RFR (M) 8146410: Interpreter functions are declared and defined in the wrong files

[Andrew Haley]

On 01/05/2016 04:33 PM, Lindenmaier, Goetz wrote:

> If you are concerned about the TLB pollution, you can 
> load thread->_stack_overflow_limit and compare against that.
> If you are past that limit, you just touch a yellow page to get the
> SIGSEGV for the stack overflow. 

Very nice!

> You touch the thread nearby anyways, so that page should be 
> in the TLB.
> 
> (There is Thread::stack_overflow_limit_offset()).

That has to be far better than what we do today.

Unfortunately, the patch we're discussing removes the locally-defined
override in which such a change could be made.

Coleen, is it actually necessary to remove a cpu-specific override
for this code?  Banging all these pages blows away 20% of the L1 TLB
entries on a Cortex-A57 and 90% (!) of them on a Cortex-A53.  (At
least, this is true for 4kbyte pages; with 64k pages it's less of an
issue.)

Andrew.