1:06 p.m.
This adds per-device weights to <blkiotune>. Note that the
cgroups implementation only supports weights per block device,
and not per-file within the device; hence this option must be
global to the domain definition rather than tied to individual
<device>/<disk> entries:
<domain ...>
<blkiotune>
<device>
<path>/path/to/block</path>
<weight>1000</weight>
</device>
</blkiotune>
...
This patch also adds a parameter --device-weight to virsh command
blkiotune for setting/getting blkiotune.weight_device for any
hypervisor that supports it. All <device> entries under
<blkiotune> are concatenated into a single string attribute under
virDomain{Get,Set}BlkioParameters, named "device_weight".
---
v5: did not include this patch
v6: split v4 2/2 into two parts; this part covers just the libvirt.h
and virsh changes. Rename public-facing terminology to be
"device_weight", not "weight_device", since we are talking about
per-device weights and may later add other per-device attributes
(no need to propagate cgroups' stupid naming to the user). Rebase
to fit in with VIR_TYPED_PARAM_STRING tweaks earlier in series.
Should we use just commas for field separation, rather than commas
between device and weight but semicolon between device-weight pairs?
It would make it much easier to do:
virsh blkiotune dom --device-weight /dev/sda,500,/dev/sdb,500
instead of requiring shell quoting:
virsh blkiotune dom --device-weight '/dev/sda,500;/dev/sdb,500'
docs/formatdomain.html.in | 29 ++++++++-
docs/schemas/domaincommon.rng | 12 ++++
include/libvirt/libvirt.h.in | 10 +++
src/conf/domain_conf.c | 130 ++++++++++++++++++++++++++++++++++++++++-
src/conf/domain_conf.h | 17 +++++
src/libvirt_private.syms | 2 +
tools/virsh.c | 32 +++++++++-
tools/virsh.pod | 6 ++-
8 files changed, 228 insertions(+), 10 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index cbad196..e848b7d 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -505,6 +505,14 @@
...
<blkiotune>
<weight>800</weight>
+ <device>
+ <path>/dev/sda</path>
+ <weight>1000</weight>
+ </device>
+ <device>
+ <path>/dev/sdb</path>
+ <weight>500</weight>
+ </device>
</blkiotune>
...
</domain>
@@ -514,10 +522,25 @@
<dt><code>blkiotune</code></dt>
<dd> The optional <code>blkiotune</code> element provides the
ability
to tune Blkio cgroup tunable parameters for the domain. If this is
- omitted, it defaults to the OS provided defaults.</dd>
+ omitted, it defaults to the OS provided
+ defaults. <span class="since">Since
0.8.8</span></dd>
<dt><code>weight</code></dt>
- <dd> The optional <code>weight</code> element is the I/O weight
of the
- guest. The value should be in range [100, 1000].</dd>
+ <dd> The optional <code>weight</code> element is the overall I/O
+ weight of the guest. The value should be in the range [100,
+ 1000].</dd>
+ <dt><code>device</code></dt>
+ <dd>The domain may have multiple <code>device</code> elements
+ that further tune the weights for each host block device in
+ use by the domain. Note that
+ multiple <a href="#elementsDisks">guest disks</a> can share
a
+ single host block device, if they are backed by files within
+ the same host file system, which is why this tuning parameter
+ is at the global domain level rather than associated with each
+ guest disk device. Each <code>device</code> element has two
+ mandatory sub-elements, <code>path</code> describing the
+ absolute path of the device, and <code>weight</code> giving
+ the relative weight of that device, in the range [100,
+ 1000]. <span class="since">Since 0.9.7</span></dd>
</dl>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index b6f858e..6f96fe2 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -328,6 +328,18 @@
<ref name="weight"/>
</element>
</optional>
+ <zeroOrMore>
+ <element name="device">
+ <interleave>
+ <element name="path">
+ <ref name="absFilePath"/>
+ </element>
+ <element name="weight">
+ <data type="int"/>
+ </element>
+ </interleave>
+ </element>
+ </zeroOrMore>
</element>
</optional>
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index e10a72b..5ae7d10 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -1236,6 +1236,16 @@ char * virDomainGetSchedulerType(virDomainPtr
domain,
#define VIR_DOMAIN_BLKIO_WEIGHT "weight"
+/**
+ * VIR_DOMAIN_BLKIO_DEVICE_WEIGHT:
+ *
+ * Macro for the blkio tunable weight_device: it represents the
+ * per-device weight, as a string. The string is parsed as a
+ * series of /path/to/device,weight elements, separated by ';'.
