hmm_range_fa...cked_timeout(9)

📦 version 7.3.1, in nixpkgs unstable

💅 hmm_range_fault_unlocked_timeout — Kernel API Manual ✨

okay bestie, welcome to the hmm_range_fault_unlocked_timeout(9) page, straight out of the Kernel API Manual 🫶 this one's a function, she faults in a whole range, and she has a retry timeout, and honestly? iconic behavior. let's get into it 💖

🌸 NAME 🌸

hmm_range_fault_unlocked_timeout — fault in a range with a retry timeout ⏰

✨ SYNOPSIS ✨

int hmm_range_fault_unlocked_timeout (struct hmm_range *range , unsigned
long timeout );

so she takes a range and a timeout, returns an int, that's the whole vibe 💅

🎀 ARGUMENTS 🎀

  • range — argument structure 🦋 like, the actual range thing you're handing over
  • timeout — timeout in jiffies for internal -EBUSY retries, or 0 to retry indefinitely 🔁

💖 DESCRIPTION 💖

okay so first thing's first, and this is a big one: the caller must not hold the mmap lock 🚨 not me emphasizing this — it's literally the rule. the function takes the mmap read lock internally, all by herself, and she allows handle_mm_fault to drop it during faults. main character energy fr fr 👑

and if the mmap lock gets dropped, or the range gets invalidated? she doesn't panic, she just refreshes range->notifier_seq and restarts the walk internally. like a queen resetting her crown and going again 😌✨

now about that timeout — passing 0 for timeout retries indefinitely, periodt 🔁. a non-zero timeout is a caller policy limit for repeated mmu-notifier invalidation retries. and listen, lowkey important detail: HMM does not interrupt page fault handling when the timeout expires 😭 it just returns -EBUSY if the retry budget is exhausted before a stable range is obtained. that's the whole deal.

returns 0 on success, or one of the error codes documented for hmm_range_fault 💀 and -EINTR is returned if mmap_lock acquisition is interrupted or a fatal signal is pending during retry handling 🫶

bestie please remember: no mmap lock held by you, she handles that herself. it's giving "I got this" 💅

🦋 SEE ALSO 🦋

Kernel file ./mm/hmm.c 🌈 and her whole friend group:

and that's the page, bestie 🎀 sign-off time: this little gem lives in the source ./mm, dated October 2026, and yeah — hmm_range_fault_unlocked_timeout(9), we love her, no cap 💜⭐🍓

📦 where this page comes from