On Tue, 17 Aug 2010 18:18:22 +0100, David Laight <da...@l8s.co.uk> wrote: >> Unifying sizes of certain types up to 64-bits would be a good choice >> from engineering standpoint. Actually measuring the overhead would >> answer whether it is worth. > > Why not use a 64bit type that is the union of a 64bit number and two > 32bit numbers. > A kernel that uses 32bit paddr_t would use tha approriate (for the > endianness) 32bit value, having initialised the unused half to zero. > > That would remove almost everything except the structure size overhead
Which is precisely the "problem" here :) > while maintaining binary compatibility. I don't think so; modules that manipulates 32 bits bus_addr_t will likely fail with PAE when you cross the 4GB boundary. I don't see how the union could solve that. -- Jean-Yves Migeon jeanyves.mig...@free.fr
