The program address_space

A program drives its own virtual memory (docs/ARCHITECTURE.md, "The virtual memory of a program").

At its start the program runs its cases, with their numbers:

an arena: a range of 1 GiB of addresses with no memory behind it, whose

pages are committed as the arena grows, with tables of 1, 16 and 256

ranges for each kernel entry;

a sparse table: a fixed base of 1 GiB, 1024 pages committed at random;

decommit: the frames and the pages return to the budget at once, and a

page committed again is zero;

protection: a part of a mapping becomes read only, with the time of the

shoot-down when 1, 2 or 4 processors run threads of the program;

a guard page: a child program writes down its stack into a page with no

access, and the kernel stops it there;

large pages: random reads over 64 MiB of one object, through a mapping

of large pages and through a mapping of pages of 4 KiB;

the refusals, each with its error record.

The window shows the numbers. The log has one line for each case and a line "address_space: ok, ..." when each check holds. The checks do not depend on the load of the host.

The program needs the machine with the right Inspect (its own mappings) and the boot image (its child).