is_zero_page(9)

💅 is_zero_page(9) — the Kernel API Manual glow-up 🎀

okay bestie, so we're in the Kernel API Manual today and the star of the show is is_zero_page(9). yes it's a real function, yes it's exactly what it sounds like, and yes it's about to be your new fave little bool. ✨

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🌸 NAME 🌸

is_zero_page — literally just Query if a page is a zero page. that's the whole vibe check. 💖

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✨ SYNOPSIS ✨

bool is_zero_page (const struct page *page );

copy it exactly like that, no cap — bool return, one const struct page * argument, and a little space before the closing paren because the kernel has aesthetic. 🫶

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🦋 ARGUMENTS 🦋

• page — the page you're querying, bestie. the one you're side-eyeing. the main character. 👑

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💜 DESCRIPTION 💜

so here's the tea: this returns true if page is one of the permanent zero pages. periodt. 🌈

like, the zero pages are permanent — they're not going anywhere — and this function is your little oracle telling you whether the page you handed it is one of them. true = yes queen, that's a zero page. anything else = not it. 💅

no guessing, no extra lore, that's genuinely the whole deal. 🍓

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🔥 SEE ALSO 🔥

buckle up buttercup, this is the long one. all of these live in the kernel file ./include/linux/mm.h and they're all absolutely invited to the group chat: 😭

• folio_page_idx(9)
• vma_flag_t(9)
• fault_flag_allow_retry_first(9)
• vma_kernel_pagesize(9)
• folio_order(9)
• folio_reset_order(9)
• folio_mapcount(9)
• folio_mapped(9)
• thp_order(9)
• thp_size(9)
• folio_get(9)
• folio_put(9)
• folio_put_refs(9)
• folios_put(9)
• vma_flags_is_cow_mapping(9)
• vma_is_cow_mapping(9)
• vma_desc_is_cow_mapping(9)
• folio_pfn(9)
• folio_mk_pte(9)
• folio_mk_pmd(9)
• folio_mk_pud(9)
• folio_maybe_dma_pinned(9)
• is_zero_folio(9)
• folio_nr_pages(9)
• folio_next(9)
• folio_shift(9)
• folio_size(9)
• folio_maybe_mapped_shared(9)
• folio_expected_ref_count(9)
• zap_vma(9)
• ptdesc_address(9)
• ptdesc_set_kernel(9)
• ptdesc_clear_kernel(9)
• ptdesc_test_kernel(9)
• pagetable_alloc(9)
• pagetable_free(9)
• vma_lookup(9)
• vma_start_pgoff(9)
• vma_end_pgoff(9)
• vma_last_pgoff(9)
• vma_start_anon_pgoff(9)
• vma_end_anon_pgoff(9)
• vma_last_anon_pgoff(9)
• mmap_action_remap(9)
• mmap_action_remap_full(9)
• mmap_action_ioremap(9)
• mmap_action_ioremap_full(9)
• mmap_action_simple_ioremap(9)
• mmap_action_map_kernel_pages(9)
• mmap_action_map_kernel_pages_full(9)
• range_is_subset(9)
• range_in_vma(9)
• range_in_vma_desc(9)
• clear_pages(9)

yup, all 53 of them. i counted so you don't have to. iykyk. 💀

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🧚 sign-off 🧚

and that's the page, bestie!! 🎀 this little icon lives in the kernel source at ./include/linux/mm.h, and the version you're reading is dated October 2026. go forth and query your zero pages, you absolute legend. 💖✨🦋