From a1853831de58b56278ef02964fd8c86ed19c2007 Mon Sep 17 00:00:00 2001
From: Leonardo Bras <leobras@redhat.com>
Date: Mon, 20 Jun 2022 02:39:45 -0300
Subject: [PATCH 26/34] migration: Change zero_copy_send from migration
parameter to migration capability
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Leonardo Brás <leobras@redhat.com>
RH-MergeRequest: 185: MSG_ZEROCOPY + Multifd @ rhel8.6
RH-Commit: [26/34] 249c0aaac45b33db0ba2f6d2010d61947d4e96f9
RH-Bugzilla: 2117252
RH-Acked-by: quintela1 <quintela@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Peter Xu <peterx@redhat.com>
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
(cherry picked from commit 1abaec9a1b2c23f7aa94709a422128d9e42c3e0b)
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
migration/migration.c | 58 +++++++++++++++++++------------------------
monitor/hmp-cmds.c | 6 -----
qapi/migration.json | 33 +++++++-----------------
3 files changed, 34 insertions(+), 63 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index 5357efd348..c8aa55d2fe 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -162,7 +162,8 @@ 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);
bool migrate_pre_2_2;
@@ -888,10 +889,6 @@ 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;
@@ -1249,6 +1246,24 @@ 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_multifd_is_allowed() &&
@@ -1471,16 +1486,6 @@ 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;
}
@@ -1554,11 +1559,6 @@ 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;
}
@@ -1671,11 +1671,6 @@ 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);
@@ -2573,7 +2568,7 @@ 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
@@ -4236,10 +4231,6 @@ 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),
@@ -4277,6 +4268,10 @@ 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(),
};
@@ -4337,9 +4332,6 @@ 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;
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index e02da5008b..2669156b28 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1297,12 +1297,6 @@ 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)) {
diff --git a/qapi/migration.json b/qapi/migration.json
index 59b5c5780b..fe70a0c4b2 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -452,6 +452,13 @@
# 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.
#
@@ -465,7 +472,8 @@
'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:
@@ -730,12 +738,6 @@
# 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
@@ -776,7 +778,6 @@
'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' ] }
##
@@ -903,13 +904,6 @@
# 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
@@ -964,7 +958,6 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
- '*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##
@@ -1111,13 +1104,6 @@
# 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
@@ -1170,7 +1156,6 @@
'*multifd-compression': 'MultiFDCompression',
'*multifd-zlib-level': 'uint8',
'*multifd-zstd-level': 'uint8',
- '*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
'*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
##
--
2.35.3