atomic_dec_and_wake_up(9)

✨ atomic_dec_and_wake_up(9) ✨

okay so bestie, welcome to the atomic_dec_and_wake_up page from the Kernel API Manual — this one's a little kernel function that does a thing and then, like, politely tells everyone waiting that they can go now 💅

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🎀 NAME 🎀

atomic_dec_and_wake_up — decrement an atomic_t, and if it hits zero, wake up the waiters 🫶

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🌸 SYNOPSIS 🌸

bool atomic_dec_and_wake_up (atomic_t *var );

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🦋 ARGUMENTS 🦋

• var — the variable to dec and test ✨ (yes, both, it's a whole multitasking icon)

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💖 DESCRIPTION 💖

So here's the vibe: it decrements the atomic variable, and if that decrement brings it all the way down to zero, it sends a wake_up to any processes that are waiting on that variable 😭 like "bestie the count is done, you may proceed."

Highkey important: this function has the same complete ordering semantics as atomic_dec_and_test. Not "kind of similar", not "close enough" — the same complete ordering semantics. No cap. 🔥

Returns true if the variable reaches zero and the wake up was sent 👑

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👑 SEE ALSO 👑

Kernel file ./include/linux/wait_bit.h — and honestly the whole wait_bit extended universe, all of it, every single one, no skipping 🙈:

• 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)
• wake_up_var_locked(9)
• clear_and_wake_up_bit(9)
• test_and_clear_wake_up_bit(9)
• store_release_wake_up(9)

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fr fr go read the wait_bit.h crew next, they're all iconic ⭐

mwah, that's the page 💜 this lil number lives in ./include/linux and the version stamp on it is October 2026 — dated, slayed, and permanently serving 🌈💅