STRUCT AUXTRACE_MMAP_PARAMS(9)

💅 struct auxtrace_mmap_params(9) — Kernel API Manual, but make it make sense

okay so bestie, welcome to the <pink>struct auxtrace_mmap_params</pink> glow-up page 💖 this is from the Kernel API Manual and honestly it's giving "the setup crew for struct auxtrace_mmap" — because that's literally what it is. iykyk 🧚

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✨ NAME ✨

struct auxtrace_mmap_params — the parameters you need to set up struct auxtrace_mmap. that's it, that's the vibe 🎀

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🦋 SYNOPSIS 🦋

struct auxtrace_mmap_params {
    size_t mask;
    off_t offset;
    size_t len;
    int prot;
    int idx;
    pid_t tid;
    bool mmap_needed;
    struct perf_cpu cpu;
 };

like, look at her. main character struct energy 👑 copy it exactly, don't be weird about it.

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🌸 Members 🌸

• mask — 0 if len is not a power of two, otherwise (len - 1). that's the whole deal, no cap ✨
• offset — the file offset of the mapped area 📍
• len — size of the mapped area. she's thicc, she's measured 💅
• prot — the mmap memory protection 🛡️
• idx — the index of this mmap 🔢 (one of many, bestie)
• tid — the tid for a per-thread mmap 🧵 (it's also set if there's only 1 tid on a per-cpu mmap!) otherwise 0.
• mmap_needed — set to false for non-auxtrace events 🚫 this one's a whole thing, so listen up: it's needed because auxtrace mmapping happens in the same code path as non-auxtrace mmapping, but not every evsel that needs non-auxtrace mmapping also needs auxtrace mmapping. literally the reason this field exists, fr fr 🙈
• cpu — the cpu number for a per-cpu mmap, otherwise -1 🖥️

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🔥 SEE ALSO 🔥

Kernel file ./tools/perf/util/auxtrace.h — go read it, it's iconic:

• struct itrace_synth_opts(9)
• struct auxtrace_index_entry(9)
• struct auxtrace_index(9)
• struct auxtrace(9)
• struct auxtrace_buffer(9)
• struct auxtrace_queue(9)
• struct auxtrace_queues(9)
• struct auxtrace_heap_item(9)
• struct auxtrace_heap(9)
• struct auxtrace_mmap(9)
• struct auxtrace_record(9)
• struct addr_filter(9)
• struct addr_filters(9)

the whole friend group, slay 🌈

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ok and finally the cute little sign-off: this page lives at <purple>./tools/perf/util</purple> and it's dated <mint>October 2026</mint>, and yeah it's still struct auxtrace_mmap_params(9) — bestie we've been over this 💀🫶 periodt.