STRUCT MON_DATA(9)

💖 struct mon_data(9) 💖

okay so bestie, welcome to the kernel API manual — this one's about struct mon_data, and it's literally the monitoring details for each event file. that's it, that's the vibe. 🎀

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✨ SYNOPSIS ✨

struct mon_data {
    struct list_head        list;
    enum resctrl_res_level  rid;
    struct mon_evt          *evt;
    int domid;
    bool sum;
 };

look at her. five fields. absolute icon behavior. 👑

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🧚 Members 🧚

• list — she's a member of the global mon_data_kn_priv_list list. yes, the global one. main character energy fr fr. 💅
• rid — the resource id that's associated with the event file. that's her whole thing.
• evt — the event structure associated with the event file. like, the event's event. iconic.
• domid — okay so this one's got ✨range✨:
  • when sum is zero, this is the domain that the event file belongs to.
  • when sum is one, this is the id of the L3 cache that all the domains to be summed share.

yes, same field, two totally different jobs. she's versatile. 🌸

• sum — set for RDT_RESOURCE_L3 when the event must be summed across multiple domains. math girlie moment. 🔥

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🌈 Description 🌈

so the kernfs kn->priv field of monitoring event files points to this struct. that's the link-up. 🦋

⚠️ lowkey important: readers and writers must hold rdtgroup_mutex. no exceptions, no shortcuts, no "it'll be fine." hold the mutex. periodt. 💀

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💜 SEE ALSO 💜

• Kernel file ./fs/resctrl/internal.h
• cpumask_any_housekeeping(9)
• struct mon_evt(9)
• struct rmid_read(9)
• enum rdtgrp_mode(9)
• struct mongroup(9)
• struct rdtgroup(9)
• struct rftype(9)
• struct mbm_state(9)

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🫶 and that's the whole page bestie! this one came from ./fs/resctrl, dated October 2026 — so yeah, note the source and the date, and go be obsessed with your event files. ngl this struct ate. 💖✨🍓