typedef struct _MMPFNENTRY
{
     ULONG PageLocation: 3;
     ULONG WriteInProgress: 1;
     ULONG Modified: 1;
     ULONG ReadInProgress: 1;
     ULONG CacheAttribute: 2;
     ULONG Priority: 3;
     ULONG Rom: 1;
     ULONG InPageError: 1;
     ULONG KernelStack: 1;
     ULONG RemovalRequested: 1;
     ULONG ParityError: 1;
} MMPFNENTRY, *PMMPFNENTRY;

Windows Vista Kernel Structures