libnvme(2)

💖 libnvme(2) — API Manual 💖

okay so bestie, you're in the libnvme manual, section 2 — the API pages, the deep lore. and today's main character is a struct that's lowkey about how your drive organises its garbage collection. no cap. 🦋

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✨ NAME ✨

struct nvme_fdp_config_desc — FDP Configuration Descriptor

like, it's the descriptor that tells you how a Flexible Data Placement config is set up. it's giving "here's the map of the reclaim groups, bestie." 🗺️

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🌸 SYNOPSIS 🌸

struct nvme_fdp_config_desc {
    __le16 size;
    __u8 fdpa;
    __u8 vss;
    __le32 nrg;
    __le16 nruh;
    __le16 maxpids;
    __le32 nnss;
    __le64 runs;
    __le32 erutl;
    __u8 rsvd28[36];
    struct nvme_fdp_ruh_desc ruhs[];
};

look at her. she's structured. she's iconic. 👑

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💅 Members 💅

• size — the descriptor size. how big she is. that's it, that's the girl. 📏
• fdpa — FDP Attributes, and it's an enum nvme_fdp_config_fdpa, so you already know it's a little menu of vibes you pick from. ✨
• vss — Vendor Specific Size. the space the vendor reserved to do vendor things. mysterious. we respect it. 🙈
• nrg — Number of Reclaim Groups. that's how many reclaim groups there are, fr fr. 🎀
• nruh — Number of Reclaim Unit Handles. yes, handles. plural. we love a girl with options. 🫶
• maxpids — Max Placement Identifiers. the ceiling on placement IDs, and you should not try to exceed it. 💀
• nnss — Number of Namespaces Supported. how many namespaces this config can hold down at once. the capacity for friendship, honestly. 🌈
• runs — Reclaim Unit Nominal Size. nominal size of a reclaim unit. literal queen of measurements. ⭐
• erutl — Estimated Reclaim Unit Time Limit. estimated, bestie — estimated — so don't treat it like a promise. ⏳
• rsvd28 — Reserved. hands off. do not touch. not yours. 🚫
• ruhs — Reclaim Unit Handle descriptors, and they're struct nvme_fdp_ruh_desc. it's a flexible array member, so there are as many of these as the descriptor says there are. she goes on forever, lowkey. 🧚

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heads up bestie: this whole struct is little-endian fields (__le16, __le32, __le64) — if you're reading these raw on a big-endian box you're gonna have a bad time. byte-swap before you trust a single number. 💖

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🦋 SEE ALSO 🦋

there's genuinely no SEE ALSO section here, bestie. the original said nothing. i'm not gonna make something up. that would be lying and we don't lie in this house. 😭

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okay that's the whole page, we ate and left no crumbs. 💅

this was struct nvme_fdp_config_desc out of the libnvme API Manual, dated July 2026 — go forth and configure your FDP, bestie, and remember: reserved means reserved. 🎀✨🫶