page_cache_async_readahead(9)

🌸 NAME 🌸

okay bestie, welcome to the page_cache_async_readahead(9) page in the Kernel API Manual 💖 this one is literally file readahead for marked pages. that's the whole vibe. ✨

🦋 SYNOPSIS 🦋

void page_cache_async_readahead (struct address_space *mapping , struct
file_ra_state *ra , struct file *file , struct folio *folio , unsigned
long req_count );

🎀 ARGUMENTS 🎀

• mapping — the address_space that holds the pagecache and I/O vectors 🫶
• ra — the file_ra_state that holds the readahead state ✨
• file — used by the filesystem for authentication 🔐
• folio — the folio that triggered the readahead call 👑
• req_count — total number of pages being read by the caller 💅

🔥 DESCRIPTION 🔥

okay so page_cache_async_readahead should be called when a page is used that's marked as PageReadahead — yes, that marker is the whole moment 🎀 it's literally a hint that the application has used up enough of the readahead window, so we should start pulling in more pages. no cap. 🦋

🌈 SEE ALSO 🌈

Kernel file: ./include/linux/pagemap.h — and the whole squad is right here, bestie:

• 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)
• fgf_set_order(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)
• 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)

xoxo 💅 sourced from ./include/linux, date October 2026, manual page_cache_async_readahead(9). stay iconic, bestie 💖✨