Hi Tsai, The Page Table Entries contain physical addresses. The PGD and PMD entries are always present whereas as the PTE entries can be in memory or swap. But the xxx_offset macros return the virtual address as they use __va(address) to convert these physical addresses to virtual addresses. This can be done because these are valid kernel virtual addresses. ------------- Raj. On Apr 6, 2005 6:02 PM, nitin ahuja <nitin2ahuja@xxxxxxxxxxxxx> wrote: > This is what Mel Gormen says: > > pgd_offset() takes an address and the mm_struct for the process and returns the PGD entry that covers the requested address. pmd_offset() takes a PGD entry and an address and returns the relevant PMD. pte_offset() takes a PMD and returns the relevant PTE. > > Physical address space is flat, no concept of PGDs, PMDs and PTEs. So, the address returned by pmd_offset is virtual address as one would access it inside kernel. > > Nitin > > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
