[libvirt] [PATCH v2 2/2] add interface for blkio.weight_device
Hu Tao
hutao at cn.fujitsu.com
Thu Sep 8 06:59:56 UTC 2011
This patch adds a parameter --weight-device to virsh command
blkiotune for setting/getting blkio.weight_device.
---
daemon/remote.c | 5 +
include/libvirt/libvirt.h.in | 9 ++
src/conf/domain_conf.c | 142 ++++++++++++++++++++++++++++++++++-
src/conf/domain_conf.h | 15 ++++
src/libvirt_private.syms | 1 +
src/qemu/qemu_cgroup.c | 22 ++++++
src/qemu/qemu_driver.c | 170 +++++++++++++++++++++++++++++++++++++++++-
src/util/cgroup.c | 33 ++++++++
src/util/cgroup.h | 3 +
tools/virsh.c | 31 ++++++++
tools/virsh.pod | 5 +-
11 files changed, 430 insertions(+), 6 deletions(-)
diff --git a/daemon/remote.c b/daemon/remote.c
index a9d0daa..ec91526 100644
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -1503,6 +1503,7 @@ remoteDispatchDomainGetBlkioParameters(virNetServerPtr server ATTRIBUTE_UNUSED,
int nparams = args->nparams;
unsigned int flags;
int rv = -1;
+ int i;
struct daemonClientPrivate *priv =
virNetServerClientGetPrivateData(client);
@@ -1547,6 +1548,10 @@ success:
cleanup:
if (rv < 0)
virNetMessageSaveError(rerr);
+ for (i = 0; i < nparams; i++) {
+ if (params[i].type == VIR_TYPED_PARAM_STRING)
+ VIR_FREE(params[i].value.s);
+ }
VIR_FREE(params);
if (dom)
virDomainFree(dom);
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index e57241c..c65d8f7 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -1137,6 +1137,15 @@ char * virDomainGetSchedulerType(virDomainPtr domain,
#define VIR_DOMAIN_BLKIO_WEIGHT "weight"
+/**
+ * VIR_DOMAIN_BLKIO_WEIGHT_DEVICE:
+ *
+ * Macro for the blkio tunable weight_device: it represents the
+ * per device weight.
+ */
+
+#define VIR_DOMAIN_BLKIO_WEIGHT_DEVICE "weight_device"
+
/* Set Blkio tunables for the domain*/
int virDomainSetBlkioParameters(virDomainPtr domain,
virTypedParameterPtr params,
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 74f8d6a..d10e30c 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -565,6 +565,108 @@ VIR_ENUM_IMPL(virDomainNumatuneMemMode, VIR_DOMAIN_NUMATUNE_MEM_LAST,
#define VIR_DOMAIN_XML_WRITE_FLAGS VIR_DOMAIN_XML_SECURE
#define VIR_DOMAIN_XML_READ_FLAGS VIR_DOMAIN_XML_INACTIVE
+/**
+ * virBlkioWeightDeviceToStr:
+ *
+ * This function returns a string representing device weights that is
+ * suitable for writing to /cgroup/blkio/blkio.weight_device, given
+ * a list of weight devices.
