Handle SG preperation for zero transfer length
Create sop context global pool

It is done to reduce memory footprint.
It also allocates memory based on NUMA nodes.
Create a log of bio commands issued to the SOP
Add I/O counters for min and max size I/O.
Most I/O should be of size 4K from block layer.
Add counters for various types of memory allocated.
Gets to know the memory footprint.