ExFreeToNPagedLookasideList

The ExFreeToNPagedLookasideList routine returns a nonpaged entry to the given lookaside list or to nonpaged pool.

VOID 
  ExFreeToNPagedLookasideList(
    IN PNPAGED_LOOKASIDE_LIST  Lookaside,
    IN PVOID  Entry
    );

Parameters

Lookaside

Pointer to the head of the lookaside list, which the caller already initialized with ExInitializeNPagedLookasideList.

Entry

Pointer to the entry to be freed. The caller obtained this pointer from a preceding call to ExAllocateFromNPagedLookasideList.

Return Value

None

Headers

Declared in wdm.h and ntddk.h. Include wdm.h or ntddk.h.

Comments

ExFreeToNPagedLookasideList is the reciprocal of ExAllocateFromNPagedLookasideList. It releases a caller-allocated entry back to the caller's lookaside list or to nonpaged pool when that entry is no longer in use.

The same entry can be reallocated or another entry allocated later with a subsequent call to ExAllocateFromNPagedLookasideList. The user of the lookaside list can allocate and free such entries dynamically on an as needed basis until it calls ExDeleteNPagedLookasideList, which releases any outstanding entries in the list before it clears the system state for the given lookaside list and returns control.

If the specified lookaside list has not yet reached the system-determined maximum number of entries, ExFreeToNPagedLookasideList inserts the given entry at the front of the list. Otherwise, the buffer at Entry is released to nonpaged pool using the caller-supplied Free routine, if any, that was set up when the lookaside list was initialized or ExFreePool.

Callers of ExFreeToNPagedLookasideList must be running at IRQL <= DISPATCH_LEVEL.

See Also

ExAllocateFromNPagedLookasideList, ExDeleteNPagedLookasideList, ExInitializeNPagedLookasideList