Hi, It's not clear for me how logical and virtual addresses work. I would like to know the following: 1) For a kernel that has high memory starting at 896MB, and processes having pages in high memory, when there's data exchange from those user pages to the kernel or vice versa, does the kernel have to first map those addresses (i.e. modify page tables), and then access them, even if the pages are in-memory? 2) Since a 4GB space is addressable in a 32-bit system, why would the kernel maintain a 1GB logical space only? LDD3 page 415 says "the biggest consumer of kernel address space is virtual mappings for physical memory." Does this mean the page table entries that keep this mapping consume a lot of kernel space and that's why logical space is kept low? Thanks, Bahadir -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
