wake_up_var_locked(9)

💖 wake_up_var_locked(9) 💖

okay so bestie, welcome to the kernel API manual, this one's wake_up_var_locked and it is literally the "hey wake up, your variable's ready" girlie of the kernel — except she does it while holding a lock, which is the whole vibe ✨

🌸 NAME 🌸

wake_up_var_locked — wake up the waiters for a variable while you're holding a spinlock or a mutex 🎀

🦋 SYNOPSIS 🦋

wake_up_var_locked (var , lock );

🍓 ARGUMENTS 🍓

• var — the address of the variable that's being waited on. yes, the actual address, not the value, we're being specific here 💅
• lock — the spinlock or mutex what protects the variable 😌 (that's the original's grammar and I'm keeping it, it's iconic)

💜 DESCRIPTION 💜

So what she does is: send a wake up for the given variable, and that variable should be waited for with wait_var_event_spinlock or wait_var_event_mutex. match made in heaven, no cap 🫶

And here's the slay part — unlike wake_up_var, no extra barriers are needed, because the locking provides sufficient sequencing. the lock is doing the heavy lifting, she's just showing up and being gorgeous ✨

fr fr though — this only makes sense if you're actually holding that lock, which is literally the name. the lock is the whole point, bestie 🌈

👑 SEE ALSO 👑

Kernel file ./include/linux/wait_bit.h — go read her, she's the main character of this whole friend group 💖

• wait_on_bit(9)
• wait_on_bit_io(9)
• wait_on_bit_timeout(9)
• wait_on_bit_action(9)
• wait_on_bit_lock(9)
• wait_on_bit_lock_io(9)
• wait_on_bit_lock_action(9)
• wait_var_event(9)
• wait_var_event_io(9)
• wait_var_event_killable(9)
• wait_var_event_timeout(9)
• wait_var_event_interruptible(9)
• wait_var_event_any_lock(9)
• wait_var_event_spinlock(9)
• wait_var_event_mutex(9)
• wake_up_var_protected(9)
• clear_and_wake_up_bit(9)
• test_and_clear_wake_up_bit(9)
• atomic_dec_and_wake_up(9)
• store_release_wake_up(9)

and that's the whole page, bestie, you ate that 💅✨ this lil gem lives in ./include/linux, dated October 2026, and it's wake_up_var_locked(9) — mwah, go wake something up (with the lock held, obviously) 😭💖