cpuidle_coup...llel_barrier(9)

📦 version 7.3.1, in nixpkgs unstable

💅 cpuidle_coupled_parallel_barrier — the kernel API manual, but make it make sense

okay so bestie, welcome to the glow-up of this page from the Kernel API Manual ✨ it's giving "niche but iconic," and honestly? we're obsessed. let's get into it 🎀

🌸 NAME

cpuidle_coupled_parallel_barrier — the way this function synchronizes all online coupled cpus. fr fr, it's a whole group-chat "wait for everyone to show up before we start" moment 💖

✨ SYNOPSIS

void cpuidle_coupled_parallel_barrier (struct cpuidle_device *dev ,
atomic_t *a );

like, that's the whole signature. short, sweet, slaying 💅

🦋 ARGUMENTS

  • dev — the cpuidle_device of the calling cpu. your cpu's little ID card, basically 🪪
  • a — an atomic variable to hold the barrier. this is the meeting spot, the group-chat pinned message, the "everyone reacts when you've seen this" 🫶

🔥 DESCRIPTION

okay so here's the vibe: no caller to this function will return from this function until all online cpus in the same coupled group have called this function. literally nobody leaves the function until the whole squad has pulled up. no cap 🚫🧢

and the second anybody does return? boom, the barrier is immediately available for reuse. recycling is iconic, mother earth is thriving 🌈♻️

bestie listen: the atomic variable must be initialized to 0 before any cpu calls this function, and it will be reset to 0 before any cpu returns from this function. no skipping this step. it's not a suggestion, it's the law 👑

also, lowkey important: this must only be called from within a coupled idle state handler (state.enter when state.flags has CPUIDLE_FLAG_COUPLED set). like, read the room. wrong context = chaos 💀

oh and it provides full smp barrier semantics before and after calling. yes ma'am, memory ordering handled, we love a thorough queen ✨🧚

👑 SEE ALSO

okay the reading list is long but every single one of these is a baddie, so let's go 💜

like, that's the whole friend group. iykyk 🫶

and that's the page, bestie! it lives under ./drivers/cpuidle, dated October 2026, and it's fr fr answering to the name cpuidle_coup...llel_barrier(9). go off, you synchronized icon 🌟💖 periodt!

📦 where this page comes from