non_block_start(9)

💖 non_block_start(9) 💖

okay so welcome to the Kernel API Manual, bestie — this little icon is all about marking the start of a zone where sleeping is a hard no. 😴🚫

✨ NAME ✨

• non_block_start — annotate the start of section where sleeping is prohibited. 💅

🎀 SYNOPSIS 🎀

non_block_start

🦋 DESCRIPTION 🦋

This one is on behalf of the oom reaper, specifically when it is calling the mmu notifiers. 🫶

The problem is that if the notifier were to block on, for example, mutex_lock, and if the process which holds that mutex were to perform a sleeping memory allocation, the oom reaper is now blocked on completion of that memory allocation. 😭 Other blocking calls like wait_event pose similar issues. fr fr.

So yeah — this is your “heads up, no sleeping in this section” annotation, and it’s giving very much main character energy for the no-block zone. ✨

🌈 SEE ALSO 🌈

• Kernel file ./include/linux/kernel.h
• might_sleep(9)
• cant_sleep(9)
• cant_migrate(9)
• non_block_end(9)
• enum system_states(9)

sending u off with love from ./include/linux, dated October 2026 💅🫶✨ no cap, that’s the whole page. 🎀💖