sg_get_mem_stats(3)

✨ NAME ✨

sg_get_mem_stats, sg_get_mem_stats_r, sg_free_mem_stats, sg_get_swap_stats, sg_get_swap_stats_r, sg_free_swap_stats — get VM statistics. This is the manual page for sg_get_mem_stats(3), bestie, and it is literally all about VM stats 💖

🌸 SYNOPSIS 🌸

#include <statgrab.h>

sg_mem_stats *sg_get_mem_stats (size_t *entries);

sg_mem_stats *sg_get_mem_stats_r (size_t *entries);

sg_error sg_free_mem_stats (sg_mem_stats *data);

sg_swap_stats *sg_get_swap_stats (size_t *entries);

sg_swap_stats *sg_get_swap_stats_r (size_t *entries);

sg_error sg_free_swap_stats (sg_swap_stats *data);

🦋 DESCRIPTION 🦋

okay so memory stats come through sg_get_mem_stats() and sg_get_mem_stats_r(). Both of them hand you back a pointer to a sg_mem_stats buffer. Quick note bestie: this statistic doesn't need to map the entire physical memory usage — it represents the real memory usable by the operating system 🫶

Swap stats come through sg_get_swap_stats() and sg_get_swap_stats_r(). Both return a pointer to a sg_swap_stats buffer ✨

🌈 API Shortcut 🌈

• sg_get_mem_stats — returns sg_mem_stats *; data owner: libstatgrab (thread local)
• sg_get_mem_stats_r — returns sg_mem_stats *; data owner: caller
• sg_get_swap_stats — returns sg_swap_stats *; data owner: libstatgrab (thread local)
• sg_get_swap_stats_r — returns sg_swap_stats *; data owner: caller

The sg_mem_stats buffer you get from sg_get_mem_stats_r() and the sg_swap_stats buffer you get from sg_get_swap_stats_r() must be freed using sg_free_mem_stats() or sg_free_swap_stats(), respectively, when they're not needed any more. The caller is responsible for doing it — that's you, bestie 💅

🚨 FreeBSD heads-up: on the FreeBSD operating system, elevated privileges are required to access the swap statistics. Making the program setgid kmem should be sufficient. Programs running as root will not have this problem.

💖 RETURN VALUES 💖

The VM system calls can return a pointer to either a sg_mem_stats or a sg_swap_stats 👑

✨ sg_mem_stats ✨

typedef struct{
        unsigned long long total;
        unsigned long long free;
        unsigned long long used;
        unsigned long long cache;
        time_t systime;
} sg_mem_stats;

• total — the total amount of real memory, in bytes
• free — the free amount of real memory, in bytes
• used — the used amount of real memory, in bytes
• cache — the amount of real memory in bytes used for caching
• systime — the timestamp when those stats got collected, in seconds since epoch

🎀 sg_swap_stats 🎀

typedef struct {
        unsigned long long total;
        unsigned long long used;
        unsigned long long free;
        time_t systime;
} sg_swap_stats;

• total — the total swap space, in bytes
• used — the used swap, in bytes
• free — the free swap, in bytes
• systime — the timestamp when those stats got collected, in seconds since epoch

🫶 TODO 🫶

TODO time, bestie: add a function to hold open the file descriptor to the kernel memory structures. Doing this would allow the elevated privileges to be dropped early on 🔥

🔥 SEE ALSO 🔥

statgrab(3) — go check it out, iykyk 🌟

🌐 WEBSITE 🌐

⟨https://libstatgrab.org/⟩ — that's the website, no cap 🦋

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okay that's the whole vibe: this page is from libstatgrab, dated 2019-03-08, and it's literally sg_get_mem_stats(3). bye bestie 💅✨🫶