typedef struct _HEAP_COUNTERS
{
     ULONG TotalMemoryReserved;
     ULONG TotalMemoryCommitted;
     ULONG TotalMemoryLargeUCR;
     ULONG TotalSizeInVirtualBlocks;
     ULONG TotalSegments;
     ULONG TotalUCRs;
     ULONG CommittOps;
     ULONG DeCommitOps;
     ULONG LockAcquires;
     ULONG LockCollisions;
     ULONG CommitRate;
     ULONG DecommittRate;
     ULONG CommitFailures;
     ULONG InBlockCommitFailures;
     ULONG CompactHeapCalls;
     ULONG CompactedUCRs;
     ULONG InBlockDeccommits;
     ULONG InBlockDeccomitSize;
} HEAP_COUNTERS, *PHEAP_COUNTERS;

Windows Vista Kernel Structures