖 DESCRIPTION 💖

So this function is your go-to for obtaining virtual memory mapping information of a particular process. 👑

The pid field contains the process identifier. It should be a process that you have privilege to access — no sneaky peeking at stuff you’re not allowed to see, bestie. 🙈

The cntp field is how the caller gets to know how many records are returned. Very demure, very useful. 🎀

This function is a wrapper around sysctl(3) with the KERN_PROC_VMMAP mib. The kernel returns a packed structure, but this function expands the data into a fixed record format. Slay. ✨

🦋 RETURN VALUES 🦋

On success, kinfo_getvmmap() returns a pointer to an array of struct kinfo_vmentry structures as defined by <sys/user.h>. That array was obtained by an internal call to malloc(3) and must be freed by the caller with a call to free(3). Don’t leave it hanging, bestie. 😭

On failure, kinfo_getvmmap() returns NULL. 💀

🔥 SEE ALSO 🔥

🌈 HISTORY 🌈

The kinfo_getvmmap() function first appeared in FreeBSD 7.0. iconic behavior. 👑

💜 CAVEATS 💜

ngl, this one matters: kinfo_getvmmap() calls can cause significant CPU consumption because calculating the residency counts requires iterating over all memory pages of the process. 😭

Setting the sysctl variable kern.proc_vmmap_skip_resident_count to 1 prevents this calculation. Consider that your built-in low-power mode. 🔋✨

mwah 💋 — this page is from Debian, dated May 10, 2020. 🫶🎀

📦 where this page comes from