[PATCH v4] numa: forbid '-numa node,mem' for 5.1 and newer machine types
Eric Blake
eblake at redhat.com
Mon Jun 8 15:53:27 UTC 2020
On 6/8/20 7:03 AM, Igor Mammedov wrote:
> Deprecation period is run out and it's a time to flip the switch
> introduced by cd5ff8333a. Disable legacy option for new machine
> types (since 5.1) and amend documentation.
>
> '-numa node,memdev' shall be used instead of disabled option
> with new machine types.
>
> Signed-off-by: Igor Mammedov <imammedo at redhat.com>
> Reviewed-by: Michal Privoznik <mprivozn at redhat.com>
> ---
> +++ b/docs/system/deprecated.rst
> @@ -101,23 +101,6 @@ error in the future.
> The ``-realtime mlock=on|off`` argument has been replaced by the
> ``-overcommit mem-lock=on|off`` argument.
>
> -``-numa node,mem=``\ *size* (since 4.1)
> -'''''''''''''''''''''''''''''''''''''''
> -
> -The parameter ``mem`` of ``-numa node`` is used to assign a part of
Present tense in the old text made sense because the old way still worked...
> -guest RAM to a NUMA node. But when using it, it's impossible to manage specified
> -RAM chunk on the host side (like bind it to a host node, setting bind policy, ...),
> -so guest end-ups with the fake NUMA configuration with suboptiomal performance.
> -However since 2014 there is an alternative way to assign RAM to a NUMA node
> -using parameter ``memdev``, which does the same as ``mem`` and adds
> -means to actualy manage node RAM on the host side. Use parameter ``memdev``
> -with *memory-backend-ram* backend as an replacement for parameter ``mem``
> -to achieve the same fake NUMA effect or a properly configured
> -*memory-backend-file* backend to actually benefit from NUMA configuration.
> -In future new machine versions will not accept the option but it will still
> -work with old machine types. User can check QAPI schema to see if the legacy
> -option is supported by looking at MachineInfo::numa-mem-supported property.
> -
> ``-numa`` node (without memory specified) (since 4.1)
> '''''''''''''''''''''''''''''''''''''''''''''''''''''
>
> @@ -516,3 +499,23 @@ long starting at 1MiB, the old command::
> can be rewritten as::
>
> qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2
> +
> +Command line options
> +--------------------
> +
> +``-numa node,mem=``\ *size* (removed in 5.1)
> +''''''''''''''''''''''''''''''''''''''''''''
> +
> +The parameter ``mem`` of ``-numa node`` is used to assign a part of
...but in the new text, if we completely got rid of 'mem', then past
tense is preferred to describe what used to work. s/is/was/
Other pre-existing typo and grammar problems worth fixing now:
> +guest RAM to a NUMA node. But when using it, it's impossible to manage specified
s/manage/manage a/
> +RAM chunk on the host side (like bind it to a host node, setting bind policy, ...),
> +so guest end-ups with the fake NUMA configuration with suboptiomal performance.
s/so guest end-ups/so the guest ends up/
> +However since 2014 there is an alternative way to assign RAM to a NUMA node
> +using parameter ``memdev``, which does the same as ``mem`` and adds
> +means to actualy manage node RAM on the host side. Use parameter ``memdev``
s/actualy/actually/
> +with *memory-backend-ram* backend as an replacement for parameter ``mem``
s/an/a/
> +to achieve the same fake NUMA effect or a properly configured
> +*memory-backend-file* backend to actually benefit from NUMA configuration.
> +In future new machine versions will not accept the option but it will still
If this sentence is still true:
s/In future new/New/
If the sentence is false (that is, we completely dropped 'mem' even for
old machine versions), drop it.
> +work with old machine types. User can check QAPI schema to see if the legacy
s/check/check the/
> +option is supported by looking at MachineInfo::numa-mem-supported property.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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