Re: [Xen-devel] [Qemu-devel] [PATCH v3 6/6] qemu_calculate_timeout: increase minimum timeout to 1h

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 10 Feb 2012, Paul Brook wrote:
> > >> >  At least the floppy DMA engine is fine with it, it uses idle bottom
> > >> >  halves (which are a hack and could be replaced by timers, but that's
> > >> >  not relevant now).
> > > 
> > > I thought idle bottom halves were one of the things that made this timout
> > > necessary.  How else are they going to get run?
> > 
> > The timeout is reduced to 10 ms when an idle bottom half is scheduled.
> > See qemu_bh_update_timeout in async.c.
> 
> Ah, I see.  Idle BH are indeed a nasty hack that should be removed, but not 
> directly relevant to this 1s timeout.
> 
> I don't think this changes my overall conlusion:  Either we need this timeout 
> to poll below the user-thinks-qemu-died threshold, or we should be blocking 
> indefinitely.
 
I think you are right and the right thing to do would be blocking
indefinitely.
However if slirp doesn't support it, we could have a timeout of 1000 if
CONFIG_SLIRP, otherwise block indefinitely.

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