Jeremy Fitzhardinge wrote:
The Linux kernel was never a paragon of perfection - it was never meant to be. Just because a bit of cruft went unnoticed into the kernel doesn't mean we shouldn't fix it.
I don't really see what the issue is.
Fixmaps are primarily used for things that need to be mapped early before we can allocate address space dynamically. They're predominantly used for boot-time init, and rarely on any performance-critical path. The only vaguely regular use a fixmap gets during runtime is poking at apics, and that's dominated by IO time, and kmap_atomic. Statically, there's only 100 references in the kernel. And it only affects 32-bit.
Having fixmaps at link-time fixed addresses would be nice, I suppose, but hardly worth going to vast effort over.
No, but it's hardly vast effort, either.