+ */
+int virBlkioWeightDeviceToStr(virBlkioWeightDevicePtr weightdevices,
+ int ndevices,
+ char **result)
+{
+ int len = 0;
+ int ret = -1;
+ int i, j;
+ char **weight_devices;
+ char *str;
+
+ if (VIR_ALLOC_N(weight_devices, ndevices) < 0) {
+ goto fail_nomem1;
+ }
+ for (i = 0; i < ndevices; i++) {
+ int tmp;
+ tmp = virAsprintf(&weight_devices[i], "%d:%d %d",
+ weightdevices[i].major,
+ weightdevices[i].minor,
+ weightdevices[i].weight);
+ if (tmp < 0) {
+ goto fail_nomem2;
+ }
+ len += tmp + 1; /* 1 for '\n' and the trailing '\0' */
+ }
+
+ if (VIR_ALLOC_N(str, len) < 0) {
+ goto fail_nomem2;
+ }
+ for (i = 0; i < ndevices; i++) {
+ strcat(str, weight_devices[i]);
+ strcat(str, "\n");
+ }
+ str[len-1] = '\0';
+
+ *result = str;
+
+ ret = 0;
+
+fail_nomem2:
+ for (j = 0; j < i; j++)
+ VIR_FREE(weight_devices[i]);
+ VIR_FREE(weight_devices);
+fail_nomem1:
+ if (ret != 0)
+ virReportOOMError();
+ return ret;
+}
+
+/**
+ * virDomainBlkioWeightDeviceParseXML
+ *
+ * this function parses a XML node:
+ *
+ * <device>
+ * <major>major</major>
+ * <minor>minor</minor>
+ * <weight>weight</weight>
+ * </device>
+ *
+ * and fills a virBlkioWeightDevice struct.
+ */
+static int virDomainBlkioWeightDeviceParseXML(xmlNodePtr root,
+ virBlkioWeightDevicePtr dw)
+{
+ char *c;
+ xmlNodePtr node;
+
+ if (!dw)
+ return -1;
+
+ node = root->children;
+ while (node) {
+ if (node->type == XML_ELEMENT_NODE) {
+ if (xmlStrEqual(node->name, BAD_CAST "major")) {
+ c = (char *)xmlNodeGetContent(node);
+ dw->major = atoi(c);
+ VIR_FREE(c);
+ } else if (xmlStrEqual(node->name, BAD_CAST "minor")) {
+ c = (char *)xmlNodeGetContent(node);
+ dw->minor = atoi(c);
+ VIR_FREE(c);
+ } else if (xmlStrEqual(node->name, BAD_CAST "weight")) {
+ c = (char *)xmlNodeGetContent(node);
+ dw->weight = atoi(c);
+ VIR_FREE(c);
+ }
+ }
+ node = node->next;
+ }
+
+ return 0;
+}
+
+
+
static void
virDomainObjListDataFree(void *payload, const void *name ATTRIBUTE_UNUSED)
{
@@ -1225,6 +1327,8 @@ void virDomainDefFree(virDomainDefPtr def)
VIR_FREE(def->emulator);
VIR_FREE(def->description);
+ VIR_FREE(def->blkio.weight_devices);
+
virDomainWatchdogDefFree(def->watchdog);
virDomainMemballoonDefFree(def->memballoon);
@@ -6459,6 +6563,20 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
&def->blkio.weight) < 0)
def->blkio.weight = 0;
+ n = virXPathNodeSet("./blkiotune/device", ctxt, &nodes);
+ if (n > 0) {
+ if (VIR_ALLOC_N(def->blkio.weight_devices, n) < 0) {
+ virReportOOMError();
+ goto error;
+ }
+
+ for (i = 0; i < n; i++) {
+ virDomainBlkioWeightDeviceParseXML(nodes[i], &def->blkio.weight_devices[i]);
+ }
+ def->blkio.ndevices = n;
+ VIR_FREE(nodes);
+ }
+
/* Extract other memory tunables */
if (virXPathULong("string(./memtune/hard_limit)", ctxt,
&def->mem.hard_limit) < 0)
@@ -10474,10 +10592,28 @@ virDomainDefFormatInternal(virDomainDefPtr def,
def->mem.cur_balloon);
/* add blkiotune only if there are any */
- if (def->blkio.weight) {
+ if (def->blkio.weight || def->blkio.weight_devices) {
virBufferAsprintf(buf, " <blkiotune>\n");
- virBufferAsprintf(buf, " <weight>%u</weight>\n",
- def->blkio.weight);
+
+ if (def->blkio.weight)
+ virBufferAsprintf(buf, " <weight>%u</weight>\n",
