On 09-Jul-2002 Julian Elischer wrote:
> On Wed, 10 Jul 2002, Bruce Evans wrote:
>> Can these flags be changed asynchronously?  If so, then everything needs
>> to be handled by ast() anyway.  userret() should only check for work that
>> needs doing in the usual case, and hopefully there is none (except for
>> things like ktrace).
> That's an interestign way of thinking about it..
> in that case, shouldn't ast() be called from within userret()
> instead of the other way around?
> userret() is called unconditionally from both trap() and syscall()
> (or just trap() on architectures where syscall() is called by trap())
> if teh tast thing userret() did was to check if ast() should be called
> and to call it, it might simplify things..
> also, should userret() then loop back to it's start if trap is called?
> It would need to, to simulate what it is doing now..

The test you refer to is done in MD code because ensuring atomicity involves
doing MD things like disabling interrupts.  It really works quite well the
way it is atm.


John Baldwin <[EMAIL PROTECTED]>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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