The new 'VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES' migration
parameter allows users of migration to pass in a list of disks where
zero-detection (which avoids transferring the zeroed-blocks) should be
enabled for the migration connection. This comes at the cost of extra
CPU cycles needed to check each block if it's all-zero.
This is useful for storage backends where information about the
allocation state of a block is not available and thus without this the
image would become fully allocated on the destination.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
---
include/libvirt/libvirt-domain.h | 13 ++++
src/qemu/qemu_driver.c | 20 ++++--
src/qemu/qemu_migration.c | 105 +++++++++++++++++++++++--------
src/qemu/qemu_migration.h | 4 ++
4 files changed, 110 insertions(+), 32 deletions(-)
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 4266237abe..6d4cc69c5d 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -1240,6 +1240,19 @@ typedef enum {
*/
# define VIR_MIGRATE_PARAM_MIGRATE_DISKS "migrate_disks"
+/**
+ * VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES:
+ *
+ * virDomainMigrate* params multiple field: The multiple values that list
+ * the block devices for which zero detection (to avoid transferring zero blocks)
+ * is to be enabled. This may increase CPU overhead of the migration. At the
+ * moment this is only supported by the QEMU driver but not for the tunnelled
+ * migration.
+ *
+ * Since: 10.9.0
+ */
+# define VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES "migrate_disks_detect_zeroes"
+
/**
* VIR_MIGRATE_PARAM_DISKS_PORT:
*
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index cec700a36c..472bcd1fd3 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -10782,7 +10782,7 @@ qemuDomainMigratePerform(virDomainPtr dom,
* Consume any cookie we were able to decode though
*/
ret = qemuMigrationSrcPerform(driver, dom->conn, vm, NULL,
- NULL, dconnuri, uri, NULL, NULL, NULL, 0,
+ NULL, dconnuri, uri, NULL, NULL, NULL, NULL, 0,
NULL,
migParams, cookie, cookielen,
NULL, NULL, /* No output cookies in v2 */
@@ -10858,7 +10858,7 @@ qemuDomainMigrateBegin3(virDomainPtr domain,
}
return qemuMigrationSrcBegin(domain->conn, vm, xmlin, dname,
- cookieout, cookieoutlen, NULL, flags);
+ cookieout, cookieoutlen, NULL, NULL, flags);
}
static char *
@@ -10872,6 +10872,7 @@ qemuDomainMigrateBegin3Params(virDomainPtr domain,
const char *xmlin = NULL;
const char *dname = NULL;
g_autofree const char **migrate_disks = NULL;
+ g_autofree const char **migrate_disks_detect_zeroes = NULL;
virDomainObj *vm;
virCheckFlags(QEMU_MIGRATION_FLAGS, NULL);
@@ -10889,6 +10890,10 @@ qemuDomainMigrateBegin3Params(virDomainPtr domain,
virTypedParamsGetStringList(params, nparams, VIR_MIGRATE_PARAM_MIGRATE_DISKS,
&migrate_disks);
+ virTypedParamsGetStringList(params, nparams,
+ VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES,
+ &migrate_disks_detect_zeroes);
+
if (!(vm = qemuDomainObjFromDomain(domain)))
return NULL;
@@ -10899,7 +10904,8 @@ qemuDomainMigrateBegin3Params(virDomainPtr domain,
return qemuMigrationSrcBegin(domain->conn, vm, xmlin, dname,
cookieout, cookieoutlen,
- migrate_disks, flags);
+ migrate_disks, migrate_disks_detect_zeroes,
+ flags);
}
@@ -11180,7 +11186,7 @@ qemuDomainMigratePerform3(virDomainPtr dom,
goto cleanup;