+ */
+
+#define VIR_DOMAIN_BLKIO_DEVICE_WEIGHT "device_weight"
+
/* 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 238edfd..e5b5f69 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -603,6 +603,99 @@ VIR_ENUM_IMPL(virDomainStartupPolicy,
VIR_DOMAIN_STARTUP_POLICY_LAST,
#define VIR_DOMAIN_XML_WRITE_FLAGS VIR_DOMAIN_XML_SECURE
#define VIR_DOMAIN_XML_READ_FLAGS VIR_DOMAIN_XML_INACTIVE
+
+void virBlkioDeviceWeightArrayClear(virBlkioDeviceWeightPtr deviceWeights,
+ int ndevices)
+{
+ int i;
+
+ for (i = 0; i < ndevices; i++)
+ VIR_FREE(deviceWeights[i].path);
+}
+
+/**
+ * virBlkioDeviceWeightToStr:
+ *
+ * This function returns a string representing device weights that is
+ * suitable for writing to /cgroup/blkio/blkio.weight_device, given
+ * a list of per-device weights.
+ */
+#if defined(major) && defined(minor)
+int virBlkioDeviceWeightToStr(virBlkioDeviceWeightPtr devices,
+ int ndevices,
+ char **result)
+{
+ int i;
+ struct stat s;
+ virBuffer buf = VIR_BUFFER_INITIALIZER;
+
+ for (i = 0; i < ndevices; i++) {
+ if (stat(devices[i].path, &s) == -1)
+ return -1;
+ if ((s.st_mode & S_IFMT) != S_IFBLK)
+ return -1;
+ virBufferAsprintf(&buf, "%d:%d %d\n",
+ major(s.st_rdev),
+ minor(s.st_rdev),
+ devices[i].weight);
+ }
+
+ if (virBufferError(&buf))
+ return -1;
+
+ *result = virBufferContentAndReset(&buf);
+ return 0;
+}
+#else
+int virBlkioDeviceWeightToStr(virBlkioDeviceWeightPtr devices ATTRIBUTE_UNUSED,
+ int ndevices ATTRIBUTE_UNUSED,
+ char **result ATTRIBUTE_UNUSED)
+{
+ return -1;
+}
+#endif
+
+/**
+ * virDomainBlkioDeviceWeightParseXML
+ *
+ * this function parses a XML node:
+ *
+ * <device>
+ * <path>/fully/qualified/device/path</path>
+ * <weight>weight</weight>
+ * </device>
+ *
+ * and fills a virBlkioDeviceWeight struct.
