In summary mode, the Stack traces are not used and we can use BitMap for tracking committed/uncommitted sub-regions of a reserved memory. We take a bit. for every page in the reserved region and set it when committed or clear it when uncommitted. This makes the computation of overlapping sub-regions much simpler and faster.
To find the actual amount of committed/uncommitted memory, we can count the 1 bits before the commit/uncommit and subtract them from the requested size.