STRUCT RDT_HW_RESOURCE(9)

✨ struct rdt_hw_resource(9) ✨

okay so this is a page straight out of the Kernel API Manual, and it's all about struct rdt_hw_resource — literally the arch private attributes of a resctrl resource. bestie, this is the struct that holds the stuff the architecture keeps to itself, no cap 💅

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🎀 NAME 🎀

struct rdt_hw_resource — arch private attributes of a resctrl resource 🦋

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🌸 SYNOPSIS 🌸

struct rdt_hw_resource {
    struct rdt_resource     r_resctrl;
    u32 num_closid;
    unsigned int            msr_base;
    void (*msr_update)(struct msr_param *m);
    unsigned int            mon_scale;
    unsigned int            mbm_width;
    bool cdp_enabled;
    bool mbm_cntr_assign_enabled;
    bool sdciae_enabled;
 };

periodt, that's the whole shape of it 💖

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👑 Members 👑

• r_resctrl — the attributes of the resource that resctrl uses directly. main character of the struct fr fr ✨
• num_closid — the maximum number of closid this hardware can support, regardless of CDP. it gets exposed via resctrl_arch_get_num_closid so nobody gets it twisted with struct resctrl_schema's property of the same name — that one's been corrected for features like CDP, this one hasn't. iykyk 🙈
• msr_base — the base MSR address for CBMs 🔥
• msr_update — function pointer that updates QOS MSRs 💅
• mon_scale — literally: cqm counter * mon_scale = occupancy in bytes 🍓
• mbm_width — monitor width, used to detect and correct for overflow. not me being obsessed with overflow handling 😭
• cdp_enabled — the CDP state of this resource 👑
• mbm_cntr_assign_enabled — the ABMC feature is enabled 🌈
• sdciae_enabled — the SDCIAE feature (the one backing "io_alloc") is enabled ⭐

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🧚 Description 🧚

so the way this works: the members of this structure are either private to the architecture — like mbm_width, she's not talking to anybody 💀 — or they're accessed via helpers that provide abstraction, like msr_update and msr_base. cute little layer of separation, love that for us 🫶

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🌟 SEE ALSO 🌟

• Kernel file ./arch/x86/kernel/cpu/resctrl/internal.h struct arch_mbm_state(9)
• struct rdt_hw_ctrl_domain(9)
• struct rdt_hw_l3_mon_domain(9)
• struct rdt_perf_pkg_mon_domain(9)
• struct msr_param(9)

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and that's the whole page bestie!! sign-off time: this one lives in ./arch/x86/kernel/cpu/resctrl, dated October 2026, and it's struct rdt_hw_resource(9) 💜 slay, go read the internals, mwah 🎀