On Sat, 19 May 2007, William Lee Irwin III wrote:
However, there are numerous optimizations and features made possible
with flag bits, which might as could be made cheap by padding struct
page up to the next highest power of 2 bytes with space for flag bits.
Well the last time I tried to get this by Andi we became a bit concerned when we realized that the memory map would grow by 14% in size. Given that 4k page size challenged platforms have a huge amount of page structs that growth is significant. I think it would be fine to do it for IA64 with 16k page size but not for x86_64.