+ */
+static int virDomainBlkioDeviceWeightParseXML(xmlNodePtr root,
+ virBlkioDeviceWeightPtr 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 "path")) {
+ dw->path = (char *)xmlNodeGetContent(node);
+ } else if (xmlStrEqual(node->name, BAD_CAST "weight")) {
+ c = (char *)xmlNodeGetContent(node);
+ if (virStrToLong_i(c, NULL, 10, &dw->weight) < 0)
+ return -1;
+ VIR_FREE(c);
+ }
+ }
+ node = node->next;
+ }
+
+ return 0;
+}
+
+
+
static void
virDomainObjListDataFree(void *payload, const void *name ATTRIBUTE_UNUSED)
{
@@ -1272,6 +1365,10 @@ void virDomainDefFree(virDomainDefPtr def)
VIR_FREE(def->emulator);
VIR_FREE(def->description);
+ virBlkioDeviceWeightArrayClear(def->blkio.devices,
+ def->blkio.ndevices);
+ VIR_FREE(def->blkio.devices);
+
virDomainWatchdogDefFree(def->watchdog);
virDomainMemballoonDefFree(def->memballoon);
@@ -6710,6 +6807,21 @@ 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.devices, n) < 0) {
+ virReportOOMError();
+ goto error;
+ }
+
+ for (i = 0; i < n; i++) {
+ virDomainBlkioDeviceWeightParseXML(nodes[i],
+ &def->blkio.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)
@@ -10848,10 +10960,22 @@ virDomainDefFormatInternal(virDomainDefPtr def,
def->mem.cur_balloon);
/* add blkiotune only if there are any */
- if (def->blkio.weight) {
+ if (def->blkio.weight || def->blkio.devices) {
virBufferAddLit(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);
+
+ for (n = 0; n < def->blkio.ndevices; n++) {
+ virBufferAddLit(buf, " <device>\n");
+ virBufferEscapeString(buf, " <path>%s</path>\n",
+ def->blkio.devices[n].path);
+ virBufferAsprintf(buf, " <weight>%d</weight>\n",
+ def->blkio.devices[n].weight);
+ virBufferAddLit(buf, " </device>\n");
+ }
+
virBufferAddLit(buf, " </blkiotune>\n");
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 5ebb441..577d10d 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1361,6 +1361,20 @@ struct _virDomainNumatuneDef {
/* Future NUMA tuning related stuff should go here. */
};
+typedef struct _virBlkioDeviceWeight virBlkioDeviceWeight;
+typedef virBlkioDeviceWeight *virBlkioDeviceWeightPtr;
+struct _virBlkioDeviceWeight {
+ char *path;
+ int weight;
+};
+
+void virBlkioDeviceWeightArrayClear(virBlkioDeviceWeightPtr deviceWeights,
+ int ndevices);
+int virBlkioDeviceWeightToStr(virBlkioDeviceWeightPtr deviceWeights,
+ int ndevices,
+ char **result);
+
+
/*
* Guest VM main configuration
*
@@ -1378,6 +1392,9 @@ struct _virDomainDef {
struct {
unsigned int weight;
+
+ size_t ndevices;
+ virBlkioDeviceWeightPtr devices;
} blkio;
struct {
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 2185294..f7d0fb2 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -231,6 +231,8 @@ virDomainAuditVcpu;
# domain_conf.h
+virBlkioDeviceWeightArrayClear;
+virBlkioDeviceWeightToStr;
virDiskNameToBusDeviceIndex;
virDiskNameToIndex;
virDomainActualNetDefFree;
diff --git a/tools/virsh.c b/tools/virsh.c
index 5544a41..ca8db70 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -4648,6 +4648,8 @@ 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]")},
+ {"device-weight", VSH_OT_STRING, VSH_OFLAG_NONE,
+ N_("per-device IO Weights, in the form of /path/to/device,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")},
@@ -4658,6 +4660,7 @@ static bool
cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
{
virDomainPtr dom;
+ const char *device_weight = NULL;
int weight = 0;
int nparams = 0;
int rv = 0;
@@ -4702,6 +4705,16 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
}
}
+ rv = vshCommandOptString(cmd, "device-weight", &device_weight);
+ 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) {
@@ -4749,6 +4762,10 @@ 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");
}
@@ -4769,11 +4786,20 @@ cmdBlkiotune(vshControl * ctl, const vshCmd * cmd)
sizeof(temp->field));
weight = 0;
}
+
+ if (device_weight) {
+ /* Safe to cast away const here. */
+ temp->value.s = (char *)device_weight;
+ temp->type = VIR_TYPED_PARAM_STRING;
+ strncpy(temp->field, VIR_DOMAIN_BLKIO_DEVICE_WEIGHT,
+ sizeof(temp->field));
+ }
}
- if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0)
+ ret = true;
+ if (virDomainSetBlkioParameters(dom, params, nparams, flags) != 0) {
vshError(ctl, "%s", _("Unable to change blkio
parameters"));
- else
- ret = true;
+ ret = false;
+ }
}
cleanup:
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 775d302..a117e84 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1032,12 +1032,16 @@ 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<--device-weight> B<device-weights>] [[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<device-weights> is a single string listing one or more device/weight
+pairs, in the format of /path/to/device,weight;/path/to/device,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.
--
1.7.4.4