Quick questions on segments and page map buckets

[John Wilson]

Hi,

Two quick questions:


   1. The design documentation here,
   
https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Durable+Memory+-+under+the+hood,
   states that the default segment count is equal to the number of logical
   cores available in the underlying machine. However, the segments array in
   PageMemory indicates that the maximum number of segments is: 1 << SEG_BITS.
   Since SEG_BITS = 4, the max # segments is 16. Did I miss something here?
   2. Reading the code in PageMemoryNoStoreImp, it looks like pages are
   allocated segment sequentially in a bump-the-pointer strategy where the
   first 8 bytes of a segment hold a pointer to the index of the last
   allocated page. If this is true, then I don't understand the point of
   having a page map buckets. Why not use a simple arithmetic index * pageSize
   to get the offset of a page?

Thanks.
John