struct MMSUBSECTION_NODE

typedef struct _MMSUBSECTION_NODE
{
     ULONG u;
     ULONG StartingSector;
     ULONG NumberOfFullSectors;
     ULONG u1;
     PMMSUBSECTION_NODE LeftChild;
     PMMSUBSECTION_NODE RightChild;
} MMSUBSECTION_NODE, *PMMSUBSECTION_NODE;

Windows Vista Kernel Structures