From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Introduce "vcpu-dirty-limit" migration parameter used
to limit dirty page rate during live migration.
"vcpu-dirty-limit" and "x-vcpu-dirty-limit-period" are
two dirty-limit-related migration parameters, which can
be set before and during live migration by qmp
migrate-set-parameters.
This two parameters are used to help implement the dirty
page rate limit algo of migration.
Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
---
migration/migration.c | 14 ++++++++++++++
monitor/hmp-cmds.c | 8 ++++++++
qapi/migration.json | 18 +++++++++++++++---
3 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index 7b19f85..ed1a47b 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -117,6 +117,7 @@
#define DEFAULT_MIGRATE_ANNOUNCE_STEP 100
#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD 500 /* ms */
+#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT 1 /* MB/s */
static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
@@ -967,6 +968,9 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
params->has_x_vcpu_dirty_limit_period = true;
params->x_vcpu_dirty_limit_period = s->parameters.x_vcpu_dirty_limit_period;
+ params->has_vcpu_dirty_limit = true;
+ params->vcpu_dirty_limit = s->parameters.vcpu_dirty_limit;
+
return params;
}
@@ -1671,6 +1675,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
if (params->has_x_vcpu_dirty_limit_period) {
dest->x_vcpu_dirty_limit_period = params->x_vcpu_dirty_limit_period;
}
+
+ if (params->has_vcpu_dirty_limit) {
+ dest->vcpu_dirty_limit = params->vcpu_dirty_limit;
+ }
}
static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
@@ -1797,6 +1805,9 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
s->parameters.x_vcpu_dirty_limit_period =
params->x_vcpu_dirty_limit_period;
}
+ if (params->has_vcpu_dirty_limit) {
+ s->parameters.vcpu_dirty_limit = params->vcpu_dirty_limit;
+ }
}
void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
@@ -4400,6 +4411,9 @@ static Property migration_properties[] = {
DEFINE_PROP_UINT64("x-vcpu-dirty-limit-period", MigrationState,
parameters.x_vcpu_dirty_limit_period,
DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD),
+ DEFINE_PROP_UINT64("vcpu-dirty-limit", MigrationState,
+ parameters.vcpu_dirty_limit,
+ DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT),
/* Migration capabilities */
DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 64c996c..acbc5e8 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -536,6 +536,10 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
monitor_printf(mon, "%s: %" PRIu64 " ms\n",
MigrationParameter_str(MIGRATION_PARAMETER_X_VCPU_DIRTY_LIMIT_PERIOD),
params->x_vcpu_dirty_limit_period);
+
+ monitor_printf(mon, "%s: %" PRIu64 " MB/s\n",
+ MigrationParameter_str(MIGRATION_PARAMETER_VCPU_DIRTY_LIMIT),
+ params->vcpu_dirty_limit);
}
qapi_free_MigrationParameters(params);
@@ -1359,6 +1363,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
p->has_x_vcpu_dirty_limit_period = true;
visit_type_size(v, param, &p->x_vcpu_dirty_limit_period, &err);
break;
+ case MIGRATION_PARAMETER_VCPU_DIRTY_LIMIT:
+ p->has_vcpu_dirty_limit = true;
+ visit_type_size(v, param, &p->vcpu_dirty_limit, &err);
+ break;
default:
assert(0);
}
diff --git a/qapi/migration.json b/qapi/migration.json
index 332c087..0963bab 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -779,6 +779,9 @@
# @x-vcpu-dirty-limit-period: Periodic time (ms) of dirty limit during live migration.
# Defaults to 500ms. (Since 7.1)
#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+# Defaults to 1. (Since 7.1)
