[libvirt] [PATCHv4 4/4] blkiotune: add qemu support for blkiotune.device_weight
Hu Tao
hutao at cn.fujitsu.com
Tue Nov 15 07:22:03 UTC 2011
On Mon, Nov 14, 2011 at 09:30:02PM -0700, Eric Blake wrote:
> From: Hu Tao <hutao at cn.fujitsu.com>
>
> Implement setting/getting per-device blkio weights in qemu,
> using the cgroups blkio.weight_device tunable.
> ---
> src/libvirt_private.syms | 1 +
> src/qemu/qemu_cgroup.c | 20 ++
> src/qemu/qemu_driver.c | 218 +++++++++++++++++++-
> src/util/cgroup.c | 51 +++++
> src/util/cgroup.h | 4 +
> .../qemuxml2argv-blkiotune-device.args | 4 +
> tests/qemuxml2argvtest.c | 1 +
> tests/qemuxml2xmltest.c | 1 +
> 8 files changed, 295 insertions(+), 5 deletions(-)
> create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-blkiotune-device.args
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index d78fd53..3575fe0 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -89,6 +89,7 @@ virCgroupKillRecursive;
> virCgroupMounted;
> virCgroupPathOfController;
> virCgroupRemove;
> +virCgroupSetBlkioDeviceWeight;
> virCgroupSetBlkioWeight;
> virCgroupSetCpuShares;
> virCgroupSetCpuCfsPeriod;
> diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
> index 2a10bd2..eda4c66 100644
> --- a/src/qemu/qemu_cgroup.c
> +++ b/src/qemu/qemu_cgroup.c
> @@ -312,6 +312,26 @@ int qemuSetupCgroup(struct qemud_driver *driver,
> }
> }
>
> + 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"));
> + }
> + }
> +
> 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 b0ce115..43f4041 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -112,7 +112,7 @@
> # 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);
>
> @@ -5885,6 +5885,105 @@ cleanup:
> return ret;
> }
>
> +/* deviceWeightStr 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(char *deviceWeightStr,
> + virBlkioDeviceWeightPtr *dw, int *size,
> + virCgroupPtr cgroup)
> +{
> + char *temp;
> + int ndevices = 0;
> + int nsep = 0;
> + int i;
> + virBlkioDeviceWeightPtr result = NULL;
> +
> + temp = deviceWeightStr;
> + while (temp) {
> + temp = strchr(temp, ',');
> + if (temp) {
> + temp++;
> + nsep++;
> + }
> + }
> +
> + /* A valid string must have even number of fields, hence an odd
> + * number of commas. */
> + if (!(nsep & 1))
> + goto error;
> +
> + ndevices = (nsep + 1) / 2;
> +
> + if (VIR_ALLOC_N(result, ndevices) < 0) {
> + virReportOOMError();
> + return -1;
> + }
> +
> + i = 0;
> + temp = deviceWeightStr;
> + while (temp) {
> + char *p = temp;
> +
> + /* device path */
> + p = strchr(p, ',');
> + if (!p)
> + goto error;
> +
> + result[i].path = strndup(temp, p - temp);
> + if (!result[i].path) {
> + virReportOOMError();
> + goto cleanup;
> + }
> +
> + /* weight */
> + temp = p + 1;
> +
> + if (virStrToLong_ui(temp, &p, 10, &result[i].weight) < 0)
> + goto error;
> +
> + if (cgroup) {
> + int rc = virCgroupSetBlkioDeviceWeight(cgroup,
> + result[i].path,
> + result[i].weight);
Does more than the function name says. Would it be better to just do the
parsing here, and set the cgroup values after parsing(see my comment to
patch 3 for filtering out 0-weight when writing to xml):
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 43f4041..275d5c8 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5890,8 +5890,7 @@ cleanup:
*/
static int
parseBlkioWeightDeviceStr(char *deviceWeightStr,
- virBlkioDeviceWeightPtr *dw, int *size,
- virCgroupPtr cgroup)
+ virBlkioDeviceWeightPtr *dw, int *size)
{
char *temp;
int ndevices = 0;
@@ -5942,24 +5941,8 @@ parseBlkioWeightDeviceStr(char *deviceWeightStr,
if (virStrToLong_ui(temp, &p, 10, &result[i].weight) < 0)
goto error;
- if (cgroup) {
- int rc = virCgroupSetBlkioDeviceWeight(cgroup,
- result[i].path,
- result[i].weight);
- if (rc < 0) {
- virReportSystemError(-rc,
- _("Unable to set io device weight "
- "for path %s"),
- result[i].path);
- goto cleanup;
- }
- }
+ i++;
- /* 0-weight entries only affect cgroups, they don't stick in xml */
- if (result[i].weight)
- i++;
- else
- VIR_FREE(result[i].path);
if (*p == '\0')
break;
else if (*p != ',')
@@ -6087,7 +6070,23 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
if (parseBlkioWeightDeviceStr(params[i].value.s,
&devices,
- &ndevices, group) < 0) {
+ &ndevices) < 0) {
+ ret = -1;
+ continue;
+ }
+ for (i = 0; i < ndevices; i++) {
+ rc = virCgroupSetBlkioDeviceWeight(group,
+ devices[i].path,
+ devices[i].weight);
+ if (rc < 0) {
+ virReportSystemError(-rc,
+ _("Unable to set io device weight "
+ "for path %s"),
+ devices[i].path);
+ break;
+ }
+ }
+ if (i != ndevices) {
ret = -1;
continue;
}
@@ -6140,7 +6139,7 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
}
if (parseBlkioWeightDeviceStr(params[i].value.s,
&devices,
- &ndevices, NULL) < 0) {
+ &ndevices) < 0) {
ret = -1;
continue;
}
--
Thanks,
Hu Tao
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