struct MM_SESSION_SPACE_FLAGS

typedef struct _MM_SESSION_SPACE_FLAGS
{
     ULONG Initialized: 1;
     ULONG DeletePending: 1;
     ULONG PoolInitialized: 1;
     ULONG DynamicVaInitialized: 1;
     ULONG WsInitialized: 1;
     ULONG PoolDestroyed: 1;
     ULONG ObjectInitialized: 1;
     ULONG Filler: 25;
} MM_SESSION_SPACE_FLAGS, *PMM_SESSION_SPACE_FLAGS;

Windows Vista Kernel Structures