[PATCH v5 5/7] migration: Deprecate old compression method
Markus Armbruster
armbru at redhat.com
Tue Oct 17 14:03:03 UTC 2023
Juan Quintela <quintela at redhat.com> writes:
> 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 5eaf096040..f46baf9ee9 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -489,3 +489,11 @@ 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 c7633b22c0..834506a02b 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.
Two spaces between sentences for consistency, please.
> #
> # 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.
Likewise.
> #
> # @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' ] },
> @@ -844,7 +852,9 @@
> # 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.
Likewise.
> #
> # @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
> # are experimental.
> @@ -854,8 +864,11 @@
> { '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',
> @@ -885,16 +898,16 @@
> # @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
Unrelated.
> @@ -1023,7 +1036,9 @@
> # 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.
Two spaces between sentences for consistency, please.
> #
> # @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
> # are experimental.
> @@ -1038,10 +1053,14 @@
> '*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',
> @@ -1078,7 +1097,7 @@
> # Example:
> #
> # -> { "execute": "migrate-set-parameters" ,
> -# "arguments": { "compress-level": 1 } }
> +# "arguments": { "multifd-channels": 5 } }
> # <- { "return": {} }
> ##
Thanks for taking care of updating the example!
> { 'command': 'migrate-set-parameters', 'boxed': true,
> @@ -1101,16 +1120,16 @@
> # @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
Unrelated.
> @@ -1241,7 +1260,9 @@
> # 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.
Two spaces between sentences for consistency, please.
> #
> # @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
> # are experimental.
> @@ -1253,10 +1274,14 @@
> '*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',
> @@ -1296,10 +1321,8 @@
> #
> # -> { "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
Thanks again!
> diff --git a/migration/options.c b/migration/options.c
> index 0d0a3f8edb..7cb99a82a5 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -483,6 +483,11 @@ 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"
> @@ -1321,18 +1326,26 @@ 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;
> }
Other than that
Reviewed-by: Markus Armbruster <armbru at redhat.com>
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