dedicated functions.
* Introduced gMappedPagesCount variable which counts the total number of
physical pages that are mapped.
* Added vm_page_get_stats() which fills in the memory related part of
the system_info structure. Used and cached pages are computed
differently, now. The "available" (== not committed) memory is no
longer used for the computation as it doesn't say anything about the
actually used/free pages (with swap support enabled it is even
less meaningful, since we first commit swap space when possible).
We do also consider the memory used by the block cache as cached
pages, now. All in all these changes should fix the memory statistics
reported by get_system_info(), IOW bug #2574.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26837 a95241bf-73f2-0310-859d-f6bbb57e9c96