2010/7/23 Sage Weil <sage@xxxxxxxxxxxx>: > On Fri, 23 Jul 2010, Kevin Wolf wrote: > >> >> Actually we shouldn't be waiting inside the aio handler. We should >> >> probably be feeding the request into some wait queue and have a >> >> separate thread that drains all those requests out. Though this >> >> wouldn't help us in throttling the client memory, it's probably a more >> >> correct way to handle the problem. >> > >> > I agree with you, however I don't think that this is worth the effort. >> > I've never seen this occur when running a virtual machine, only when >> > running qemu-io. >> > >> > @Kevin: Did you follow this thread? What is your opinion? >> >> No, I'm not subscribed to your mailing list and qemu-devel isn't CCed. >> >> I'm not entirely sure what kind of queue this is about, but are you sure >> that it can only happen with large requests as issued by qemu-io? Can >> many small requests cause the same, especially with a slow network >> connection (or it might even go down for some reason? > > In theory, small requests can, yes. We haven't seen it in practice, I > don't think. > > In any case, I think any waiting/throttling just needs to happen inside > the librados library, as that is the only place that may have any > knowledge of the cluster size, throughput, and so forth. This code should > be dropped from the qemu-kvm/rbd side. That would be the best solution. Christian -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
