ISM

ISM - Intimate Shared Memosry

Every process that attaches a particular shared memory segment to its address space creates its own page table structures to map its virtual pages to the shared physical pages. That is, it maintains its own private hme_blk and sf_hment structures even though the sf_hment structures contain the same mappings across the different processes sharing the memory segment. For very large shared memory segments being shared by a large number of processes, as is typical of many commercial database installations, the practice can waste kernel memory. To overcome this drawback, Solaris implements a form of shared memory known as Inimate Shared Memory (ISM ), whereby the page table structures are shared amoung each attaching process.

This is surely important for the large scale applications, but could be bypassed in a smaller embedded port.