KeAcquireSpinLockAtDpcLevel macro

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

Syntax

void KeAcquireSpinLockAtDpcLevel(
  PKSPIN_LOCK SpinLock
);

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.

Return value

None

Remarks

Drivers call KeAcquireSpinLockAtDpcLevel 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. KeAcquireSpinLockAtDpcLevel assumes the caller is already running at IRQL >= DISPATCH_LEVEL, so no raise is necessary.

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

For more information about spin locks, see Spin Locks.

Requirements

   
Minimum supported client Available starting with Windows 2000.
Target Platform Universal
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL See Remarks section.
DDI compliance rules HwStorPortProhibitedDDIs, IrqlDispatch, SpinLockSafe

See also

KeAcquireInStackQueuedSpinLockAtDpcLevel

KeAcquireSpinLock

KeInitializeSpinLock

KeReleaseSpinLock

KeReleaseSpinLockFromDpcLevel

KeTryToAcquireSpinLockAtDpcLevel