Module preempt 

Preemption guard — disables preemption for the lifetime of the guard.

When to use

Use PreemptGuard to protect per-CPU data structures that are only accessed from the CPU that owns them. Because no other CPU can touch them, a spin-lock is unnecessary — disabling preemption (so the current CPU cannot switch tasks mid-operation) is sufficient.

let _guard = PreemptGuard::new();
// safe to read/write per-CPU data here
// guard is dropped at end of scope → preemption re-enabled

What it does NOT protect

PreemptGuard does not protect against concurrent access from other CPUs. For shared data, use crate::sync::SpinLock instead.

Nesting

Guards can be nested: each PreemptGuard::new() increments the per-CPU preemption depth and each drop decrements it. Preemption is re-enabled only when the depth reaches 0.

Structs

PreemptGuard

RAII guard that disables preemption on the current CPU.