ret = qemuMigrationSrcPerform(driver, dom->conn, vm, xmlin, NULL,
- dconnuri, uri, NULL, NULL, NULL, 0,
+ dconnuri, uri, NULL, NULL, NULL, NULL, 0,
NULL, migParams,
cookiein, cookieinlen,
cookieout, cookieoutlen,
@@ -11211,6 +11217,7 @@ qemuDomainMigratePerform3Params(virDomainPtr dom,
const char *graphicsuri = NULL;
const char *listenAddress = NULL;
g_autofree const char **migrate_disks = NULL;
+ g_autofree const char **migrate_disks_detect_zeroes = NULL;
unsigned long long bandwidth = 0;
int nbdPort = 0;
g_autoptr(qemuMigrationParams) migParams = NULL;
@@ -11267,6 +11274,9 @@ qemuDomainMigratePerform3Params(virDomainPtr dom,
virTypedParamsGetStringList(params, nparams, VIR_MIGRATE_PARAM_MIGRATE_DISKS,
&migrate_disks);
+ virTypedParamsGetStringList(params, nparams,
+ VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES,
+ &migrate_disks_detect_zeroes);
if (flags & (VIR_MIGRATE_NON_SHARED_DISK | VIR_MIGRATE_NON_SHARED_INC) ||
migrate_disks) {
@@ -11289,7 +11299,7 @@ qemuDomainMigratePerform3Params(virDomainPtr dom,
ret = qemuMigrationSrcPerform(driver, dom->conn, vm, dom_xml, persist_xml,
dconnuri, uri, graphicsuri, listenAddress,
- migrate_disks, nbdPort,
+ migrate_disks, migrate_disks_detect_zeroes, nbdPort,
nbdURI, migParams,
cookiein, cookieinlen, cookieout, cookieoutlen,
flags, dname, bandwidth, true);
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 94636e778d..7ae19dd0ce 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1022,7 +1022,8 @@ qemuMigrationSrcNBDStorageCopyBlockdevPrepareSource(virDomainDiskDef *disk,
int port,
const char *socket,
const char *tlsAlias,
- const char *tlsHostname)
+ const char *tlsHostname,
+ bool detect_zeroes)
{
g_autoptr(virStorageSource) copysrc = NULL;
@@ -1031,6 +1032,9 @@ qemuMigrationSrcNBDStorageCopyBlockdevPrepareSource(virDomainDiskDef *disk,
copysrc->protocol = VIR_STORAGE_NET_PROTOCOL_NBD;
copysrc->format = VIR_STORAGE_FILE_RAW;
+ if (detect_zeroes)
+ copysrc->detect_zeroes = VIR_DOMAIN_DISK_DETECT_ZEROES_ON;
+
copysrc->backingStore = virStorageSourceNew();
if (!(copysrc->path = qemuAliasDiskDriveFromDisk(disk)))
@@ -1067,7 +1071,8 @@ qemuMigrationSrcNBDStorageCopyBlockdev(virDomainObj *vm,
unsigned int mirror_shallow,
const char *tlsAlias,
const char *tlsHostname,
- bool syncWrites)
+ bool syncWrites,
+ bool detect_zeroes)
{
g_autoptr(qemuBlockStorageSourceAttachData) data = NULL;
qemuDomainDiskPrivate *diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
@@ -1081,7 +1086,8 @@ qemuMigrationSrcNBDStorageCopyBlockdev(virDomainObj *vm,
VIR_DEBUG("starting blockdev mirror for disk=%s to host=%s", disk->dst, host);
if (!(copysrc = qemuMigrationSrcNBDStorageCopyBlockdevPrepareSource(disk, host, port, socket,
- tlsAlias, tlsHostname)))
+ tlsAlias, tlsHostname,
+ detect_zeroes)))
return -1;
if (!(data = qemuBlockStorageSourceAttachPrepareBlockdev(copysrc,
@@ -1123,6 +1129,7 @@ qemuMigrationSrcNBDStorageCopyOne(virDomainObj *vm,
bool mirror_shallow,
const char *tlsAlias,
const char *tlsHostname,
+ bool detect_zeroes,
unsigned int flags)
{
qemuDomainDiskPrivate *diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
@@ -1147,7 +1154,8 @@ qemuMigrationSrcNBDStorageCopyOne(virDomainObj *vm,
mirror_shallow,
tlsAlias,
tlsHostname,
- syncWrites);
+ syncWrites,
+ detect_zeroes);
if (rc == 0) {
diskPriv->migrating = true;
