clear_ptes(9)

💅 clear_ptes(9) — the Kernel API Manual, bestie edition 🎀

okay so this is clear_ptes, section 9 of the Kernel API Manual, and it's lowkey one of those pages you're gonna be so glad you read instead of guessing, because guessing here is giving "undefined behaviour at 3am" 💀

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✨ NAME ✨

clear_ptes — clears present PTEs that map consecutive pages of the same folio. that's it, that's the whole job, and it eats 💅

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🌸 SYNOPSIS 🌸

void clear_ptes (struct mm_struct *mm , unsigned long addr , pte_t *ptep , unsigned int nr );

four arguments, one void, zero drama ✨

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🦋 ARGUMENTS 🦋

• mm — the address space the pages are mapped into. it's the whole vibe container 🫶
• addr — the address where the first page is mapped. like, entry zero of your little PTE party 🎀
• ptep — the page table pointer for that first entry. the main character pointer, honestly 👑
• nr — how many entries you're clearing. count them, bestie, don't vibe-guess the number 🙈

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💖 DESCRIPTION 💖

use this instead of clear_full_ptes if you know you don't need to clear the full mm — which is mostly the case, fr fr. like, most of the time you're not clearing the entire address space, you're doing a little targeted cleanup, and this is the function for that 🌈

heads up 🚨 the PTE bits in the PTE range besides the PFN can totally differ! for example, some PTEs might be write-protected. so do not come in assuming every entry looks identical — that's not the vibe check this function is passing 😭

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🔥 CONTEXT 🔥

these are the rules of the house, no cap:

• the caller holds the page table lock 🔒
• the PTEs map consecutive pages that belong to the same folio 🍓
• the PTEs are all in the same PMD ⭐

miss any of these and you're not in the club anymore, sorry, that's just how it is 🧚

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💜 SEE ALSO 💜

so much lore in this kernel file, honestly: kernel file ./include/linux/pgtable.h plus this whole friend group—

• lazy_mmu_mode_enable(9)
• lazy_mmu_mode_disable(9)
• __task_lazy_mmu_mode_pause(9)
• lazy_mmu_mode_pause(9)
• __task_lazy_mmu_mode_resume(9)
• lazy_mmu_mode_resume(9)
• pte_batch_hint(9)
• set_ptes(9)
• clear_young_dirty_ptes(9)
• get_and_clear_full_ptes(9)
• get_and_clear_ptes(9)
• clear_full_ptes(9)
• clear_nonpresent_ptes(9)
• ptep_try_set(9)
• flush_tlb_before_set(9)
• wrprotect_ptes(9)
• clear_flush_young_ptes(9)
• test_and_clear_young_ptes(9)
• modify_prot_start_ptes(9)
• modify_prot_commit_ptes(9)
• pfnmap_setup_cachemode(9)
• pfnmap_track(9)
• pfnmap_untrack(9)
• pfnmap_setup_cachemode_pfn(9)

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and that's the page, bestie!! you did it, you read the whole thing 🫶 this one lives in ./include/linux, dated October 2026, and it's clear_ptes(9) — go clear some PTEs, slay 💅✨