KefAcquireSpinLockAtDpcLevel - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
// wdm.h

VOID KefAcquireSpinLockAtDpcLevel(
  PKSPIN_LOCK SpinLock
);

View the official Windows Driver Kit DDI reference

NtDoc

No description available.

Windows Driver Kit DDI reference (nf-wdm-kefacquirespinlockatdpclevel)

Description

The KefAcquireSpinLockAtDpcLevel routine acquires a spin lock when the caller is already running at IRQL >= DISPATCH_LEVEL.

Parameters

SpinLock

Pointer to an initialized KSPIN_LOCK spin lock for which the caller must provide the storage. The spin lock must be from non-paged pool.

Remarks

Drivers call KefAcquireSpinLockAtDpcLevel instead of KeAcquireSpinLock for better driver performance if and only if they are already running at an IRQL of DISPATCH_LEVEL or above.

If a driver is running at IRQL <= APC_LEVEL, it should call KeAcquireSpinLock to have IRQL raised by that routine. KefAcquireSpinLockAtDpcLevel assumes the caller is already running at IRQL >= DISPATCH_LEVEL, so no raise is necessary.

The caller should release the spin lock with KefReleaseSpinLockFromDpcLevel as quickly as possible.

For more information about spin locks, see Spin Locks.

See also