rds_page_remainder_alloc(9)

🎀 NAME 🎀

rds_page_remainder_alloc — bestie, this one's all about building up regions of a message ✨

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🌸 SYNOPSIS 🌸

int rds_page_remainder_alloc (struct scatterlist *scat , unsigned long
bytes , gfp_t gfp );

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🦋 ARGUMENTS 🦋

• scat — the scatter list for the message, okurrr 💅 that's the thing getting filled up.
• bytes — literally the number of bytes needed. that's it, that's the whole vibe.
• gfp — the waiting behaviour of the allocation. yes ma'am, this decides how patient we're being 🙈

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💖 DESCRIPTION 💖

okay so first thing, gfp is always ored with __GFP_HIGHMEM — no exceptions, no cap. so callers must be prepared to kmap the pages, etc. 👑

if bytes is at least a full page then this literally just returns a page from alloc_page. simple. iconic. done. ✨

but if bytes is a partial page then it gets interesting — this stores the unused region of the page in a per-cpu structure, and future partial-page allocations may be satisfied from that cached region 🧚‍♀️ so cute, so efficient. this lets us waste less memory on small allocations with minimal complexity, which is honestly the whole slay of it.

and the reason it works? the transmit path passes read-only page regions down to devices, and they hold a page reference until they're done with the region. periodt. 💅

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🔥 SEE ALSO 🔥

• Kernel file ./net/rds/page.c — go read it, iykyk 🫶

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and that's the whole page bestie!! brought to you by ./net/rds, dated October 2026, for rds_page_remainder_alloc(9) — mwah, go touch some pages 💜