[libvirt] [PATCH v3 2/2] add interface for blkio.weight_device

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 | 114 ++++++++++++++++++++++++- src/conf/domain_conf.h | 16 ++++ src/libvirt_private.syms | 1 + src/qemu/qemu_cgroup.c | 22 +++++ src/qemu/qemu_driver.c | 191 +++++++++++++++++++++++++++++++++++++++++- src/util/cgroup.c | 33 +++++++ src/util/cgroup.h | 3 + tools/virsh.c | 52 ++++++++++-- tools/virsh.pod | 5 +- 11 files changed, 437 insertions(+), 14 deletions(-) diff --git a/daemon/remote.c b/daemon/remote.c index 82ee13b..bee1b94 100644 --- a/daemon/remote.c +++ b/daemon/remote.c @@ -1566,6 +1566,7 @@ remoteDispatchDomainGetBlkioParameters(virNetServerPtr server ATTRIBUTE_UNUSED, int nparams = args->nparams; unsigned int flags; int rv = -1; + int i; struct daemonClientPrivate *priv = virNetServerClientGetPrivateData(client); @@ -1610,6 +1611,10 @@ 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 448a0e7..a1f2c98 100644 --- a/include/libvirt/libvirt.h.in +++ b/include/libvirt/libvirt.h.in @@ -1139,6 +1139,15 @@ 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 7463d7c..75b17cd 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -566,6 +566,82 @@ 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 i; + virBuffer buf = VIR_BUFFER_INITIALIZER; + + for (i = 0; i < ndevices; i++) { + virBufferAsprintf(&buf, "%d:%d %d\n", + weightdevices[i].major, + weightdevices[i].minor, + weightdevices[i].weight); + } + + *result = virBufferContentAndReset(&buf); + return 0; +} + +/** + * virDomainBlkioWeightDeviceParseXML + * + * this function parses a XML node: + * + * <device> + * <path>/fully/qulaified/device/path</path> + * <weight>weight</weight> + * </device> + * + * and fills a virBlkioWeightDevice struct. + */ +static int virDomainBlkioWeightDeviceParseXML(xmlNodePtr root, + virBlkioWeightDevicePtr dw) +{ + char *c; + struct stat s; + xmlNodePtr node; + + if (!dw) + return -1; + + node = root->children; + while (node) { + if (node->type == XML_ELEMENT_NODE) { + if (xmlStrEqual(node->name, BAD_CAST "path")) { + c = (char *)xmlNodeGetContent(node); + if (!c) + return -1; + if (stat(c, &s) == -1) + return -1; + if ((s.st_mode & S_IFMT) == S_IFBLK) { + dw->major = major(s.st_rdev); + dw->minor = minor(s.st_rdev); + } else + return -1; + dw->path = (char *)xmlNodeGetContent(node); + } 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) { @@ -1230,6 +1306,8 @@ void virDomainDefFree(virDomainDefPtr def) VIR_FREE(def->emulator); VIR_FREE(def->description); + VIR_FREE(def->blkio.weight_devices); + virDomainWatchdogDefFree(def->watchdog); virDomainMemballoonDefFree(def->memballoon); @@ -6464,6 +6542,20 @@ 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) @@ -10499,10 +10591,26 @@ 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, " <path>%s</path>\n", + def->blkio.weight_devices[i].path); + 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..562c530 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1276,6 +1276,20 @@ struct _virDomainNumatuneDef { /* Future NUMA tuning related stuff should go here. */ }; +typedef struct _virBlkioWeightDevice virBlkioWeightDevice; +typedef virBlkioWeightDevice *virBlkioWeightDevicePtr; +struct _virBlkioWeightDevice { + int major; + int minor; + char *path; + int weight; +}; + +int virBlkioWeightDeviceToStr(virBlkioWeightDevicePtr deviceWeights, + int ndevices, + char **result); + + /* * Guest VM main configuration * @@ -1293,6 +1307,8 @@ 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 8235ea1..34ec488 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 0d0bea2..0d17ccd 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); @@ -5794,6 +5795,96 @@ cleanup: return ret; } +/* weightDeviceStr in the form of /device/path,weight;/device/path,weight + * for example, /dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0,800 + */ +static int parseBlkioWeightDeviceStr(const char *weightDeviceStr, virBlkioWeightDevicePtr *dw, int *size) +{ + struct stat s; + const char *temp; + int nDevice = 0; + int i, len; + 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; + + /* device path */ + + while (*p != ',' && *p != '\0') + ++p; + if (*p == '\0') + goto fail; + len = p - temp + 1; + if (VIR_ALLOC_N(result[i].path, len) < 0) + goto fail; + memcpy(result[i].path, temp, len - 1); + result[i].path[len - 1] = '\0'; + + if (stat(result[i].path, &s) == -1) { + VIR_FREE(result[i].path); + goto fail; + } + if ((s.st_mode & S_IFMT) != S_IFBLK) { + VIR_FREE(result[i].path); + goto fail; + } + result[i].major = major(s.st_rdev); + result[i].minor = minor(s.st_rdev); + + /* weight */ + + 