ib_umem_find_best_pgoff(9)

💅 ib_umem_find_best_pgoff (9) — Kernel API Manual 🎀

okay so bestie, welcome to the glow-up page for ib_umem_find_best_pgoff 💖 this one lives in the Kernel API Manual and it's literally about picking the best hardware page size, so let's get into it ✨

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🌸 NAME 🌸

ib_umem_find_best_pgoff — find best HW page size 🫶

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✨ SYNOPSIS ✨

unsigned long ib_umem_find_best_pgoff (struct ib_umem *umem , unsigned
long pgsz_bitmap , u64 pgoff_bitmask );

no cap, that's the whole signature 👑

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🦋 ARGUMENTS 🦋

• umem — the umem struct 💅 like, the thing you're working on
• pgsz_bitmap — bitmap of HW supported page sizes 🌈
• pgoff_bitmask — mask of bits that can be represented with an offset 🎀

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💜 DESCRIPTION 💜

so this one is very similar to ib_umem_find_best_pgsz, except — plot twist — instead of accepting an IOVA, it accepts a bitmask specifying what address bits can be represented with a page offset 😌

for instance, if the HW has multiple page sizes, requires 64 byte alignemnt, and can support aligned offsets up to 4032, then pgoff_bitmask would be "111111000000" ⭐ (yes that's the literal string in the source, don't come for me 🙈)

and here's the vibe check that matters: if the pgoff_bitmask requires either alignment in the low bit or an unavailable page size for the high bits, this function returns 0 💀 like, it's giving "no valid answer" energy.

fr fr, that 0 return is a real outcome, not a suggestion — handle it 🫶

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👑 RETURN 👑

best HW page size for the parameters, or 0 if none available for the given parameters 💖

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🔥 SEE ALSO 🔥

• Kernel file ./include/rdma/ib_umem.h 🦋

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🌈 sign-off 🌈

that's the whole page babes 💅 it came from ./include/rdma and it's dated October 2026 ⭐ go forth and pick the best page size, you absolute icon 🧚‍♀️💜