@@ -1183,6 +1191,7 @@ qemuMigrationSrcNBDStorageCopy(virQEMUDriver *driver,
const char *host,
unsigned long speed,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
virConnectPtr dconn,
const char *tlsAlias,
const char *tlsHostname,
@@ -1254,15 +1263,20 @@ qemuMigrationSrcNBDStorageCopy(virQEMUDriver *driver,
for (i = 0; i < vm->def->ndisks; i++) {
virDomainDiskDef *disk = vm->def->disks[i];
+ bool detect_zeroes = false;
/* check whether disk should be migrated */
if (!qemuMigrationAnyCopyDisk(disk, migrate_disks))
continue;
+ if (migrate_disks_detect_zeroes)
+ detect_zeroes = g_strv_contains(migrate_disks_detect_zeroes, disk->dst);
+
if (qemuMigrationSrcNBDStorageCopyOne(vm, disk, host, port,
socket,
mirror_speed, mirror_shallow,
- tlsAlias, tlsHostname, flags) < 0)
+ tlsAlias, tlsHostname, detect_zeroes,
+ flags) < 0)
return -1;
if (virDomainObjSave(vm, driver->xmlopt, cfg->stateDir) < 0) {
@@ -2607,6 +2621,7 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver,
char **cookieout,
int *cookieoutlen,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
unsigned int flags)
{
qemuDomainObjPrivate *priv = vm->privateData;
@@ -2614,10 +2629,10 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver,
VIR_DEBUG("driver=%p, vm=%p, xmlin=%s, dname=%s,"
" cookieout=%p, cookieoutlen=%p,"
- " migrate_disks=%p, flags=0x%x",
+ " migrate_disks=%p, migrate_disks_detect_zeroes=%p, flags=0x%x",
driver, vm, NULLSTR(xmlin), NULLSTR(dname),
cookieout, cookieoutlen,
- migrate_disks, flags);
+ migrate_disks, migrate_disks_detect_zeroes, flags);
/* Only set the phase if we are inside VIR_ASYNC_JOB_MIGRATION_OUT.
* Otherwise we will start the async job later in the perform phase losing
@@ -2684,6 +2699,10 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver,
qemuMigrationSrcBeginPhaseValidateDiskTargetList(vm, migrate_disks) < 0)
return NULL;
+ if (migrate_disks_detect_zeroes &&
+ qemuMigrationSrcBeginPhaseValidateDiskTargetList(vm, migrate_disks_detect_zeroes) < 0)
+ return NULL;
+
priv->nbdPort = 0;
if (qemuMigrationHasAnyStorageMigrationDisks(vm->def, migrate_disks))
@@ -2694,6 +2713,13 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver,
_("use of 'VIR_MIGRATE_PARAM_MIGRATE_DISKS' requires use of 'VIR_MIGRATE_NON_SHARED_DISK' or 'VIR_MIGRATE_NON_SHARED_INC' flag"));
return NULL;
}
+
+ if (migrate_disks_detect_zeroes) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("use of 'VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES' requires use of 'VIR_MIGRATE_NON_SHARED_DISK' or 'VIR_MIGRATE_NON_SHARED_INC' flag"));
+ return NULL;
+ }
+
}
if (virDomainDefHasMemoryHotplug(vm->def) ||
@@ -2844,6 +2870,7 @@ qemuMigrationSrcBegin(virConnectPtr conn,
char **cookieout,
int *cookieoutlen,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
unsigned int flags)
{
virQEMUDriver *driver = conn->privateData;
@@ -2893,7 +2920,9 @@ qemuMigrationSrcBegin(virConnectPtr conn,
if (!(xml = qemuMigrationSrcBeginPhase(driver, vm, xmlin, dname,
cookieout, cookieoutlen,
- migrate_disks, flags)))
+ migrate_disks,
+ migrate_disks_detect_zeroes,
+ flags)))
goto endjob;
if ((flags & VIR_MIGRATE_CHANGE_PROTECTION)) {
@@ -4740,6 +4769,7 @@ qemuMigrationSrcRun(virQEMUDriver *driver,
virConnectPtr dconn,
const char *graphicsuri,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
qemuMigrationParams *migParams,
