fgf_set_order(9)

💅 fgf_set_order(9) — like, the kernel API manual, but make it make sense ✨

okay bestie so you're in the kernel API manual, section 9, and the page you're on is literally fgf_set_order 🎀 — and yeah, that's the same fgf_set_order(9) you saw up in the corner. come sit with me, this one's short and sweet 🫶

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✨ NAME ✨

fgf_set_order — encodes a length in the fgf_t flags. that's it. that's the whole vibe check 💅

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🌸 SYNOPSIS 🌸

fgf_t fgf_set_order (size_t size );

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🦋 ARGUMENTS 🦋

• size — the suggested size of the folio you wanna create 👑 key word: suggested. it's giving "here's my wishlist," not "here's my demand."

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💖 DESCRIPTION 💖

so if you're the caller of __filemap_get_folio, you can use this little icon to hint at a preferred size for the folio that gets created 🌈

but bestie, listen, because this is the part where the plot twists:

• if there's already a folio hanging out at that index, it gets returned to you, no matter what its size is 😭 like, whatever size it is, that's what you get. no notes, no negotiation.
• if a folio gets freshly created, it may end up a totally different size than what you asked for 💀 and that's not a bug, that's just… alignment constraints, memory pressure, or other folios chilling at nearby indices. the universe said "close enough" 🧚

so like, your suggestion is a suggestion. lowkey the kernel is the main character here fr fr 🙈

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💜 SEE ALSO 💜

your reading list, bestie — all from the Kernel file ./include/linux/pagemap.h:

• filemap_set_wb_err(9)
• filemap_check_wb_err(9)
• filemap_sample_wb_err(9)
• file_sample_sb_err(9)
• mapping_set_error(9)
• mapping_set_large_folios(9)
• mapping_align_index(9)
• mapping_pmd_folio_support(9)
• folio_flush_mapping(9)
• folio_inode(9)
• folio_attach_private(9)
• folio_change_private(9)
• folio_detach_private(9)
• fgf_t(9)
• write_begin_get_folio(9)
• filemap_get_folio(9)
• filemap_lock_folio(9)
• filemap_grab_folio(9)
• find_get_page(9)
• find_lock_page(9)
• find_or_create_page(9)
• grab_cache_page_nowait(9)
• folio_next_index(9)
• folio_next_pos(9)
• folio_file_page(9)
• folio_contains(9)
• page_pgoff(9)
• folio_pos(9)
• linear_page_delta(9)
• linear_page_index(9)
• linear_anon_page_index(9)
• folio_trylock(9)
• folio_lock(9)
• lock_page(9)
• folio_lock_killable(9)
• filemap_range_needs_writeback(9)
• struct readahead_control(9)
• page_cache_sync_readahead(9)
• page_cache_async_readahead(9)
• readahead_folio(9)
• readahead_pos(9)
• readahead_length(9)
• readahead_index(9)
• readahead_count(9)
• readahead_batch_length(9)
• folio_mkwrite_check_truncate(9)
• i_blocks_per_folio(9)

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ngl, that's a lot of cross-references for a function whose whole job is "put a number in some flags." but that's the filemap life, bestie 🍓

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and that's the page!! 💖 this lil gem lives at ./include/linux and it's dated October 2026, filed under fgf_set_order(9) — slay, go read your folios, ily, bye 🎀🔥