* Unlike common anonymous pages, anonymous hugepages have no accounting code and no lru code, because we handle hugepages differently from common pages.
* anon vma does not point to pages but pages point to anon vma.
these are all in-use pages:
rmap code extensively use address space (file/anon) to extract mapping info of pages and vmas. together, pages are mapped in vma, in page tables. primarily.
secondarily, they are mapped in file/anon address spaces too.
third, swapping uses LRU of pages.
mapping count is also extensively used here in these files.
the swapping subsystem should depend on rmaps extensively, because swapping needs to remap pages on the fly.
two types of walking involved for rmaps: file and anon. address space needs to be locked at all costs. this locking will have scalability problems as we know locking means sequential code block irrespective of the number of cores we have there.
* anon vma does not point to pages but pages point to anon vma.
these are all in-use pages:
rmap code extensively use address space (file/anon) to extract mapping info of pages and vmas. together, pages are mapped in vma, in page tables. primarily.
secondarily, they are mapped in file/anon address spaces too.
third, swapping uses LRU of pages.
mapping count is also extensively used here in these files.
the swapping subsystem should depend on rmaps extensively, because swapping needs to remap pages on the fly.
two types of walking involved for rmaps: file and anon. address space needs to be locked at all costs. this locking will have scalability problems as we know locking means sequential code block irrespective of the number of cores we have there.
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