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migration: Add zero-copy-send parameter for QMP/HMP for Linux 

Add property that allows zero-copy migration of memory pages
on the sending side, and also includes a helper function
migrate_use_zero_copy_send() to check if it's enabled.

No code is introduced to actually do the migration, but it allow
future implementations to enable/disable this feature.

On non-Linux builds this parameter is compiled-out.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220513062836.965425-5-leobras@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Leonardo Bras 2022-05-13 03:28:33 -03:00 committed by Dr. David Alan Gilbert
parent 2bc58ffc29
commit abb6295b3a
5 changed files with 76 additions and 2 deletions
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32
migration/migration.c
View File

@ -910,6 +910,10 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
params->multifd_zlib_level = s->parameters.multifd_zlib_level;
params->has_multifd_zstd_level = true;
params->multifd_zstd_level = s->parameters.multifd_zstd_level;
#ifdef CONFIG_LINUX
params->has_zero_copy_send = true;
params->zero_copy_send = s->parameters.zero_copy_send;
#endif
params->has_xbzrle_cache_size = true;
params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
params->has_max_postcopy_bandwidth = true;
@ -1567,6 +1571,11 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
if (params->has_multifd_compression) {
dest->multifd_compression = params->multifd_compression;
}
#ifdef CONFIG_LINUX
if (params->has_zero_copy_send) {
dest->zero_copy_send = params->zero_copy_send;
}
#endif
if (params->has_xbzrle_cache_size) {
dest->xbzrle_cache_size = params->xbzrle_cache_size;
}
@ -1679,6 +1688,11 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
if (params->has_multifd_compression) {
s->parameters.multifd_compression = params->multifd_compression;
}
#ifdef CONFIG_LINUX
if (params->has_zero_copy_send) {
s->parameters.zero_copy_send = params->zero_copy_send;
}
#endif
if (params->has_xbzrle_cache_size) {
s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
xbzrle_cache_resize(params->xbzrle_cache_size, errp);
@ -2563,6 +2577,17 @@ int migrate_multifd_zstd_level(void)
return s->parameters.multifd_zstd_level;
}
#ifdef CONFIG_LINUX
bool migrate_use_zero_copy_send(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.zero_copy_send;
}
#endif
int migrate_use_xbzrle(void)
{
MigrationState *s;
@ -4206,6 +4231,10 @@ static Property migration_properties[] = {
DEFINE_PROP_UINT8("multifd-zstd-level", MigrationState,
parameters.multifd_zstd_level,
DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL),
#ifdef CONFIG_LINUX
DEFINE_PROP_BOOL("zero_copy_send", MigrationState,
parameters.zero_copy_send, false),
#endif
DEFINE_PROP_SIZE("xbzrle-cache-size", MigrationState,
parameters.xbzrle_cache_size,
DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE),
@ -4303,6 +4332,9 @@ static void migration_instance_init(Object *obj)
params->has_multifd_compression = true;
params->has_multifd_zlib_level = true;
params->has_multifd_zstd_level = true;
#ifdef CONFIG_LINUX
params->has_zero_copy_send = true;
#endif
params->has_xbzrle_cache_size = true;
params->has_max_postcopy_bandwidth = true;
params->has_max_cpu_throttle = true;

5
migration/migration.h
View File

@ -375,6 +375,11 @@ MultiFDCompression migrate_multifd_compression(void);
int migrate_multifd_zlib_level(void);
int migrate_multifd_zstd_level(void);
#ifdef CONFIG_LINUX
bool migrate_use_zero_copy_send(void);
#else
#define migrate_use_zero_copy_send() (false)
#endif
int migrate_use_xbzrle(void);
uint64_t migrate_xbzrle_cache_size(void);
bool migrate_colo_enabled(void);

11
migration/socket.c
View File

@ -74,9 +74,16 @@ static void socket_outgoing_migration(QIOTask *task,
if (qio_task_propagate_error(task, &err)) {
trace_migration_socket_outgoing_error(error_get_pretty(err));
} else {
trace_migration_socket_outgoing_connected(data->hostname);
goto out;
}
trace_migration_socket_outgoing_connected(data->hostname);
if (migrate_use_zero_copy_send()) {
error_setg(&err, "Zero copy send not available in migration");
}
out:
migration_channel_connect(data->s, sioc, data->hostname, err);
object_unref(OBJECT(sioc));
}

6
monitor/hmp-cmds.c
View File

@ -1309,6 +1309,12 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
p->has_multifd_zstd_level = true;
visit_type_uint8(v, param, &p->multifd_zstd_level, &err);
break;
#ifdef CONFIG_LINUX
case MIGRATION_PARAMETER_ZERO_COPY_SEND:
p->has_zero_copy_send = true;
visit_type_bool(v, param, &p->zero_copy_send, &err);
break;
#endif
case MIGRATION_PARAMETER_XBZRLE_CACHE_SIZE:
p->has_xbzrle_cache_size = true;
if (!visit_type_size(v, param, &cache_size, &err)) {

24
qapi/migration.json
View File

@ -741,6 +741,13 @@
# will consume more CPU.
# Defaults to 1. (Since 5.0)
#
# @zero-copy-send: Controls behavior on sending memory pages on migration.
# When true, enables a zero-copy mechanism for sending
# memory pages, if host supports it.
# Requires that QEMU be permitted to use locked memory
# for guest RAM pages.
# Defaults to false. (Since 7.1)
#
# @block-bitmap-mapping: Maps block nodes and bitmaps on them to
# aliases for the purpose of dirty bitmap migration. Such
# aliases may for example be the corresponding names on the
@ -780,6 +787,7 @@
'xbzrle-cache-size', 'max-postcopy-bandwidth',
'max-cpu-throttle', 'multifd-compression',
'multifd-zlib-level' ,'multifd-zstd-level',
{ 'name': 'zero-copy-send', 'if' : 'CONFIG_LINUX'},
'block-bitmap-mapping' ] }
##
@ -906,6 +914,13 @@
# will consume more CPU.
# Defaults to 1. (Since 5.0)
#
# @zero-copy-send: Controls behavior on sending memory pages on migration.
# When true, enables a zero-copy mechanism for sending
# memory pages, if host supports it.
# Requires that QEMU be permitted to use locked memory
# for guest RAM pages.
# Defaults to false. (Since 7.1)
#
# @block-bitmap-mapping: Maps block nodes and bitmaps on them to
# aliases for the purpose of dirty bitmap migration. Such
# aliases may for example be the corresponding names on the
@ -960,6 +975,7 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
'*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##
@ -1106,6 +1122,13 @@
# will consume more CPU.
# Defaults to 1. (Since 5.0)
#
# @zero-copy-send: Controls behavior on sending memory pages on migration.
# When true, enables a zero-copy mechanism for sending
# memory pages, if host supports it.
# Requires that QEMU be permitted to use locked memory
# for guest RAM pages.
# Defaults to false. (Since 7.1)
#
# @block-bitmap-mapping: Maps block nodes and bitmaps on them to
# aliases for the purpose of dirty bitmap migration. Such
# aliases may for example be the corresponding names on the
@ -1158,6 +1181,7 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
'*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##