const char *nbdURI)
{
@@ -4765,11 +4795,11 @@ qemuMigrationSrcRun(virQEMUDriver *driver,
VIR_DEBUG("driver=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
"cookieout=%p, cookieoutlen=%p, flags=0x%x, resource=%lu, "
"spec=%p (dest=%d, fwd=%d), dconn=%p, graphicsuri=%s, "
- "migrate_disks=%p",
+ "migrate_disks=%p, migrate_disks_detect_zeroes=%p",
driver, vm, NULLSTR(cookiein), cookieinlen,
cookieout, cookieoutlen, flags, resource,
spec, spec->destType, spec->fwdType, dconn,
- NULLSTR(graphicsuri), migrate_disks);
+ NULLSTR(graphicsuri), migrate_disks, migrate_disks_detect_zeroes);
if (storageMigration)
storageMigration = qemuMigrationHasAnyStorageMigrationDisks(vm->def,
@@ -4907,6 +4937,7 @@ qemuMigrationSrcRun(virQEMUDriver *driver,
host,
priv->migMaxBandwidth,
migrate_disks,
+ migrate_disks_detect_zeroes,
dconn, tlsAlias, tlsHostname,
nbdURI, flags) < 0) {
goto error;
@@ -5176,6 +5207,7 @@ qemuMigrationSrcPerformNative(virQEMUDriver *driver,
virConnectPtr dconn,
const char *graphicsuri,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
qemuMigrationParams *migParams,
const char *nbdURI)
{
@@ -5186,10 +5218,10 @@ qemuMigrationSrcPerformNative(virQEMUDriver *driver,
VIR_DEBUG("driver=%p, vm=%p, uri=%s, cookiein=%s, cookieinlen=%d, "
"cookieout=%p, cookieoutlen=%p, flags=0x%x, resource=%lu, "
- "graphicsuri=%s, migrate_disks=%p",
+ "graphicsuri=%s, migrate_disks=%p, migrate_disks_detect_zeroes=%p",
driver, vm, uri, NULLSTR(cookiein), cookieinlen,
cookieout, cookieoutlen, flags, resource,
- NULLSTR(graphicsuri), migrate_disks);
+ NULLSTR(graphicsuri), migrate_disks, migrate_disks_detect_zeroes);
if (!(uribits = qemuMigrationAnyParseURI(uri, NULL)))
return -1;
@@ -5255,7 +5287,7 @@ qemuMigrationSrcPerformNative(virQEMUDriver *driver,
ret = qemuMigrationSrcRun(driver, vm, xmlin, persist_xml, cookiein, cookieinlen,
cookieout, cookieoutlen, flags, resource,
&spec, dconn, graphicsuri,
- migrate_disks,
+ migrate_disks, migrate_disks_detect_zeroes,
migParams, nbdURI);
}
@@ -5316,9 +5348,11 @@ qemuMigrationSrcPerformTunnel(virQEMUDriver *driver,
goto cleanup;
}
+ /* Migration with NBD is not supported with _TUNNELED, thus
+ * 'migrate_disks_detect_zeroes' is NULL here */
ret = qemuMigrationSrcRun(driver, vm, xmlin, persist_xml, cookiein, cookieinlen,
cookieout, cookieoutlen, flags, resource, &spec,
- dconn, graphicsuri, migrate_disks,
+ dconn, graphicsuri, migrate_disks, NULL,
migParams, NULL);
cleanup:
@@ -5358,7 +5392,7 @@ qemuMigrationSrcPerformResume(virQEMUDriver *driver,
ret = qemuMigrationSrcPerformNative(driver, vm, NULL, NULL, uri,
cookiein, cookieinlen,
cookieout, cookieoutlen, flags,
- 0, NULL, NULL, NULL, migParams, NULL);
+ 0, NULL, NULL, NULL, NULL, migParams, NULL);
virCloseCallbacksDomainAdd(vm, conn, qemuMigrationAnyConnectionClosed);
@@ -5466,7 +5500,7 @@ qemuMigrationSrcPerformPeer2Peer2(virQEMUDriver *driver,
cookie, cookielen,
NULL, NULL, /* No out cookie with v2 migration */
flags, resource, dconn, NULL, NULL,
- migParams, NULL);
+ NULL, migParams, NULL);
/* Perform failed. Make sure Finish doesn't overwrite the error */
if (ret < 0)
@@ -5529,6 +5563,7 @@ qemuMigrationSrcPerformPeer2Peer3(virQEMUDriver *driver,
const char *graphicsuri,
const char *listenAddress,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
int nbdPort,
const char *nbdURI,
