[Qemu-devel] Re: [PATCH 11/19] use a bottom half to run timers

[Michael S. Tsirkin]

On Mon, Jan 04, 2010 at 05:54:13PM -0600, Anthony Liguori wrote:
> On 01/04/2010 02:01 PM, Michael S. Tsirkin wrote:
>> On Mon, Jan 04, 2010 at 02:24:53PM -0600, Anthony Liguori wrote:
>>    
>>> On 12/21/2009 02:09 AM, Paolo Bonzini wrote:
>>>      
>>>> Make the timer subsystem register its own bottom half instead of
>>>> placing the bottom half code in the heart of the main loop.  To
>>>> test if an alarm timer is pending, just check if the bottom half is
>>>> scheduled.
>>>>
>>>> Signed-off-by: Paolo Bonzini<address@hidden>
>>>>        
>>> I'm not a huge fan of this for a couple reasons.  The first is that it
>>> introduces a subtle semantic change.  Previously, timers always ran
>>> before bottom halves whereas after this change, timers may run after
>>> some bottoms halves but before others.  While this should be okay in
>>> principle, in practice, I'm sure it'll introduce regressions.  I'd be
>>> very surprised if cris wasn't affected by this.
>>>
>>> But more importantly, I think timer dispatch needs to be part of the
>>> select loop.  malc has a git tree that replaces host alarm timers with
>>> select() timeouts.
>>>      
>> Where is that tree?
>>    
>
> http://repo.or.cz/w/qemu/malc.git  mtloop

Don't seem to see anything there.
malc?

>> IMO we need that, I am not sure all code is as signal-safe
>> as it should be. At least crashes that I saw with winxp install
>> seem to be related to signal handling.
>>    
>
> Regards,
>
> Anthony Liguori