L4 Mapping question

[vuhlig at us.ibm.com]

Hi Robert,

there is one mapping entry per associated page per address space. that
means, if you map a page to 2 address spaces you need 2 mappings. The
current L4 version allocates the mappings statically (currently 5 entries
per frame, but this is configurable at startup time).
The idea is, that the kernel can revoke pages from sigma 0, what is not
implemented yet. I don't see the case, where you want to map a lot of pages
into all address spaces. Furthermore is your calculation not right. You can
map a page to multiple address spaces multiple times (at different virtual
addresses) - so there is no limit of needed mapping-entries per page.

Volkmar