typedef struct _MMSESSION
{
     KGUARDED_MUTEX SystemSpaceViewLock;
     PKGUARDED_MUTEX SystemSpaceViewLockPointer;
     PMMVIEW SystemSpaceViewTable;
     ULONG SystemSpaceHashSize;
     ULONG SystemSpaceHashEntries;
     ULONG SystemSpaceHashKey;
     ULONG BitmapFailures;
} MMSESSION, *PMMSESSION;

Windows Vista Kernel Structures