+#
# Features:
# @unstable: Member @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -801,7 +804,8 @@
'max-cpu-throttle', 'multifd-compression',
'multifd-zlib-level', 'multifd-zstd-level',
'block-bitmap-mapping',
- { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] } ] }
+ { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] },
+ 'vcpu-dirty-limit'] }
##
# @MigrateSetParameters:
@@ -949,6 +953,9 @@
# @x-vcpu-dirty-limit-period: Periodic time (ms) of dirty limit during live migration.
# Defaults to 500ms. (Since 7.1)
#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+# Defaults to 1. (Since 7.1)
+#
# Features:
# @unstable: Member @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -987,7 +994,8 @@
'*multifd-zstd-level': 'uint8',
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
'*x-vcpu-dirty-limit-period': { 'type': 'uint64',
- 'features': [ 'unstable' ] } } }
+ 'features': [ 'unstable' ] },
+ '*vcpu-dirty-limit': 'uint64'} }
##
# @migrate-set-parameters:
@@ -1155,6 +1163,9 @@
# @x-vcpu-dirty-limit-period: Periodic time (ms) of dirty limit during live migration.
# Defaults to 500ms. (Since 7.1)
#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+# Defaults to 1. (Since 7.1)
+#
# Features:
# @unstable: Member @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -1191,7 +1202,8 @@
'*multifd-zstd-level': 'uint8',
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
'*x-vcpu-dirty-limit-period': { 'type': 'uint64',
- 'features': [ 'unstable' ] } } }
+ 'features': [ 'unstable' ] },
+ '*vcpu-dirty-limit': 'uint64'} }
##
# @query-migrate-parameters:
--
1.8.3.1
On Sat, Jul 23, 2022 at 03:49:14PM +0800, huangy81@chinatelecom.cn wrote: > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > Introduce "vcpu-dirty-limit" migration parameter used > to limit dirty page rate during live migration. > > "vcpu-dirty-limit" and "x-vcpu-dirty-limit-period" are > two dirty-limit-related migration parameters, which can > be set before and during live migration by qmp > migrate-set-parameters. > > This two parameters are used to help implement the dirty > page rate limit algo of migration. > > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > --- > migration/migration.c | 14 ++++++++++++++ > monitor/hmp-cmds.c | 8 ++++++++ > qapi/migration.json | 18 +++++++++++++++--- > 3 files changed, 37 insertions(+), 3 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 7b19f85..ed1a47b 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -117,6 +117,7 @@ > #define DEFAULT_MIGRATE_ANNOUNCE_STEP 100 > > #define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD 500 /* ms */ > +#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT 1 /* MB/s */ This default value also looks a bit weird.. why 1MB/s? Thanks, -- Peter Xu
在 2022/8/18 6:07, Peter Xu 写道: > On Sat, Jul 23, 2022 at 03:49:14PM +0800, huangy81@chinatelecom.cn wrote: >> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> >> Introduce "vcpu-dirty-limit" migration parameter used >> to limit dirty page rate during live migration. >> >> "vcpu-dirty-limit" and "x-vcpu-dirty-limit-period" are >> two dirty-limit-related migration parameters, which can >> be set before and during live migration by qmp >> migrate-set-parameters. >> >> This two parameters are used to help implement the dirty >> page rate limit algo of migration. >> >> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> --- >> migration/migration.c | 14 ++++++++++++++ >> monitor/hmp-cmds.c | 8 ++++++++ >> qapi/migration.json | 18 +++++++++++++++--- >> 3 files changed, 37 insertions(+), 3 deletions(-) >> >> diff --git a/migration/migration.c b/migration/migration.c >> index 7b19f85..ed1a47b 100644 >> --- a/migration/migration.c >> +++ b/migration/migration.c >> @@ -117,6 +117,7 @@ >> #define DEFAULT_MIGRATE_ANNOUNCE_STEP 100 >> >> #define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD 500 /* ms */ >> +#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT 1 /* MB/s */ > > This default value also looks a bit weird.. why 1MB/s? Thanks, Indeed, it seems kind of weired, the reason to set default dirty limit to 1MB/s is that we want to keep the dirty limit working until vcpu dirty page rate drop to 1MB/s once dirtylimit capability enabled during migration. In this way, migration has the largest chance to get converged before vcpu dirty page rate drop to 1MB/s。 If we set default dirty limit greater than 1MB/s, the probability of success for migration may be reduced, and the default behavior of migration is try the best to become sucessful. >
© 2016 - 2026 Red Hat, Inc.