Are page tables always stored in memory? Have the page tables been dumped?
I think that page tables are supported by the Linux kernel, so the memory requirement for page tables should not be replaced for the reason that there is no page fault in the kernel. But, if the pgd, pmd, pte tables are in main memory and are never swapped out, the tiered paging value cannot save memory.
So, I am confused about how the page tables themselves are managed.
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Ok, according to wikipedia, it's true that the page tables aren't swapped out - but swapping tables doesn't make them memory efficient! let's take an example: our physical memory is 4 GB in size, each page is 4 KB, so we need a 4 MB size table to map each address. the solution to this problem does not replace part of the table, but creates a hierarchy of tables, so you can select only those parts of the hierarchy that you need. explains in some detail here: Why use hierarchical page tables?
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