STRUCT RESCTRL_CACHE(9)

💖 struct resctrl_cache(9) — Cache allocation related data 💖

okay so bestie, welcome to the Kernel API Manual, section 9 — yes we're in the big leagues now, this is the struct resctrl_cache(9) page and it's lowkey iconic. Sit down, grab a strawberry 🍓, and let's get into it.

This struct is literally the whole vibe check for cache allocation data — it's giving "everything you need to know about how this cache wants to be sliced and diced." ✨

🎀 SYNOPSIS 🎀

struct resctrl_cache {
    unsigned int    cbm_len;
    unsigned int    min_cbm_bits;
    unsigned int    shareable_bits;
    bool arch_has_sparse_bitmasks;
    bool arch_has_per_cpu_cfg;
    bool io_alloc_capable;
};

no cap, that's the whole thing. six fields, all baddies. 🫶

🌸 Members 🌸

• cbm_len — the length of the cache bit mask. that's her. that's the size of the mask, periodt. 💅
• min_cbm_bits — the minimum number of consecutive bits that gotta be set. and listen — a value of 0 here means the architecture can support zero CBM (yes, actually zero, that's a real thing, not me being dramatic 😭).
• shareable_bits — a bitmask of shareable resource with other executing entities. i.e. what this resource is willing to share with the other kids in the group chat. 👑
• arch_has_sparse_bitmasks — True if a bitmask like f00f is valid. yeah. f00f. those gaps are allowed, she's not regular, she's sparse and she's valid 🌈
• arch_has_per_cpu_cfg — True if the QOS_CFG register for this cache level has CPU scope. iykyk.
• io_alloc_capable — True if a portion of the cache can be configured for I/O traffic. so I/O gets a lil slice too, generous queen 🎀

🦋 SEE ALSO 🦋

okay this is the part where the whole friend group gets tagged. all of these live in the kernel file ./include/linux/resctrl.h and honestly? the roster is stacked:

• enum resctrl_conf_type(9)
• struct resctrl_staged_config(9)
• struct rdt_domain_hdr(9)
• struct rdt_ctrl_domain(9)
• struct mbm_cntr_cfg(9)
• struct rdt_l3_mon_domain(9)
• enum membw_throttle_mode(9)
• struct resctrl_membw(9)
• enum resctrl_schema_fmt(9)
• struct resctrl_mon(9)
• struct rdt_resource(9)
• struct resctrl_schema(9)
• resctrl_arch_sync_cpu_closid_rmid(9)
• resctrl_get_default_ctrl(9)
• resctrl_arch_mon_event_config_write(9)
• resctrl_arch_mon_event_config_read(9)
• resctrl_arch_mbm_cntr_assign_enabled(9)
• resctrl_arch_mbm_cntr_assign_set(9)
• resctrl_arch_rmid_read(9)
• resctrl_arch_rmid_read_context_check(9)
• resctrl_find_domain(9)
• resctrl_arch_reset_rmid(9)
• resctrl_arch_reset_rmid_all(9)
• resctrl_arch_reset_all_ctrls(9)
• resctrl_arch_config_cntr(9)
• resctrl_arch_cntr_read(9)
• resctrl_arch_reset_cntr(9)
• resctrl_arch_io_alloc_enable(9)
• resctrl_arch_get_io_alloc_enabled(9)

bestie heads up 🫶 — this page lives in ./include/linux, and that's the source line, not a fun lil folder to go poking at randomly. read responsibly. 💜

and that's the page!! okay love you, bye — sourced from ./include/linux, dated October 2026, and forever signed struct resctrl_cache(9). slay, go read some kernel headers 💅✨🎀