Re: Linux-2.5.17

[David S. Miller]

   From: Linus Torvalds <[e-mail]>
   Date: Tue, 21 May 2002 19:40:08 -0700 (PDT)
   
   The early switch would at least on x86 be likely to result in the minimal
   amount of TLB flushing theoretically possible. Which I kind of like (if
   you can _prove_ that you cannot do better, you're in a good position ;).
   
Probably on sparc64 too.  The simplest way to kill off a TLB context
on sparc64 at exit_mmap() is to just mark it invalid (this means just
clearing the cpu_vm_mask of the mm_struct using that context PID).

It is even simpler than that, at exit_mmap() time we are destroying
the mm_struct anyways, nobody references it, and thus destroy_context
does all of the work.

Unfortunately, today mmdrop() (which is where destroy_context is
invoked) happens after exit_mmap().

Maybe some kind of "switch_from_dead_context()" type of thing?