folio_dup_file_rmap_pmd(9)

💅 folio_dup_file_rmap_pmd(9) 💅

okay so bestie, welcome to the Kernel API Manual page for folio_dup_file_rmap_pmd — yes it's a mouthful, yes it's iconic, and yes we're gonna get through it together 🫶

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✨ NAME ✨

folio_dup_file_rmap_pmd — duplicating a PMD mapping of a page range of a folio. that's the whole vibe. no cap. 🦋

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🌸 SYNOPSIS 🌸

void folio_dup_file_rmap_pmd (struct folio *folio , struct page *page ,
       struct vm_area_struct *dst_vma );

literally just copy that exactly, don't be cute with it 💀

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🎀 ARGUMENTS 🎀

• folio — the folio you're duplicating the mapping of. the main character of this whole situation 👑
• page — the first page whose mapping you're duplicating. like, the starting point, the origin story ✨
• dst_vma — the destination vm area. where the mapping is headed, iykyk 🌈

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🦋 DESCRIPTION 🦋

so the page range of the folio is defined by:

[page, page + HPAGE_PMD_NR)

that's your span, that's your window, that's the whole range bestie 🎯

⚠️ the caller needs to hold the page table lock. like, fr fr, hold it. don't skip this, this is not a drill 😭

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⭐ SEE ALSO ⭐

kernel file ./include/linux/rmap.h and honestly the whole friend group:

• folio_dup_file_rmap_ptes(9)
• folio_try_dup_anon_rmap_ptes(9)
• folio_try_dup_anon_rmap_pmd(9)
• folio_try_share_anon_rmap_pte(9)
• folio_try_share_anon_rmap_pmd(9)
• page_vma_mapped_walk_restart(9)

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and that's the page!! 💖 this one lives over in ./include/linux, dated October 2026, and it's signed folio_dup_file_rmap_pmd(9) — slay, go forth and duplicate those mappings responsibly 🧚‍♀️💜