[PATCH v4 06/10] migration: Deprecate old compression method
Juan Quintela
quintela at redhat.com
Fri Oct 13 10:47:32 UTC 2023
Signed-off-by: Juan Quintela <quintela at redhat.com>
Acked-by: Stefan Hajnoczi <stefanha at redhat.com>
Acked-by: Peter Xu <peterx at redhat.com>
---
docs/about/deprecated.rst | 8 ++++
qapi/migration.json | 79 +++++++++++++++++++++++++--------------
migration/options.c | 13 +++++++
3 files changed, 72 insertions(+), 28 deletions(-)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 6490925cdc..a6da0df8e1 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -476,3 +476,11 @@ Please see "QMP invocation for live storage migration with
``blockdev-mirror`` + NBD" in docs/interop/live-block-operations.rst
for a detailed explanation.
+old compression method (since 8.2)
+''''''''''''''''''''''''''''''''''
+
+Compression method fails too much. Too many races. We are going to
+remove it if nobody fixes it. For starters, migration-test
+compression tests are disabled becase they fail randomly. If you need
+compression, use multifd compression methods.
+
diff --git a/qapi/migration.json b/qapi/migration.json
index 5e545d10c0..e599062f7d 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -272,6 +272,10 @@
# Features:
#
# @deprecated: Member @disk is deprecated because block migration is.
+# Member @compression is deprecated because it is unreliable and
+# untested. It is recommended to use multifd migration, which
+# offers an alternative compression implementation that is
+# reliable and tested.
#
# Since: 0.14
##
@@ -289,7 +293,7 @@
'*blocked-reasons': ['str'],
'*postcopy-blocktime': 'uint32',
'*postcopy-vcpu-blocktime': ['uint32'],
- '*compression': 'CompressionStats',
+ '*compression': { 'type': 'CompressionStats', 'features': [ 'deprecated' ] },
'*socket-address': ['SocketAddress'],
'*dirty-limit-throttle-time-per-round': 'uint64',
'*dirty-limit-ring-full-time': 'uint64'} }
@@ -530,7 +534,10 @@
# Features:
#
# @deprecated: Member @block is deprecated. Use blockdev-mirror with
-# NBD instead.
+# NBD instead. Member @compression is deprecated because it is
+# unreliable and untested. It is recommended to use multifd
+# migration, which offers an alternative compression
+# implementation that is reliable and tested.
#
# @unstable: Members @x-colo and @x-ignore-shared are experimental.
#
@@ -538,7 +545,8 @@
##
{ 'enum': 'MigrationCapability',
'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
- 'compress', 'events', 'postcopy-ram',
+ { 'name': 'compress', 'features': [ 'deprecated' ] },
+ 'events', 'postcopy-ram',
{ 'name': 'x-colo', 'features': [ 'unstable' ] },
'release-ram',
{ 'name': 'block', 'features': [ 'deprecated' ] },
@@ -834,7 +842,9 @@
# Features:
#
# @deprecated: Member @block-incremental is deprecated. Use
-# blockdev-mirror with NBD instead.
+# blockdev-mirror with NBD instead. Members @compress-level,
+# @compress-threads, @decompress-threads and @compress-wait-thread
+# are deprecated because @compression is deprecated.
#
# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -844,8 +854,11 @@
{ 'enum': 'MigrationParameter',
'data': ['announce-initial', 'announce-max',
'announce-rounds', 'announce-step',
- 'compress-level', 'compress-threads', 'decompress-threads',
- 'compress-wait-thread', 'throttle-trigger-threshold',
+ { 'name': 'compress-level', 'features': [ 'deprecated' ] },
+ { 'name': 'compress-threads', 'features': [ 'deprecated' ] },
+ { 'name': 'decompress-threads', 'features': [ 'deprecated' ] },
+ { 'name': 'compress-wait-thread', 'features': [ 'deprecated' ] },
+ 'throttle-trigger-threshold',
'cpu-throttle-initial', 'cpu-throttle-increment',
'cpu-throttle-tailslow',
'tls-creds', 'tls-hostname', 'tls-authz', 'max-bandwidth',
@@ -875,16 +888,16 @@
# @announce-step: Increase in delay (in milliseconds) between
# subsequent packets in the announcement (Since 4.0)
#
-# @compress-level: compression level
+# @compress-level: compression level.
#
-# @compress-threads: compression thread count
+# @compress-threads: compression thread count.
#
# @compress-wait-thread: Controls behavior when all compression
# threads are currently busy. If true (default), wait for a free
# compression thread to become available; otherwise, send the page
-# uncompressed. (Since 3.1)
+# uncompressed. (Since 3.1)
#
-# @decompress-threads: decompression thread count
+# @decompress-threads: decompression thread count.
#
# @throttle-trigger-threshold: The ratio of bytes_dirty_period and
# bytes_xfer_period to trigger throttling. It is expressed as
@@ -1003,7 +1016,9 @@
# Features:
#
# @deprecated: Member @block-incremental is deprecated. Use
-# blockdev-mirror with NBD instead.
