STRUCT FOLIO_BATCH(9)

💅 struct folio_batch(9) — Kernel API Manual 💅

okay bestie, welcome to section 9 of the Kernel API Manual, and no, we are not gatekeeping today 🫶 today's main character is struct folio_batch, and honestly? it's giving "glorified group chat for folios." let's get into it ✨

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🎀 NAME 🎀

struct folio_batch — literally just A collection of folios. that's the whole vibe. a lil squad of folios, hanging out together 💖

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✨ SYNOPSIS ✨

bestie look at the fit, it's iconic:

struct folio_batch {
    unsigned char nr;
    unsigned char i;
    bool percpu_pvec_drained;
    struct folio *folios[FOLIO_BATCH_SIZE];
 };

not a single extra character invented, not a single one dropped. slay 💅

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🌈 Members 🌈

okay so the Members section is lowkey just vibes — the manpage doesn't list any members one by one here. no cap, that's it, that's the section. the members are living their truth in the synopsis above 👑 (and if you need the tea on the individual sub-entries of struct folio_batch, that's a you-and-the-struct conversation, not a me-and-the-struct conversation 🙈)

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🦋 DESCRIPTION 🦋

so the whole point of the folio_batch is to amortise the cost of retrieving and operating on a set of folios. like, instead of doing the expensive lil song-and-dance once per folio, you batch it up and do it for the whole crew at once. efficiency queen 🧚✨ expense? amortised. cost? spread out. we love a financially responsible data structure 💜

the order of folios in the batch may be significant — and here's the receipt: delete_from_page_cache_batch. so do not be out here shuffling the squad like it's a playlist, because sometimes position genuinely matters 😭

also, some users of the folio_batch store "exceptional" entries in it — the problematic lil divas of the batch, if you will 💀 — and those can be removed by calling folio_batch_remove_exceptionals. so if your batch has drama, there's a whole function for kicking the drama out. periodt 🌸

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/folio_batch.h — the source of truth, the origin story, the sacred text 📖
• folio_batch_init(9)
• folio_batch_add(9)
• folio_batch_next(9)

iykyk — go read them, they're the supporting cast and they absolutely ate 🔥👑

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💀 quick reminder: nothing in this page is decorative, so don't come for me if you skipped the FOLIO_BATCH_SIZE in the synopsis — it's real, it's load-bearing, it's in the struct. respect the bracket, bestie.

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and that's the whole page! this masterpiece lives in ./include/linux, stamped October 2026, and it's filed as struct folio_batch(9) — go forth and batch responsibly, bestie 🍓💖✨