Re: TLB tiredown by ASID bump

["Toru Nishimura" <locore64%alkyltechnology.com@localhost>]

Matt Thomas has shown long comment lines;

> > BTW, how do you approach to implement a remote TLB
> > shootdown?
>
> It depends on the reason for the shootdown.  Might as include the
> comments of pmap_tlb.c here:

It'd be better organized when parts of this entire comment are
re-ordered, analysis section first and implementation part to
address the issues.  Let's say;

/*
* ... standard single core case explaination first, and then proceed to
* ... MP case
* 
* A TLB might have multiple shootdowns active concurrently.  The ...
...
* As you can see, shootdowns are not concerned with addresses, just address
* spaces. 
*
* When a change to the local TLB may require a change in the TLB's of other
* CPUs, we try to avoid sending an IPI if at all possible.  ...
...
* Normally there is a 1:1 mapping between a TLB and a CPU.  However, some
...
* update them since multiple CPUs may be changing different sets of bits at
* same time but these sets never overlap.
* ...
*/

Thanks for your intriguing feedfeek, matt.  Do you use tlbivax insn new to
e500 for any purpose?  My impression is it might not be so useful
contradicting to the intent.

Toru Nishimura / ALKYL Technology