STRUCT MSC_WINDOW(9)

💅 struct msc_window(9) ✨

okay so this is a page from the Kernel API Manual, and bestie, it's about struct msc_window — the multiblock mode window descriptor. yes it sounds intense. no it's not scary. let's get into it 🫶

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🌸 NAME 🌸

struct msc_window — the multiblock mode window descriptor, literally the lil' record that says "this window starts here, has this many blocks, and belongs to this MSC device" 💖

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✨ SYNOPSIS ✨

struct msc_window {
    struct list_head        entry;
    unsigned long           pgoff;
    enum lockout_state      lockout;
    spinlock_t lo_lock;
    unsigned int            nr_blocks;
    unsigned int            nr_segs;
    struct msc              *msc;
    struct sg_table         _sgt;
    struct sg_table         *sgt;
 };

look at her. nine fields. main character energy fr fr 👑

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🎀 Members 🎀

the way each one of these has a whole personality:

• entry — window list linkage, and it hooks into msc::win_list. it's giving "i know a guy who knows a guy" 🌈
• pgoff — the page offset into the buffer where this window starts. where it all begins, periodt 📍
• lockout — the lockout state. see the comment below, iykyk 🙈
• lo_lock — the spinlock that serializes the lockout state. someone's gotta keep it together 💅
• nr_blocks — how many blocks (pages) are in this window. the headcount 🔢
• nr_segs — how many segments are in this window, and yes it's <= nr_blocks. important!! don't forget that part 🫶
• msc — pointer to the MSC device. this window's home base 🏠
• _sgt — array of block descriptors 🧚
• sgt — array of block descriptors. yes, again. they're twins, it's iconic ✨

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💜 SEE ALSO 💜

so many friends, so many cross-references, we love a community 🦋

Kernel file ./drivers/hwtracing/intel_th/msu.c, plus:

• struct msc_iter(9)
• struct msc(9)
• struct msu_buffer_entry(9)
• msc_is_last_win(9)
• msc_next_window(9)
• msc_find_window(9)
• msc_oldest_window(9)
• msc_win_oldest_sg(9)
• msc_buffer_iterate(9)
• msc_buffer_clear_hw_header(9)
• msc_configure(9)
• msc_disable(9)
• msc_buffer_contig_alloc(9)
• msc_buffer_contig_free(9)
• msc_buffer_contig_get_page(9)
• msc_buffer_win_alloc(9)
• msc_buffer_win_free(9)
• msc_buffer_relink(9)
• msc_buffer_free(9)
• msc_buffer_alloc(9)
• msc_buffer_unlocked_free_unless_used(9)
• msc_buffer_free_unless_used(9)
• msc_buffer_get_page(9)
• struct msc_win_to_user_struct(9)
• msc_win_to_user(9)
• intel_th_msc_window_unlock(9)

go read them. not me being a whole study guide rn 😭

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and that's the whole page bestie, you ate that 💅✨ this came from ./drivers/hwtracing/intel_th, dated October 2026 — mwah, catch you on the next manpage 🎀💖