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

[Alex Ionescu]

Hartmut Birr wrote:

>Alex Ionescu wrote:
>
>  
>
>>hbirr at 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