npages_in_range(9)

💅 npages_in_range(9) — Kernel API Manual

okay bestie, so this is a page from the Kernel API Manual and honestly it's giving "small macro, big job" energy. Let's get into it ✨

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🌸 NAME 🌸

npages_in_range — literally just: calculate the number of pages in a given range. that's it. that's the whole vibe 🎀

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✨ SYNOPSIS ✨

unsigned long npages_in_range (unsigned long start , unsigned long end
);

like, you hand it two unsigned longs and it hands you back an unsigned long. no cap, that's the whole signature 🫶

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🧚 ARGUMENTS 🧚

• start — the start address of the range. where the vibe begins 💖
• end — the end address of the range. where the vibe stops 🦋

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🔥 DESCRIPTION 🔥

okay so here's the tea ☕ — this macro calculates the number of pages in a given memory range, and that range is specified by the start and end addresses.

how does it do it? it takes the difference between the end and start addresses and divides that by the page size (PAGE_SIZE) to determine the number of pages in the range. math girlie behavior, honestly 🧮💅

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👑 RETURN 👑

the number of pages in the specified range. iconic. periodt. ⭐

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🌈 SEE ALSO 🌈

no like there's a whole friend group here, iykyk 💜

• Kernel file ./drivers/gpu/drm/drm_gpusvm.c
• Overview(9)
• Locking(9)
• Partial Unmapping of Ranges(9)
• Examples(9)
• drm_gpusvm_notifier_find(9)
• drm_gpusvm_range_find(9)
• drm_gpusvm_notifier_invalidate(9)
• drm_gpusvm_init(9)
• to_drm_gpusvm_notifier(9)
• drm_gpusvm_notifier_insert(9)
• drm_gpusvm_notifier_remove(9)
• drm_gpusvm_fini(9)
• drm_gpusvm_notifier_alloc(9)
• drm_gpusvm_notifier_free(9)
• to_drm_gpusvm_range(9)
• drm_gpusvm_range_insert(9)
• __drm_gpusvm_range_remove(9)
• drm_gpusvm_range_alloc(9)
• drm_gpusvm_hmm_pfn_to_order(9)
• drm_gpusvm_check_pages(9)
• drm_gpusvm_scan_mm(9)
• drm_gpusvm_range_chunk_size(9)
• drm_gpusvm_driver_lock_held(9)
• drm_gpusvm_find_vma_start(9)
• drm_gpusvm_range_find_or_insert(9)
• __drm_gpusvm_unmap_pages(9)
• __drm_gpusvm_free_pages(9)
• drm_gpusvm_free_pages(9)
• drm_gpusvm_range_remove(9)
• drm_gpusvm_range_get(9)
• drm_gpusvm_range_destroy(9)
• drm_gpusvm_range_put(9)
• drm_gpusvm_pages_valid(9)
• drm_gpusvm_pages_valid_unlocked(9)
• drm_gpusvm_get_pages(9)
• drm_gpusvm_unmap_pages(9)
• drm_gpusvm_range_evict(9)
• drm_gpusvm_has_mapping(9)
• drm_gpusvm_range_set_unmapped(9)

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okay that's the whole page bestie, go divide something by PAGE_SIZE and slay 💅

source/version: ./drivers/gpu/drm · dated October 2026 · and yeah, it's npages_in_range(9) the whole way through 🎀✨