Re: [Qemu-devel] [PATCH v2 2/2] block: bump coroutine pool size for drives

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Fri, Jul 04, 2014 at 12:03:27PM +0200, Markus Armbruster wrote:
> Stefan Hajnoczi <stefanha@redhat.com> writes:
> > @@ -2112,6 +2115,7 @@ void bdrv_detach_dev(BlockDriverState *bs, void *dev)
> >      bs->dev_ops = NULL;
> >      bs->dev_opaque = NULL;
> >      bs->guest_block_size = 512;
> > +    qemu_coroutine_adjust_pool_size(-64);
> >  }
> >  
> >  /* TODO change to return DeviceState * when all users are qdevified */
> 
> This enlarges the pool regardless of how the device model uses the block
> layer.  Isn't this a bit crude?
> 
> Have you considered adapting the number of coroutines to actual demand?
> Within reasonable limits, of course.

I picked the simplest algorithm because I couldn't think of one which is
clearly better.  We cannot predict future coroutine usage so any
algorithm will have pathological cases.

In this case we might as well stick to the simplest implementation.

Stefan

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