clear_nonpresent_ptes(9)

💅 clear_nonpresent_ptes(9)

okay so real talk — this is a page straight out of the Kernel API Manual, section 9 (the kernel-functions girlypop section, iykyk). And the function it's hyping up? clear_nonpresent_ptes. Say it with me. It's a whole mouthful but she's worth it. 🫶

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✨ NAME ✨

clear_nonpresent_ptes — clears multiple non-present PTEs that are consecutive in the pgtable. That's it. That's the whole gig. A little cleanup crew for a lil run of PTEs that are all, collectively, not present. 💀✨

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🌸 SYNOPSIS 🌸

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

no cap, she returns void and takes four things. We'll get to those. 🎀

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🦋 ARGUMENTS 🦋

okay bestie, four args, let's meet them one by one:

• mm — the address space that these ptes represent. she's the context, the main character energy of memory management. 👑
• addr — the address of the first pte. like, where the party starts. 📍
• ptep — the page table pointer for the first entry. your lil finger pointing at the beginning of the row. 👉
• nr — the number of entries to clear. how many of them are getting the ✨treatment✨. literally just a count. 🔢

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🔥 CONTEXT 🔥

before you call her, vibe check the room:

• the caller holds the page table lock. non-negotiable. do not come in here unlocked, fr fr. 🔒
• the PTEs are all not present. all of them. every single one. that's the whole premise. 🙈
• the PTEs are all in the same PMD. same PMD, same vibe. don't try to sneak one from a different PMD in there. 🚫

honestly if any of those three things aren't true, you're not in the right context for this function, and that's on you, not her. 💅

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💖 SEE ALSO 💖

the full squad — and yes, she's friends with all of them:

• Kernel file ./include/linux/pgtable.h
• 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_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)

like, that's the group chat. read the whole thread. 🧚

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and that's the page!! source lives over in ./include/linux and this particular glow-up is dated October 2026 — mwah, iconic, no notes. 🍓💜 see you at the next man 9 bestie 🎀