STRUCT RESCTRL_PQR_STATE(9)

💅 struct resctrl_pqr_state(9) 💅

okay bestie, welcome to the Kernel API Manual ✨ — this one lives over in ./arch/x86/include/asm and it's literally the state cache for the PQR MSR, no cap 🎀

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🌸 NAME 🌸

struct resctrl_pqr_state — the state cache for the PQR MSR, periodt 💅

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✨ SYNOPSIS ✨

struct resctrl_pqr_state {
    u32 cur_rmid;
    u32 cur_closid;
    u32 default_rmid;
    u32 default_closid;
 };

like, that's the whole vibe. four lil u32s and she's iconic 🦋

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🫶 Members 🫶

• cur_rmid — the cached Resource Monitoring ID 👑 (this is the current one, bestie)
• cur_closid — the cached Class Of Service ID ⭐
• default_rmid — the user assigned Resource Monitoring ID 💖
• default_closid — the user assigned cached Class Of Service ID 🎀 (yes girl, "user assigned cached" — that's exactly what the original says, iykyk)

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💀 Description 💀

okay so here's the tea ☕ the upper 32 bits of MSR_IA32_PQR_ASSOC contain closid, and the lower 10 bits hold rmid. and because the update to MSR_IA32_PQR_ASSOC always contains both parts, we literally have to cache them — no way around it, fr fr 😭

this struct also stores the user configured per cpu CLOSID and RMID 🌈

and plot twist, the cache is also doing us a solid: it helps avoid pointless updates if the value does not change 💅 like, why write if nothing changed? exactly. we don't. ate and left no crumbs 🔥

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🦋 SEE ALSO 🦋

• Kernel file ./arch/x86/include/asm/resctrl.h — go read it, bestie, it's giving main character energy 👑

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kay that's the whole page!! this one's from ./arch/x86/include/asm, dated October 2026, and it's filed under struct resctrl_pqr_state(9) — mwah, go slay your kernel reading 💜✨🎀