cpu_curr_snapshot(9)

okay bestie, welcome to cpu_curr_snapshot(9) from the Kernel API Manual 💖 this page is lowkey all about grabbing a snapshot of whatever task is running on a CPU, and yes, the details matter, so let’s go ✨

💖 NAME 💖

• cpu_curr_snapshot — Return a snapshot of the currently running task. Like, a little peek at who’s on the CPU rn 👀

✨ SYNOPSIS ✨

struct task_struct * cpu_curr_snapshot (int cpu );

🎀 ARGUMENTS 🎀

• cpu — The CPU on which to snapshot the task. That’s the CPU you’re checking, bestie 💅

🦋 DESCRIPTION 🦋

okay so this function returns the task_struct pointer of the task that’s "currently" running on the specified CPU. Slay, but read the next bit 👑

⚠️ if the specified CPU was offline, the return value is whatever it is — perhaps a pointer to the task_struct structure of that CPU’s idle task, but there is no guarantee. Not me warning you twice 😭

if you’re a caller wishing for a useful return value, you must take some action to ensure that the specified CPU remains online throughout. That’s the vibe check: keep that CPU online, or the result is giving chaos 🌀

this function executes full memory barriers before and after fetching the pointer. That permits the caller to confine this function’s fetch with respect to the caller’s accesses to other shared variables. Memory-barrier realness, no cap 🧚

🌈 SEE ALSO 🌈

Kernel file ./kernel/sched/core.c is the place to look 👑 check out:

• wake_q_add(9)
• wake_q_add_safe(9)
• task_curr(9)
• try_to_wake_up(9)
• task_call_func(9)
• wake_up_process(9)
• preempt_notifier_register(9)
• preempt_notifier_unregister(9)
• prepare_task_switch(9)
• finish_task_switch(9)
• schedule_tail(9)
• schedule_preempt_disabled(9)
• preempt_schedule_notrace(9)
• init_idle(9)
• curr_task(9)

xoxo, your kernel bestie 🫶 — source/version: ./kernel/sched; date: October 2026; page: cpu_curr_snapshot(9), periodt 💅