+# blockdev-mirror with NBD instead. Members @compress-level,
+# @compress-threads, @decompress-threads and @compress-wait-thread
+# are deprecated because @compression is deprecated.
#
# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -1018,10 +1033,14 @@
'*announce-max': 'size',
'*announce-rounds': 'size',
'*announce-step': 'size',
- '*compress-level': 'uint8',
- '*compress-threads': 'uint8',
- '*compress-wait-thread': 'bool',
- '*decompress-threads': 'uint8',
+ '*compress-level': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
+ '*compress-threads': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
+ '*compress-wait-thread': { 'type': 'bool',
+ 'features': [ 'deprecated' ] },
+ '*decompress-threads': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
'*throttle-trigger-threshold': 'uint8',
'*cpu-throttle-initial': 'uint8',
'*cpu-throttle-increment': 'uint8',
@@ -1057,7 +1076,7 @@
# Example:
#
# -> { "execute": "migrate-set-parameters" ,
-# "arguments": { "compress-level": 1 } }
+# "arguments": { "multifd-channels": 5 } }
# <- { "return": {} }
##
{ 'command': 'migrate-set-parameters', 'boxed': true,
@@ -1080,16 +1099,16 @@
# @announce-step: Increase in delay (in milliseconds) between
# subsequent packets in the announcement (Since 4.0)
#
-# @compress-level: compression level
+# @compress-level: compression level.
#
-# @compress-threads: compression thread count
+# @compress-threads: compression thread count.
#
# @compress-wait-thread: Controls behavior when all compression
# threads are currently busy. If true (default), wait for a free
# compression thread to become available; otherwise, send the page
-# uncompressed. (Since 3.1)
+# uncompressed. (Since 3.1)
#
-# @decompress-threads: decompression thread count
+# @decompress-threads: decompression thread count.
#
# @throttle-trigger-threshold: The ratio of bytes_dirty_period and
# bytes_xfer_period to trigger throttling. It is expressed as
@@ -1210,7 +1229,9 @@
# Features:
#
# @deprecated: Member @block-incremental is deprecated. Use
-# blockdev-mirror with NBD instead.
+# blockdev-mirror with NBD instead. Members @compress-level,
+# @compress-threads, @decompress-threads and @compress-wait-thread
+# are deprecated because @compression is deprecated.
#
# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
# are experimental.
@@ -1222,10 +1243,14 @@
'*announce-max': 'size',
'*announce-rounds': 'size',
'*announce-step': 'size',
- '*compress-level': 'uint8',
- '*compress-threads': 'uint8',
- '*compress-wait-thread': 'bool',
- '*decompress-threads': 'uint8',
+ '*compress-level': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
+ '*compress-threads': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
+ '*compress-wait-thread': { 'type': 'bool',
+ 'features': [ 'deprecated' ] },
+ '*decompress-threads': { 'type': 'uint8',
+ 'features': [ 'deprecated' ] },
'*throttle-trigger-threshold': 'uint8',
'*cpu-throttle-initial': 'uint8',
'*cpu-throttle-increment': 'uint8',
@@ -1264,10 +1289,8 @@
#
# -> { "execute": "query-migrate-parameters" }
# <- { "return": {
-# "decompress-threads": 2,
+# "multifd-channels": 2,
# "cpu-throttle-increment": 10,
-# "compress-threads": 8,
-# "compress-level": 1,
# "cpu-throttle-initial": 20,
# "max-bandwidth": 33554432,
# "downtime-limit": 300
diff --git a/migration/options.c b/migration/options.c
index bb6005052f..e46d847de2 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -474,6 +474,11 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
"Use blockdev-mirror with NBD instead.");
}
+ if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
+ warn_report("Old compression method is deprecated. "
+ "Use multifd compression methods instead.");
+ }
+
#ifndef CONFIG_REPLICATION
if (new_caps[MIGRATION_CAPABILITY_X_COLO]) {
error_setg(errp, "QEMU compiled without replication module"
@@ -1290,18 +1295,26 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
/* TODO use QAPI_CLONE() instead of duplicating it inline */
if (params->has_compress_level) {
+ warn_report("Old compression is deprecated. "
+ "Use multifd compression methods instead.");
s->parameters.compress_level = params->compress_level;
}
if (params->has_compress_threads) {
+ warn_report("Old compression is deprecated. "
+ "Use multifd compression methods instead.");
s->parameters.compress_threads = params->compress_threads;
}
if (params->has_compress_wait_thread) {
+ warn_report("Old compression is deprecated. "
+ "Use multifd compression methods instead.");
s->parameters.compress_wait_thread = params->compress_wait_thread;
}
if (params->has_decompress_threads) {
+ warn_report("Old compression is deprecated. "
+ "Use multifd compression methods instead.");
s->parameters.decompress_threads = params->decompress_threads;
}
--
2.41.0
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