typedef struct _MMSUPPORT_FLAGS
{
     ULONG SessionSpace: 1;
     ULONG ModwriterAttached: 1;
     ULONG TrimHard: 1;
     ULONG MaximumWorkingSetHard: 1;
     ULONG ForceTrim: 1;
     ULONG MinimumWorkingSetHard: 1;
     ULONG SessionMaster: 1;
     ULONG TrimmerAttached: 1;
     ULONG TrimmerDetaching: 1;
     ULONG Reserved: 7;
     ULONG MemoryPriority: 8;
     ULONG WsleDeleted: 1;
     ULONG VmExiting: 1;
     ULONG Available: 6;
} MMSUPPORT_FLAGS, *PMMSUPPORT_FLAGS;

Windows Vista Kernel Structures