qemuMigrationParams *migParams,
@@ -5555,11 +5590,11 @@ qemuMigrationSrcPerformPeer2Peer3(virQEMUDriver *driver,
VIR_DEBUG("driver=%p, sconn=%p, dconn=%p, dconnuri=%s, vm=%p, xmlin=%s, "
"dname=%s, uri=%s, graphicsuri=%s, listenAddress=%s, "
- "migrate_disks=%p, nbdPort=%d, nbdURI=%s, "
+ "migrate_disks=%p, migrate_disks_detect_zeroes=%p, nbdPort=%d, nbdURI=%s, "
"bandwidth=%llu, useParams=%d, flags=0x%x",
driver, sconn, dconn, NULLSTR(dconnuri), vm, NULLSTR(xmlin),
NULLSTR(dname), NULLSTR(uri), NULLSTR(graphicsuri),
- NULLSTR(listenAddress), migrate_disks, nbdPort,
+ NULLSTR(listenAddress), migrate_disks, migrate_disks_detect_zeroes, nbdPort,
NULLSTR(nbdURI), bandwidth, useParams, flags);
/* Unlike the virDomainMigrateVersion3 counterpart, we don't need
@@ -5573,7 +5608,9 @@ qemuMigrationSrcPerformPeer2Peer3(virQEMUDriver *driver,
} else {
dom_xml = qemuMigrationSrcBeginPhase(driver, vm, xmlin, dname,
&cookieout, &cookieoutlen,
- migrate_disks, flags);
+ migrate_disks,
+ migrate_disks_detect_zeroes,
+ flags);
}
if (!dom_xml)
goto cleanup;
@@ -5618,6 +5655,15 @@ qemuMigrationSrcPerformPeer2Peer3(virQEMUDriver *driver,
*d) < 0)
goto cleanup;
}
+ if (migrate_disks_detect_zeroes) {
+ const char **d;
+
+ for (d = migrate_disks_detect_zeroes; *d; d++)
+ if (virTypedParamsAddString(¶ms, &nparams, &maxparams,
+ VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES,
+ *d) < 0)
+ goto cleanup;
+ }
if (nbdPort &&
virTypedParamsAddInt(¶ms, &nparams, &maxparams,
VIR_MIGRATE_PARAM_DISKS_PORT,
@@ -5731,7 +5777,7 @@ qemuMigrationSrcPerformPeer2Peer3(virQEMUDriver *driver,
cookiein, cookieinlen,
&cookieout, &cookieoutlen,
flags, bandwidth, dconn, graphicsuri,
- migrate_disks,
+ migrate_disks, migrate_disks_detect_zeroes,
migParams, nbdURI);
}
@@ -5905,6 +5951,7 @@ qemuMigrationSrcPerformPeer2Peer(virQEMUDriver *driver,
const char *graphicsuri,
const char *listenAddress,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
int nbdPort,
const char *nbdURI,
qemuMigrationParams *migParams,
@@ -6029,7 +6076,7 @@ qemuMigrationSrcPerformPeer2Peer(virQEMUDriver *driver,
if (*v3proto) {
ret = qemuMigrationSrcPerformPeer2Peer3(driver, sconn, dconn, dconnuri, vm, xmlin,
persist_xml, dname, uri, graphicsuri,
- listenAddress, migrate_disks,
+ listenAddress, migrate_disks, migrate_disks_detect_zeroes,
nbdPort, nbdURI, migParams, resource,
!!useParams, flags);
} else {
@@ -6066,6 +6113,7 @@ qemuMigrationSrcPerformJob(virQEMUDriver *driver,
const char *graphicsuri,
const char *listenAddress,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
int nbdPort,
const char *nbdURI,
qemuMigrationParams *migParams,
@@ -6116,7 +6164,7 @@ qemuMigrationSrcPerformJob(virQEMUDriver *driver,
if ((flags & (VIR_MIGRATE_TUNNELLED | VIR_MIGRATE_PEER2PEER))) {
ret = qemuMigrationSrcPerformPeer2Peer(driver, conn, vm, xmlin, persist_xml,
dconnuri, uri, graphicsuri, listenAddress,
- migrate_disks, nbdPort,
+ migrate_disks, migrate_disks_detect_zeroes, nbdPort,
nbdURI,
migParams, flags, dname, resource,
&v3proto);
@@ -6126,7 +6174,7 @@ qemuMigrationSrcPerformJob(virQEMUDriver *driver,
ret = qemuMigrationSrcPerformNative(driver, vm, xmlin, persist_xml, uri, cookiein, cookieinlen,
cookieout, cookieoutlen,
- flags, resource, NULL, NULL, NULL,
+ flags, resource, NULL, NULL, NULL, NULL,
migParams, nbdURI);
}