+ def->blkio.weight);
+
+ if (def->blkio.weight_devices) {
+ int i;
+
+ for (i = 0; i < def->blkio.ndevices; i++) {
+ virBufferAsprintf(buf, " <device>\n");
+ virBufferAsprintf(buf, " <major>%d</major>\n",
+ def->blkio.weight_devices[i].major);
+ virBufferAsprintf(buf, " <minor>%d</minor>\n",
+ def->blkio.weight_devices[i].minor);
+ virBufferAsprintf(buf, " <weight>%d</weight>\n",
+ def->blkio.weight_devices[i].weight);
+ virBufferAsprintf(buf, " </device>\n");
+ }
+ }
+
virBufferAsprintf(buf, " </blkiotune>\n");
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 371f270..267eb95 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1276,6 +1276,19 @@ struct _virDomainNumatuneDef {
/* Future NUMA tuning related stuff should go here. */
};
+typedef struct _virBlkioWeightDevice virBlkioWeightDevice;
+typedef virBlkioWeightDevice *virBlkioWeightDevicePtr;
+struct _virBlkioWeightDevice {
+ int major;
+ int minor;
+ int weight;
+};
+
+int virBlkioWeightDeviceToStr(virBlkioWeightDevicePtr deviceWeights,
+ int ndevices,
+ char **result);
+
+
/*
* Guest VM main configuration
*
@@ -1293,6 +1306,8 @@ struct _virDomainDef {
struct {
unsigned int weight;
+ int ndevices;
+ virBlkioWeightDevicePtr weight_devices;
} blkio;
struct {
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 0780f2d..597cd97 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -227,6 +227,7 @@ virDomainAuditVcpu;
# domain_conf.h
+virBlkioWeightDeviceToStr;
virDiskNameToBusDeviceIndex;
virDiskNameToIndex;
virDomainActualNetDefFree;
diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 2a10bd2..eb06871 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -312,6 +312,28 @@ int qemuSetupCgroup(struct qemud_driver *driver,
}
}
+ if (qemuCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_BLKIO)) {
+ for (i = 0; i < vm->def->blkio.ndevices; i++) {
+ char *tmp = NULL;
+
+ virAsprintf(&tmp, "%d:%d %d",
+ vm->def->blkio.weight_devices[i].major,
+ vm->def->blkio.weight_devices[i].minor,
+ vm->def->blkio.weight_devices[i].weight);
+ if (tmp) {
+ rc = virCgroupSetBlkioWeightDevice(cgroup, tmp);
+ VIR_FREE(tmp);
+ tmp = NULL;
+ if (rc != 0) {
+ virReportSystemError(-rc,
+ _("Unable to set io device weight for domain %s"),
+ vm->def->name);
+ goto cleanup;
+ }
+ }
+ }
+ }
+
if (vm->def->mem.hard_limit != 0 ||
vm->def->mem.soft_limit != 0 ||
vm->def->mem.swap_hard_limit != 0) {
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 1925ba5..a9e9ad5 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -44,6 +44,7 @@
#include <sys/ioctl.h>
#include <sys/un.h>
#include <byteswap.h>
+#include <ctype.h>
#include "qemu_driver.h"
@@ -112,7 +113,7 @@
# define KVM_CAP_NR_VCPUS 9 /* returns max vcpus per vm */
#endif
-#define QEMU_NB_BLKIO_PARAM 1
+#define QEMU_NB_BLKIO_PARAM 2
static void processWatchdogEvent(void *data, void *opaque);
@@ -6044,6 +6045,86 @@ cleanup:
return ret;
}
+/* weightDeviceStr in the form of major:minor,weight;nmajor:minor,weight
+ * for example, 8:0,300;8:16,800;8:32,1000
+ */
+static int parseBlkioWeightDeviceStr(const char *weightDeviceStr, virBlkioWeightDevicePtr *dw, int *size)
+{
+ const char *temp;
+ int nDevice = 0;
+ int i;
+ virBlkioWeightDevicePtr result = NULL;
+
+ if (!dw)
