Am 08.03.2016 um 10:52 hat Stefan Hajnoczi geschrieben: > On Mon, Mar 07, 2016 at 10:22:58PM +0100, Paolo Bonzini wrote: > > On 07/03/2016 21:56, Stefan Hajnoczi wrote: > > > I think the timer concept itself is troublesome. A radical approach but > > > limited to changing QED itself is to drop the timer and instead keep a > > > timestamp for the last allocating write request. Next time a write > > > request (allocating or rewriting) is about to complete, do the flush and > > > clear the need check flag as part of the write request (if 5 seconds > > > have passed since the timestamp). > > > > bdrv_qed_drain should be easy to fix in my new drain implementation, > > which is based on draining the parent before the BdrvChild-ren. It's > > just troublesome in the current one which alternates flushing and draining. > > > > I would just revert the patch that introduced bdrv_qed_drain for now, > > and reintroduce it later (note however that something was messed up in > > commit df9a681, "qed: Implement .bdrv_drain", 2015-11-12, because it > > includes some dirty bitmap stuff). > > You're right, that might be the best solution for the time being. AFAIK > the need check write is harmless. It does not result in a guest-visible > change and is basically just a flush + header update.
I think it caused occasional assertion failures. Kevin
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