if (ret < 0)
@@ -6194,6 +6242,7 @@ qemuMigrationSrcPerformPhase(virQEMUDriver *driver,
const char *uri,
const char *graphicsuri,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
qemuMigrationParams *migParams,
const char *cookiein,
int cookieinlen,
@@ -6229,7 +6278,8 @@ qemuMigrationSrcPerformPhase(virQEMUDriver *driver,
if (qemuMigrationSrcPerformNative(driver, vm, xmlin, persist_xml, uri, cookiein, cookieinlen,
cookieout, cookieoutlen,
flags, resource, NULL, graphicsuri,
- migrate_disks, migParams, nbdURI) < 0)
+ migrate_disks, migrate_disks_detect_zeroes,
+ migParams, nbdURI) < 0)
goto cleanup;
virCloseCallbacksDomainAdd(vm, conn, qemuMigrationAnyConnectionClosed);
@@ -6271,6 +6321,7 @@ qemuMigrationSrcPerform(virQEMUDriver *driver,
const char *graphicsuri,
const char *listenAddress,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
int nbdPort,
const char *nbdURI,
qemuMigrationParams *migParams,
@@ -6314,7 +6365,7 @@ qemuMigrationSrcPerform(virQEMUDriver *driver,
return qemuMigrationSrcPerformJob(driver, conn, vm, xmlin, persist_xml, dconnuri, uri,
graphicsuri, listenAddress,
- migrate_disks, nbdPort,
+ migrate_disks, migrate_disks_detect_zeroes, nbdPort,
nbdURI, migParams,
cookiein, cookieinlen,
cookieout, cookieoutlen,
@@ -6330,7 +6381,7 @@ qemuMigrationSrcPerform(virQEMUDriver *driver,
if (v3proto) {
return qemuMigrationSrcPerformPhase(driver, conn, vm, xmlin, persist_xml, uri,
graphicsuri,
- migrate_disks,
+ migrate_disks, migrate_disks_detect_zeroes,
migParams,
cookiein, cookieinlen,
cookieout, cookieoutlen,
@@ -6339,7 +6390,7 @@ qemuMigrationSrcPerform(virQEMUDriver *driver,
return qemuMigrationSrcPerformJob(driver, conn, vm, xmlin, persist_xml, NULL,
uri, graphicsuri, listenAddress,
- migrate_disks, nbdPort,
+ migrate_disks, migrate_disks_detect_zeroes, nbdPort,
nbdURI, migParams,
cookiein, cookieinlen,
cookieout, cookieoutlen, flags,
diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h
index 4dced4b166..4b7ef9688a 100644
--- a/src/qemu/qemu_migration.h
+++ b/src/qemu/qemu_migration.h
@@ -74,6 +74,8 @@
VIR_MIGRATE_PARAM_LISTEN_ADDRESS, VIR_TYPED_PARAM_STRING, \
VIR_MIGRATE_PARAM_MIGRATE_DISKS, VIR_TYPED_PARAM_STRING | \
VIR_TYPED_PARAM_MULTIPLE, \
+ VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES, VIR_TYPED_PARAM_STRING | \
+ VIR_TYPED_PARAM_MULTIPLE, \
VIR_MIGRATE_PARAM_DISKS_PORT, VIR_TYPED_PARAM_INT, \
VIR_MIGRATE_PARAM_COMPRESSION, VIR_TYPED_PARAM_STRING | \
VIR_TYPED_PARAM_MULTIPLE, \
@@ -123,6 +125,7 @@ qemuMigrationSrcBegin(virConnectPtr conn,
char **cookieout,
int *cookieoutlen,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
unsigned int flags);
virDomainDef *
@@ -174,6 +177,7 @@ qemuMigrationSrcPerform(virQEMUDriver *driver,
const char *graphicsuri,
const char *listenAddress,
const char **migrate_disks,
+ const char **migrate_disks_detect_zeroes,
int nbdPort,
const char *nbdURI,
qemuMigrationParams *migParams,
--
2.46.0On Mon, Sep 30, 2024 at 03:29:34PM +0200, Peter Krempa wrote:
> The new 'VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES' migration
> parameter allows users of migration to pass in a list of disks where
> zero-detection (which avoids transferring the zeroed-blocks) should be
> enabled for the migration connection. This comes at the cost of extra
> CPU cycles needed to check each block if it's all-zero.