+ return -1;
+ if (*dw)
+ return -1;
+
+ temp = weightDeviceStr;
+ while (temp) {
+ temp = strchr(temp, ';');
+ if (temp) {
+ temp++;
+ if (*temp == '\0')
+ break;
+ nDevice++;
+ }
+ }
+ nDevice++;
+
+ if (VIR_ALLOC_N(result, nDevice) < 0) {
+ virReportOOMError();
+ return -1;
+ }
+
+ i = 0;
+ temp = weightDeviceStr;
+ while (temp && i < nDevice) {
+ const char *p = temp;
+ while (isdigit(*p) && ++p);
+ if (!p || *p != ':')
+ goto fail;
+
+ result[i].major = atoi(temp);
+
+ temp = p + 1;
+ if (!temp)
+ goto fail;
+
+ p = temp;
+ while (isdigit(*p) && ++p);
+ if (!p || *p != ',')
+ goto fail;
+
+ result[i].minor = atoi(temp);
+
+ temp = p + 1;
+ if (!temp)
+ goto fail;
+
+ p = temp;
+ while (isdigit(*p) && ++p);
+ if (!p || (*p != ';' && *p != '\0'))
+ goto fail;
+
+ result[i].weight = atoi(temp);
+
+ i++;
+ if (*p == '\0')
+ break;
+ temp = p + 1;
+ }
+
+ *dw = result;
+ *size = i;
+
+ return 0;
+
+fail:
+ VIR_FREE(result);
+ return -1;
+}
+
static int qemuDomainSetBlkioParameters(virDomainPtr dom,
virTypedParameterPtr params,
int nparams,
@@ -6110,10 +6191,10 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
ret = 0;
if (flags & VIR_DOMAIN_AFFECT_LIVE) {
for (i = 0; i < nparams; i++) {
+ int rc;
virTypedParameterPtr param = ¶ms[i];
if (STREQ(param->field, VIR_DOMAIN_BLKIO_WEIGHT)) {
- int rc;
if (param->type != VIR_TYPED_PARAM_UINT) {
qemuReportError(VIR_ERR_INVALID_ARG, "%s",
_("invalid type for blkio weight tunable, expected a 'unsigned int'"));
@@ -6134,6 +6215,44 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
_("unable to set blkio weight tunable"));
ret = -1;
}
+ } else if(STREQ(param->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE)) {
+ int ndevices;
+ virBlkioWeightDevicePtr tmp = NULL;
+ if (param->type != VIR_TYPED_PARAM_STRING) {
+ qemuReportError(VIR_ERR_INVALID_ARG, "%s",
+ _("invalid type for blkio weight_device tunable, expected a 'char *'"));
+ ret = -1;
+ continue;
+ }
+
+ if (parseBlkioWeightDeviceStr(params[i].value.s,
+ &tmp,
+ &ndevices) < 0) {
+ qemuReportError(VIR_ERR_INVALID_ARG, "%s",
+ _("invalid format for blkio weight_device"));
+ ret = -1;
+ continue;
+ }
+ for (i = 0; i < ndevices; i++) {
+ char *weight_device = NULL;
+
+ virAsprintf(&weight_device, "%d:%d %d",
+ tmp[i].major,
+ tmp[i].minor,
+ tmp[i].weight);
+ if (weight_device) {
+ rc = virCgroupSetBlkioWeightDevice(group, weight_device);
+ VIR_FREE(weight_device);
+ weight_device = NULL;
+ if (rc != 0) {
+ virReportSystemError(-rc, "%s",
+ _("unable to set blkio weight_device tunable"));
+ ret = -1;
+ break;
+ }
+ }
+ }
+ VIR_FREE(tmp);
} else {
qemuReportError(VIR_ERR_INVALID_ARG,
_("Parameter `%s' not supported"), param->field);
@@ -6163,6 +6282,21 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
}
persistentDef->blkio.weight = params[i].value.ui;
+ } else if (STREQ(param->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE)) {
+ virBlkioWeightDevicePtr tmp = NULL;
+ int ndevices;
+ if (parseBlkioWeightDeviceStr(params[i].value.s,
+ &tmp,
+ &ndevices) < 0) {
+ qemuReportError(VIR_ERR_INVALID_ARG,
+ _("invalid device weight format: %s"),
+ params[i].value.s);
+ ret = -1;
+ continue;
+ }
+ VIR_FREE(persistentDef->blkio.weight_devices);
