>> It actually does have some cost in that form, namely the fact that the >> kernel 1:1 mapping needs to be 4MB-aligned in order to take advantage of >> large-pte support. So we'd have to move the kernel to something like >> 0xc0400000 (and preferably higher, to make sure there is a nice hole in >> between - say 0xc1000000), which in turn has a cost of verifying that >> nothing assumes the current lay-out (we've had the 1/2/3GB TASK_SIZE >> patches floating around, but they've never had "odd sizes"). I should explicitly state that with PAE on, you need to be PMD aligned (1GB) as well, which everyone seems aware of, but nobody has explicitly mentioned as far as I can see ;-) > Don't anyone go applying these yet, though. I think there has been a > bugfix or two since Martin released 2.5.68-mjb1, where these came from. > So, consider them just an example for now. Here's the latest (fixed) sequence of patches, which seems to work pretty happily. Might need some merging to get them to go against mainline, but nothing major. M.