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migration: Change zero_copy_send from migration parameter to migration capability

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When originally implemented, zero_copy_send was designed as a Migration
paramenter.

But taking into account how is that supposed to work, and how
the difference between a capability and a parameter, it only makes sense
that zero-copy-send would work better as a capability.

Taking into account how recently the change got merged, it was decided
that it's still time to make it right, and convert zero_copy_send into
a Migration capability.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: always define the capability, even on non-Linux but error if
set; avoids build problems with the capability
This commit is contained in:
Leonardo Bras 2022-06-20 02:39:45 -03:00 committed by Dr. David Alan Gilbert
parent 4f5a09714c
commit 1abaec9a1b
3 changed files with 34 additions and 63 deletions
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58
migration/migration.c
View File

@ -163,7 +163,8 @@ INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
MIGRATION_CAPABILITY_COMPRESS,
MIGRATION_CAPABILITY_XBZRLE,
MIGRATION_CAPABILITY_X_COLO,
MIGRATION_CAPABILITY_VALIDATE_UUID);
MIGRATION_CAPABILITY_VALIDATE_UUID,
MIGRATION_CAPABILITY_ZERO_COPY_SEND);
/* When we add fault tolerance, we could have several
migrations at once. For now we don't need to add
@ -910,10 +911,6 @@ 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;
@ -1275,6 +1272,24 @@ static bool migrate_caps_check(bool *cap_list,
}
}
#ifdef CONFIG_LINUX
if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND] &&
(!cap_list[MIGRATION_CAPABILITY_MULTIFD] ||
migrate_use_compression() ||
migrate_use_tls())) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS multifd migration");
return false;
}
#else
if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND]) {
error_setg(errp,
"Zero copy currently only available on Linux");
return false;
}
#endif
/* incoming side only */
if (runstate_check(RUN_STATE_INMIGRATE) &&
!migrate_multi_channels_is_allowed() &&
@ -1497,16 +1512,6 @@ static bool migrate_params_check(MigrationParameters *params, Error **errp)
error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: ");
return false;
}
#ifdef CONFIG_LINUX
if (params->zero_copy_send &&
(!migrate_use_multifd() ||
params->multifd_compression != MULTIFD_COMPRESSION_NONE ||
(params->tls_creds && *params->tls_creds))) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS multifd migration");
return false;
}
#endif
return true;
}
@ -1580,11 +1585,6 @@ 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;
}
@ -1697,11 +1697,6 @@ 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);
@ -2593,7 +2588,7 @@ bool migrate_use_zero_copy_send(void)
s = migrate_get_current();
return s->parameters.zero_copy_send;
return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_COPY_SEND];
}
#endif
@ -4249,10 +4244,6 @@ 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),
@ -4290,6 +4281,10 @@ static Property migration_properties[] = {
DEFINE_PROP_MIG_CAP("x-multifd", MIGRATION_CAPABILITY_MULTIFD),
DEFINE_PROP_MIG_CAP("x-background-snapshot",
MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT),
#ifdef CONFIG_LINUX
DEFINE_PROP_MIG_CAP("x-zero-copy-send",
MIGRATION_CAPABILITY_ZERO_COPY_SEND),
#endif
DEFINE_PROP_END_OF_LIST(),
};
@ -4350,9 +4345,6 @@ 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;

6
monitor/hmp-cmds.c
View File

@ -1311,12 +1311,6 @@ 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)) {

33
qapi/migration.json
View File

@ -461,6 +461,13 @@
# procedure starts. The VM RAM is saved with running VM.
# (since 6.0)
#
# @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.
# (since 7.1)
#
# Features:
# @unstable: Members @x-colo and @x-ignore-shared are experimental.
#
@ -474,7 +481,8 @@
'block', 'return-path', 'pause-before-switchover', 'multifd',
'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
{ 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
'validate-uuid', 'background-snapshot'] }
'validate-uuid', 'background-snapshot',
'zero-copy-send'] }
##
# @MigrationCapabilityStatus:
@ -738,12 +746,6 @@
# 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
@ -784,7 +786,6 @@
'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' ] }
##
@ -911,13 +912,6 @@
# 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
@ -972,7 +966,6 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
'*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##
@ -1119,13 +1112,6 @@
# 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
@ -1178,7 +1164,6 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
'*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##