+ persistentDef->blkio.weight_devices = tmp;
+ persistentDef->blkio.ndevices = ndevices;
} else {
qemuReportError(VIR_ERR_INVALID_ARG,
_("Parameter `%s' not supported"), param->field);
@@ -6262,6 +6396,7 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom,
if (flags & VIR_DOMAIN_AFFECT_LIVE) {
for (i = 0; i < *nparams; i++) {
+ char *weight_device;
virTypedParameterPtr param = ¶ms[i];
val = 0;
param->value.ui = 0;
@@ -6282,6 +6417,21 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom,
}
param->value.ui = val;
break;
+ case 1: /* blkio.weight_device */
+ param->type = VIR_TYPED_PARAM_STRING;
+ rc = virCgroupGetBlkioWeightDevice(group, &weight_device);
+ if (rc != 0) {
+ virReportSystemError(-rc, "%s",
+ _("unable to get blkio weight_device"));
+ goto cleanup;
+ }
+ if (virStrcpyStatic(param->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE) == NULL) {
+ qemuReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("Field blkio weight_device too long for destination"));
+ goto cleanup;
+ }
+ param->value.s = weight_device;
+ break;
default:
break;
@@ -6305,6 +6455,22 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom,
param->value.ui = persistentDef->blkio.weight;
break;
+ case 1: /* blkio.weight_device */
+ {
+ if (virBlkioWeightDeviceToStr(persistentDef->blkio.weight_devices,
+ persistentDef->blkio.ndevices,
+ ¶m->value.s) < 0)
+ goto cleanup;
+ param->type = VIR_TYPED_PARAM_STRING;
+ if (virStrcpyStatic(param->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE) == NULL) {
+ qemuReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("Field blkio weight_device too long for destination"));
+ goto cleanup;
+ }
+
+ break;
+ }
+
default:
break;
/* should not hit here */
diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index c8d1f33..f6e5a08 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -982,6 +982,39 @@ int virCgroupGetBlkioWeight(virCgroupPtr group, unsigned int *weight)
}
/**
+ * virCgroupSetBlkioWeightDevice:
+ *
+ * @group: The cgroup to change io weight device for
+ * @weight_device: The Weight device for this cgroup
+ *
+ * Returns: 0 on success
+ */
+int virCgroupSetBlkioWeightDevice(virCgroupPtr group,
+ const char *weight_device)
+{
+ return virCgroupSetValueStr(group,
+ VIR_CGROUP_CONTROLLER_BLKIO,
+ "blkio.weight_device",
+ weight_device);
+}
+
+/**
+ * virCgroupGetBlkioWeightDevice:
+ *
+ * @group: The cgroup to get weight_device for
+ * @weight_device: returned weight_device string
+ *
+ * Returns: 0 on success
+ */
+int virCgroupGetBlkioWeightDevice(virCgroupPtr group,
+ char **weight_device)
+{
+ return virCgroupGetValueStr(group,
+ VIR_CGROUP_CONTROLLER_BLKIO,
+ "blkio.weight_device", weight_device);
+}
+
+/**
* virCgroupSetMemory:
*
* @group: The cgroup to change memory for
diff --git a/src/util/cgroup.h b/src/util/cgroup.h
index d190bb3..87e196b 100644
--- a/src/util/cgroup.h
+++ b/src/util/cgroup.h
@@ -55,6 +55,9 @@ int virCgroupAddTask(virCgroupPtr group, pid_t pid);
int virCgroupSetBlkioWeight(virCgroupPtr group, unsigned int weight);
int virCgroupGetBlkioWeight(virCgroupPtr group, unsigned int *weight);
+int virCgroupSetBlkioWeightDevice(virCgroupPtr group, const char *weight_device);
