On Thu, 8 Jun 2023 14:55:01 +0200 Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > This is based on an earlier blog post at people.kernel.org, > it describes the concepts about page tables that were hardest > for me to grasp when dealing with them for the first time, > such as the prevalent three-letter acronyms pfn, pgd, p4d, > pud, pmd and pte. > > I don't know if this is what people want, but it's what I would > have wanted. > > I discussed at one point with Mike Rapoport to bring this into > the kernel documentation, so here is a small proposal. > > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > Cc: Mike Rapoport <rppt@xxxxxxxxxx> > Link: https://people.kernel.org/linusw/arm32-page-tables > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Hi Linus, Reads nicely and seems like a good introduction to me. One very trivial comment but otherwise FWIW Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > + > +Over time a deeper hierarchy has been developed in response to increasing memory > +sizes. When Linux was created, 4KB pages and a single page table called > +`swapper_pg_dir` with 1024 entries was used, covering 4MB which coincided with > +the fact that Torvald's first computer had 4MB of physical memory. Entries in > +this single table was referred to as *PTE*:s - page table entries. table were referred to as (entries is plural hence were rather than was) > + > +The hierarchy reflects the fact that page table hardware has become hierarchical
