Re: [ros-dev] Re: [ros-svn] [hbirr] 14443: - Fixed ExTimerRundown.

[Alex Ionescu]

Hartmut Birr wrote:

>  Alex Ionescu wrote:
>
>   
>
> >  hbirr(a)svn.reactos.com wrote:
> >
> >     
> >
> > >  - Fixed ExTimerRundown.   
> > >
> > >       
> > >  
> > Hi,
> >
> > Can you please explain some of your changes? You have introduced
> > several changes that I don't understand, such as cancelling the
> > timer's APC without actually making sure that it has an APC
> > associated, as well as slowing down the path and forcing additionnal
> > locking of the DB lock by using KeCancelTimer (which also uselessly
> > checks if the timer is inserted -- we are sure it already is).
> >     
> >  
> Hi,
>
> the thread's active timer list can only contain timers which have an apc
> associated. It isn't necessary to check for an apc. There exist a little
> gap between deliver the apc and calling the apc routine which can
> removes the timer itself from the list. In this case the timers apc and
> dpc aren't on the apc and dpc list and some of the called functions do
> nothing (KeRemoveQueueDpc, KeRemoveQueueApc, KeCancelTimer). The goal
> for my changes was get the apc2 sample working again.
> \
>   
>  
Hi,

You are absolutely right, but I was still afraid that ApcPresent might 
be set to FALSE while the timer is still on the list,  but even then, as 
you said, the functions don't do anything.

I still think however that it would be wiser to inline the KeCancelTimer 
call and avoid the Dispatcher lock acquire/release and inserted check..

Best regards,
Alex Ionescu