+int virCgroupGetBlkioWeightDevice(virCgroupPtr group, char **weight_device);
+
int virCgroupSetMemory(virCgroupPtr group, unsigned long long kb);
int virCgroupGetMemoryUsage(virCgroupPtr group, unsigned long *kb);
diff --git a/tools/virsh.c b/tools/virsh.c
index 0f00463..8301efc 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -4557,6 +4557,8 @@ static const vshCmdOptDef opts_blkiotune[] = {
{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
{"weight", VSH_OT_INT, VSH_OFLAG_NONE,
N_("IO Weight in range [100, 1000]")},
+ {"weight-device", VSH_OT_STRING, VSH_OFLAG_NONE,
+ N_("per device IO Weight, in the form of major:minor,weight")},
{"config", VSH_OT_BOOL, 0, N_("affect next boot")},
{"live", VSH_OT_BOOL, 0, N_("affect running domain")},
{"current", VSH_OT_BOOL, 0, N_("affect current domain")},
@@ -4567,6 +4569,7 @@ static bool
cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
{
virDomainPtr dom;
+ const char *weight_device = NULL;
int weight = 0;
int nparams = 0;
int rv = 0;
@@ -4611,6 +4614,16 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
}
}
+ rv = vshCommandOptString(cmd, "weight-device", &weight_device);
+ if (rv < 0) {
+ vshError(ctl, "%s",
+ _("Unable to parse string parameter"));
+ goto cleanup;
+ }
+ if (rv > 0) {
+ nparams++;
+ }
+
if (nparams == 0) {
/* get the number of blkio parameters */
if (virDomainGetBlkioParameters(dom, NULL, &nparams, flags) != 0) {
@@ -4658,6 +4671,10 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
vshPrint(ctl, "%-15s: %d\n", params[i].field,
params[i].value.b);
break;
+ case VIR_TYPED_PARAM_STRING:
+ vshPrint(ctl, "%-15s: %s\n", params[i].field,
+ params[i].value.s);
+ break;
default:
vshPrint(ctl, "unimplemented blkio parameter type\n");
}
@@ -4678,6 +4695,20 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
sizeof(temp->field));
weight = 0;
}
+
+ if (weight_device) {
+ int len = strlen(weight_device) + 1;
+ temp->type = VIR_TYPED_PARAM_STRING;
+ temp->value.s = vshMalloc(ctl, len);
+ if (!temp->value.s) {
+ goto cleanup;
+ }
+ strncpy(temp->value.s, weight_device, strlen(weight_device));
+ temp->value.s[len-1] = '\0';
+ weight_device = NULL;
+ strncpy(temp->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE,
+ sizeof(temp->field));
+ }
}
if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0)
vshError(ctl, "%s", _("Unable to change blkio parameters"));
diff --git a/tools/virsh.pod b/tools/virsh.pod
index d826997..1f83237 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -976,12 +976,15 @@ value are kilobytes (i.e. blocks of 1024 bytes).
=back
-=item B<blkiotune> I<domain-id> [I<--weight> B<weight>] [[I<--config>]
+=item B<blkiotune> I<domain-id> [I<--weight> B<weight>]
+[I<--weight-device> B<weight-device>] [[I<--config>]
[I<--live>] | [I<--current>]]
Display or set the blkio parameters. QEMU/KVM supports I<--weight>.
I<--weight> is in range [100, 1000].
+B<weight-device> is in the format of major:minor,weight;major:minor,weight.
+
If I<--live> is specified, affect a running guest.
If I<--config> is specified, affect the next boot of a persistent guest.
If I<--current> is specified, affect the current guest state.
--
1.7.3.1
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