categories of global variables in the kernel

cleanlistentries, defined in gcleanlc.c

This is internal to an informal kernel object called the clean list.
There is just such object even for a SMP configuration.
The clean list enumerates those pages that are strategic to
write  onto disk. Such state runs asynchronously with domains.

As the memory tree algorithm walks down the memory tree is undefgoes state changes that are wrappd up in a packet that may be stashed in a mapping table in order that the walk can be resumed as if it had not been interrupted. This makes it as though the walk had been perfiormed at one instant. On the 370 this packet was distributed as the value of a few global variables. memoryc.c is much about this.