On Mon, May 11, 2009 at 06:45:50PM +0300, Avi Kivity wrote: > >Right now it's fsync. By the time I'll submit the backend change it > >will still be fsync, but at least called from the posix-aio-compat > >thread pool. > > > > I think if we have cache=writeback we should ignore this. It's only needed for cache=writeback, because without that there is no reason to flush a write cache. > For cache=none and cache=writethrough we don't really need fsync, but we > do need to flush the inflight commands. What we do need for those modes is the basic barrier support because we can currently re-order requests. The next version of my patch will implement a barriers without cache flush mode, although I don't think a fdatasync without any outstanding dirty data should cause problems. (Or maybe ext3 actually is stupid enough to flush the whole fs even for that case) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