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, @@ -5860,10 +5951,10 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom, ret = 0; if (flags & VIR_DOMAIN_AFFECT_LIVE) { for (i = 0; i < nparams; i++) { + int rc; virTypedParameterPtr param = &params[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'")); @@ -5884,6 +5975,44 @@ 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); @@ -5913,6 +6042,21 @@ 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); @@ -5946,9 +6090,11 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom, int ret = -1; int rc; bool isActive; + bool typed_string; virCheckFlags(VIR_DOMAIN_AFFECT_LIVE | - VIR_DOMAIN_AFFECT_CONFIG, -1); + VIR_DOMAIN_AFFECT_CONFIG | + VIR_DOMAIN_TYPED_STRING_OKAY, -1); qemuDriverLock(driver); vm = virDomainFindByUUID(&driver->domains, dom->uuid); @@ -5974,6 +6120,8 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom, isActive = virDomainObjIsActive(vm); + typed_string = (flags & VIR_DOMAIN_TYPED_STRING_OKAY) == VIR_DOMAIN_TYPED_STRING_OKAY; + flags &= ~VIR_DOMAIN_TYPED_STRING_OKAY; if (flags == VIR_DOMAIN_AFFECT_CURRENT) { if (isActive) flags = VIR_DOMAIN_AFFECT_LIVE; @@ -6012,6 +6160,7 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom, if (flags & VIR_DOMAIN_AFFECT_LIVE) { for (i = 0; i < *nparams; i++) { + char *weight_device; virTypedParameterPtr param = &params[i]; val = 0; param->value.ui = 0; @@ -6032,6 +6181,23 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom, } param->value.ui = val; break; + case 1: /* blkio.weight_device */ + if (typed_string) { + 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; @@ -6055,6 +6221,25 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom, param->value.ui = persistentDef->blkio.weight; break; + case 1: /* blkio.weight_device */ + if (typed_string) { + virBuffer buf = VIR_BUFFER_INITIALIZER; + for (i = 0; i < persistentDef->blkio.ndevices; i++) { + virBufferAsprintf(&buf, "%s %d\n", + persistentDef->blkio.weight_devices[i].path, + persistentDef->blkio.weight_devices[i].weight); + } + + param->value.s = virBufferContentAndReset(&buf); + 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 7b0533d..e79d9ae 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -4616,6 +4616,8 @@ 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")}, @@ -4626,6 +4628,7 @@ static bool cmdBlkiotune(vshControl * ctl, const vshCmd * cmd) { virDomainPtr dom; + const char *weight_device = NULL; int weight = 0; int nparams = 0; int rv = 0; @@ -4650,6 +4653,8 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd) flags |= VIR_DOMAIN_AFFECT_LIVE; } + flags |= VIR_DOMAIN_TYPED_STRING_OKAY; + if (!vshConnectionUsability(ctl, ctl->conn)) return false; @@ -4670,12 +4675,28 @@ 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 */ + /* old libvirtd doesn't understand VIR_DOMAIN_TYPED_STRING_OKAY, we + * give it a second try with this flag disabled in the case of an + * old libvirtd. */ if (virDomainGetBlkioParameters(dom, NULL, &nparams, flags) != 0) { - vshError(ctl, "%s", - _("Unable to get number of blkio parameters")); - goto cleanup; + flags &= ~VIR_DOMAIN_TYPED_STRING_OKAY; + if (virDomainGetBlkioParameters(dom, NULL, &nparams, flags) != 0) { + vshError(ctl, "%s", + _("Unable to get number of blkio parameters")); + goto cleanup; + } } if (nparams == 0) { @@ -4717,6 +4738,10 @@ 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"); } @@ -4737,11 +4762,24 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd) sizeof(temp->field)); weight = 0; } + + if (weight_device) { + virBuffer buf = VIR_BUFFER_INITIALIZER; + virBufferAsprintf(&buf, "%s", weight_device); + temp->value.s = virBufferContentAndReset(&buf); + temp->type = VIR_TYPED_PARAM_STRING; + strncpy(temp->field, VIR_DOMAIN_BLKIO_WEIGHT_DEVICE, + sizeof(temp->field)); + } + } + ret = true; + if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0) { + flags &= ~VIR_DOMAIN_TYPED_STRING_OKAY; + if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0) { + vshError(ctl, "%s", _("Unable to change blkio parameters")); + ret = false; + } } - if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0) - vshError(ctl, "%s", _("Unable to change blkio parameters")); - else - ret = true; } cleanup: diff --git a/tools/virsh.pod b/tools/virsh.pod index 086fe93..c0b2af0 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -1000,12 +1000,15 @@ value are kilobytes (i.e. blocks of 1024 bytes). Specifying -1 as a value for these limits is interpreted as unlimited. -=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 /device/patch,weight;/device/patch,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