>
> This is useful for storage backends where information about the
> allocation state of a block is not available and thus without this the
> image would become fully allocated on the destination.
>
> Signed-off-by: Peter Krempa <pkrempa@redhat.com>
> ---
> include/libvirt/libvirt-domain.h | 13 ++++
> src/qemu/qemu_driver.c | 20 ++++--
> src/qemu/qemu_migration.c | 105 +++++++++++++++++++++++--------
> src/qemu/qemu_migration.h | 4 ++
> 4 files changed, 110 insertions(+), 32 deletions(-)
>
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index 4266237abe..6d4cc69c5d 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -1240,6 +1240,19 @@ typedef enum {
> */
> # define VIR_MIGRATE_PARAM_MIGRATE_DISKS "migrate_disks"
>
> +/**
> + * VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES:
> + *
> + * virDomainMigrate* params multiple field: The multiple values that list
> + * the block devices for which zero detection (to avoid transferring zero blocks)
> + * is to be enabled. This may increase CPU overhead of the migration. At the
> + * moment this is only supported by the QEMU driver but not for the tunnelled
> + * migration.
We should note that it has to be subset of migrate_disks values. I also
wonder if we should add a code that will error out if it's not the case,
currently it would be silently ignored.
> + *
> + * Since: 10.9.0
> + */
> +# define VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES "migrate_disks_detect_zeroes"
> +
> /**
> * VIR_MIGRATE_PARAM_DISKS_PORT:
> *
[...]
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index 94636e778d..7ae19dd0ce 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -5316,9 +5348,11 @@ qemuMigrationSrcPerformTunnel(virQEMUDriver *driver,
> goto cleanup;
> }
>
> + /* Migration with NBD is not supported with _TUNNELED, thus
s/_TUNNELED/_TUNNELLED/
To match the incorrect spelling of the actual flag.
> + * 'migrate_disks_detect_zeroes' is NULL here */
> ret = qemuMigrationSrcRun(driver, vm, xmlin, persist_xml, cookiein, cookieinlen,
> cookieout, cookieoutlen, flags, resource, &spec,
> - dconn, graphicsuri, migrate_disks,
> + dconn, graphicsuri, migrate_disks, NULL,
> migParams, NULL);
>
> cleanup:
Pavel
On Mon, Sep 30, 2024 at 16:53:55 +0200, Pavel Hrdina wrote:
> On Mon, Sep 30, 2024 at 03:29:34PM +0200, Peter Krempa wrote:
> > The new 'VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES' migration
> > parameter allows users of migration to pass in a list of disks where
> > zero-detection (which avoids transferring the zeroed-blocks) should be
> > enabled for the migration connection. This comes at the cost of extra
> > CPU cycles needed to check each block if it's all-zero.
> >
> > This is useful for storage backends where information about the
> > allocation state of a block is not available and thus without this the
> > image would become fully allocated on the destination.
