Busy enterprise workloads hosted on large sized VM's tend to dirty
memory faster than the transfer rate achieved via live guest migration.
Despite some good recent improvements (& using dedicated 10Gig NICs
between hosts) the live migration may NOT converge.
Recently support was added in qemu (version 1.6) to allow a user to
choose if they wish to force convergence of their migration via a
new migration capability : "auto-converge". This feature allows for qemu
to auto-detect lack of convergence and trigger a throttle-down of the
VCPUs.
This RFC patch includes the libvirt support needed to trigger this
feature. (Testing is still in progress)
Signed-off-by: Chegu Vinod <chegu_vinod@xxxxxx>
---
include/libvirt/libvirt.h.in | 1 +
src/qemu/qemu_migration.c | 44 ++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_migration.h | 1 +
src/qemu/qemu_monitor.c | 2 +-
src/qemu/qemu_monitor.h | 1 +
tools/virsh-domain.c | 7 ++++++
6 files changed, 55 insertions(+), 1 deletions(-)
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index 146a59b..13b0bfc 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -1192,6 +1192,7 @@ typedef enum {
VIR_MIGRATE_OFFLINE = (1 << 10), /* offline migrate */
VIR_MIGRATE_COMPRESSED = (1 << 11), /* compress data during migration */
VIR_MIGRATE_ABORT_ON_ERROR = (1 << 12), /* abort migration on I/O errors happened during migration */
+ VIR_MIGRATE_AUTO_CONVERGE = (1 << 13), /* force auto-convergence during during migration */
} virDomainMigrateFlags;
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index e87ea85..8cc0c56 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1565,6 +1565,40 @@ cleanup:
}
static int
+qemuMigrationSetAutoConverge(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ enum qemuDomainAsyncJob job)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ int ret;
+
+ if (qemuDomainObjEnterMonitorAsync(driver, vm, job) < 0)
+ return -1;
+
+ ret = qemuMonitorGetMigrationCapability(
+ priv->mon,
+ QEMU_MONITOR_MIGRATION_CAPS_AUTO_CONVERGE);
+
+ if (ret < 0) {
+ goto cleanup;
+ } else if (ret == 0) {
+ virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
+ _("Auto-Converge migration is not supported by "
+ "QEMU binary"));
+ ret = -1;
+ goto cleanup;
+ }
+
+ ret = qemuMonitorSetMigrationCapability(
+ priv->mon,
+ QEMU_MONITOR_MIGRATION_CAPS_AUTO_CONVERGE);
+
+cleanup:
+ qemuDomainObjExitMonitor(driver, vm);
+ return ret;
+}
+
+static int
qemuMigrationWaitForSpice(virQEMUDriverPtr driver,
virDomainObjPtr vm)
{
@@ -2389,6 +2423,11 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
goto stop;
+ if (flags & VIR_MIGRATE_AUTO_CONVERGE &&
+ qemuMigrationSetAutoConverge(driver, vm,
+ QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
+ goto stop;
+
if (mig->lockState) {
VIR_DEBUG("Received lockstate %s", mig->lockState);
VIR_FREE(priv->lockState);
@@ -3181,6 +3220,11 @@ qemuMigrationRun(virQEMUDriverPtr driver,
QEMU_ASYNC_JOB_MIGRATION_OUT) < 0)
goto cleanup;
+ if (flags & VIR_MIGRATE_AUTO_CONVERGE &&
+ qemuMigrationSetAutoConverge(driver, vm,
+ QEMU_ASYNC_JOB_MIGRATION_OUT) < 0)
+ goto cleanup;
+
if (qemuDomainObjEnterMonitorAsync(driver, vm,
QEMU_ASYNC_JOB_MIGRATION_OUT) < 0)
goto cleanup;
diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h
index cafa2a2..c4258a1 100644
--- a/src/qemu/qemu_migration.h
+++ b/src/qemu/qemu_migration.h
@@ -39,6 +39,7 @@
VIR_MIGRATE_UNSAFE | \
VIR_MIGRATE_OFFLINE | \
VIR_MIGRATE_COMPRESSED | \
+ VIR_MIGRATE_AUTO_CONVERGE | \
VIR_MIGRATE_ABORT_ON_ERROR)
/* All supported migration parameters and their types. */
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 1514715..780a29a 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -118,7 +118,7 @@ VIR_ENUM_IMPL(qemuMonitorMigrationStatus,
VIR_ENUM_IMPL(qemuMonitorMigrationCaps,
QEMU_MONITOR_MIGRATION_CAPS_LAST,
- "xbzrle")
+ "xbzrle", "auto-converge")
VIR_ENUM_IMPL(qemuMonitorVMStatus,
QEMU_MONITOR_VM_STATUS_LAST,
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index eabf000..95e70ab 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -440,6 +440,7 @@ int qemuMonitorGetSpiceMigrationStatus(qemuMonitorPtr mon,
typedef enum {
QEMU_MONITOR_MIGRATION_CAPS_XBZRLE,
+ QEMU_MONITOR_MIGRATION_CAPS_AUTO_CONVERGE,
QEMU_MONITOR_MIGRATION_CAPS_LAST
} qemuMonitorMigrationCaps;
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 1fe138c..d94a81b 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -8532,6 +8532,10 @@ static const vshCmdOptDef opts_migrate[] = {
.type = VSH_OT_BOOL,
.help = N_("compress repeated pages during live migration")
},
+ {.name = "auto-converge",
+ .type = VSH_OT_BOOL,
+ .help = N_("force auto convergence during live migration")
+ },
{.name = "abort-on-error",
.type = VSH_OT_BOOL,
.help = N_("abort on soft errors during migration")
@@ -8676,6 +8680,9 @@ doMigrate(void *opaque)
if (vshCommandOptBool(cmd, "compressed"))
flags |= VIR_MIGRATE_COMPRESSED;
+ if (vshCommandOptBool(cmd, "auto-converge"))
+ flags |= VIR_MIGRATE_AUTO_CONVERGE;
+
if (vshCommandOptBool(cmd, "offline")) {
flags |= VIR_MIGRATE_OFFLINE;
}
--
1.7.1
--
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