node_dirtyable_memory(9)

💅 node_dirtyable_memory(9) — like, the whole vibe

okay so bestie, welcome to the Kernel API Manual, and today's main character is node_dirtyable_memory(9). she's a little function with a big job and honestly? she ate. let's get into it 🎀

✨ NAME ✨

node_dirtyable_memory — number of dirtyable pages in a node 🦋

✨ SYNOPSIS ✨

unsigned long node_dirtyable_memory (struct pglist_data *pgdat );

🌸 ARGUMENTS 🌸

• pgdat — the node. that's it. that's the whole argument. she takes one (1) thing and it's the node 💜

💖 RETURN 💖

so what does she give you back? the node's number of pages potentially available for dirty page cache. yup. and this value is literally the base value for the per-node dirty limits — like the starting point everything else builds on 👑

no cap, "potentially available" is doing a lot of work in that sentence. that's the actual wording, don't come for me 🙈

🔥 SEE ALSO 🔥

okay so this is the friend group. she's in the kernel file ./mm/page-writeback.c and these are her people, all listed here exactly as they are:

• global_dirtyable_memory(9)
• domain_dirty_limits(9)
• global_dirty_limits(9)
• node_dirty_limit(9)
• node_dirty_ok(9)
• __wb_calc_thresh(9)
• balance_dirty_pages_ratelimited_flags(9)
• balance_dirty_pages_ratelimited(9)
• wb_over_bg_thresh(9)
• tag_pages_for_writeback(9)
• writeback_iter(9)
• filemap_dirty_folio(9)
• folio_redirty_for_writepage(9)
• folio_mark_dirty(9)
• folio_wait_writeback(9)
• folio_wait_writeback_killable(9)
• folio_wait_stable(9)

like, that's the whole group chat and every single one of them is invited. iykyk 💀

and that's the page, bestie! this one came from ./mm, dated October 2026, and it's filed under Kernel API Manual. slay, go read the rest of the writeback lore, mwah 🫶💖✨