static LOCAL_FRAME_CACHES: [SpinLock<LocalFrameCache, PreemptDisabled>; 64]Expand description
Per-CPU frame caches protected by a PreemptDisabled guardian.
These caches are only accessed from alloc_order0_cached / free_order0_cached,
which are always called with IRQs already disabled by the caller (via
IrqDisabledToken). Using PreemptDisabled instead of the default
IrqDisabled avoids redundant RFLAGS save/restore on every lock
acquisition while still preventing preemption-driven data races.
ยงSafety invariant
If any future code path acquires a LOCAL_FRAME_CACHES lock from an
interrupt handler or without IRQs disabled, this must be reverted to
SpinLock<LocalFrameCache> (default IrqDisabled guardian).