Re: [libvirt] [PATCHv4 4/4] blkiotune: add qemu support for blkiotune.device_weight

29 Nov 2011


      On 11/14/2011 09:30 PM, Eric Blake wrote:
...
From: Hu Tao <hutao@cn.fujitsu.com>
Implement setting/getting per-device blkio weights in qemu,
using the cgroups blkio.weight_device tunable.
...
+    if (vm->def->blkio.ndevices) {
+        if (qemuCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_BLKIO)) {
+            for (i = 0; i < vm->def->blkio.ndevices; i++) {
+                virBlkioDeviceWeightPtr dw = &vm->def->blkio.devices[i];
+                rc = virCgroupSetBlkioDeviceWeight(cgroup, dw->path,
+                                                   dw->weight);
+                if (rc != 0) {
+                    virReportSystemError(-rc,
+                                         _("Unable to set io device weight "
+                                           "for domain %s"),
+                                         vm->def->name);
+                    goto cleanup;
+                }
+            }
+        } else {
+            qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                            _("Block I/O tuning is not available on this host"));
+        }
Copy and paste, but this should 'goto cleanup' to ensure the error is
propagated.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org