> >
> > Signed-off-by: Peter Krempa <pkrempa@redhat.com>
> > ---
> > include/libvirt/libvirt-domain.h | 13 ++++
> > src/qemu/qemu_driver.c | 20 ++++--
> > src/qemu/qemu_migration.c | 105 +++++++++++++++++++++++--------
> > src/qemu/qemu_migration.h | 4 ++
> > 4 files changed, 110 insertions(+), 32 deletions(-)
> >
> > diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> > index 4266237abe..6d4cc69c5d 100644
> > --- a/include/libvirt/libvirt-domain.h
> > +++ b/include/libvirt/libvirt-domain.h
> > @@ -1240,6 +1240,19 @@ typedef enum {
> > */
> > # define VIR_MIGRATE_PARAM_MIGRATE_DISKS "migrate_disks"
> >
> > +/**
> > + * VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES:
> > + *
> > + * virDomainMigrate* params multiple field: The multiple values that list
> > + * the block devices for which zero detection (to avoid transferring zero blocks)
> > + * is to be enabled. This may increase CPU overhead of the migration. At the
> > + * moment this is only supported by the QEMU driver but not for the tunnelled
> > + * migration.
>
> We should note that it has to be subset of migrate_disks values.
I'd argue that it's logical that this can apply only if the disk is
being migrated.
>I also
> wonder if we should add a code that will error out if it's not the case,
> currently it would be silently ignored.
I'm firmly in the 'no' region. This can be used also if 'migrate_disks'
is not used so we'd have to cross check against the logic if a disk is
even being migrated.
As written above I'm okay declaring that we "did in fact enable
zero-detection for given migration" if the disk was not
migrated as all zeroes were properly 100% absolutely surely always
detected during that migration. Yes I'm being sarcastic. No I'll not add
this pointless checking code. I was borderline thinking not adding the
check whether the disk targets are valid, but that could be easily
extracted&reused.
On Mon, Sep 30, 2024 at 06:34:05PM +0200, Peter Krempa wrote:
> On Mon, Sep 30, 2024 at 16:53:55 +0200, Pavel Hrdina wrote:
> > On Mon, Sep 30, 2024 at 03:29:34PM +0200, Peter Krempa wrote:
> > > The new 'VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES' migration
> > > parameter allows users of migration to pass in a list of disks where
> > > zero-detection (which avoids transferring the zeroed-blocks) should be
> > > enabled for the migration connection. This comes at the cost of extra
> > > CPU cycles needed to check each block if it's all-zero.
> > >
> > > This is useful for storage backends where information about the
> > > allocation state of a block is not available and thus without this the
> > > image would become fully allocated on the destination.
> > >
> > > Signed-off-by: Peter Krempa <pkrempa@redhat.com>
> > > ---
> > > include/libvirt/libvirt-domain.h | 13 ++++
> > > src/qemu/qemu_driver.c | 20 ++++--
> > > src/qemu/qemu_migration.c | 105 +++++++++++++++++++++++--------
> > > src/qemu/qemu_migration.h | 4 ++
> > > 4 files changed, 110 insertions(+), 32 deletions(-)
> > >
> > > diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> > > index 4266237abe..6d4cc69c5d 100644
> > > --- a/include/libvirt/libvirt-domain.h
> > > +++ b/include/libvirt/libvirt-domain.h
> > > @@ -1240,6 +1240,19 @@ typedef enum {
> > > */
> > > # define VIR_MIGRATE_PARAM_MIGRATE_DISKS "migrate_disks"
> > >
> > > +/**
> > > + * VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES:
> > > + *
> > > + * virDomainMigrate* params multiple field: The multiple values that list
> > > + * the block devices for which zero detection (to avoid transferring zero blocks)
> > > + * is to be enabled. This may increase CPU overhead of the migration. At the
> > > + * moment this is only supported by the QEMU driver but not for the tunnelled
> > > + * migration.
> >
> > We should note that it has to be subset of migrate_disks values.
>
> I'd argue that it's logical that this can apply only if the disk is
> being migrated.
My assumption was that it would apply only to disks listed in
VIR_MIGRATE_PARAM_MIGRATE_DISKS but due to incorrectly reading how
qemuMigrationAnyCopyDisk works it's not true so that comment would be
false as well.
With the _TUNNELLED fixed
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
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