[PATCH v4] numa: forbid '-numa node,mem' for 5.1 and newer machine types

Michael S. Tsirkin mst at redhat.com
Mon Jun 8 12:55:08 UTC 2020


On Mon, Jun 08, 2020 at 08:03:44AM -0400, 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>

Reviewed-by: Michael S. Tsirkin <mst at redhat.com>


numa things so I'm guessing Eduardo's tree?

> ---
> v1:
>  - rebased on top of current master
>  - move compat mode from 4.2 to 5.0
> v2:
>  - move deprection text to recently removed section
> v3:
>  - increase title line length for (deprecated.rst)
>      '``-numa node,mem=``\ *size* (removed in 5.1)'
> v4:
>  - use error_append_hint() for suggesting valid CLI
> 
> CC: peter.maydell at linaro.org
> CC: ehabkost at redhat.com
> CC: marcel.apfelbaum at gmail.com
> CC: mst at redhat.com
> CC: pbonzini at redhat.com
> CC: rth at twiddle.net
> CC: david at gibson.dropbear.id.au
> CC: libvir-list at redhat.com
> CC: qemu-arm at nongnu.org
> CC: qemu-ppc at nongnu.org
> CC: eblake at redhat.com
> CC: groug at kaod.org
> ---
>  docs/system/deprecated.rst | 37 ++++++++++++++++++++-----------------
>  hw/arm/virt.c              |  2 +-
>  hw/core/numa.c             |  7 +++++++
>  hw/i386/pc.c               |  1 -
>  hw/i386/pc_piix.c          |  1 +
>  hw/i386/pc_q35.c           |  1 +
>  hw/ppc/spapr.c             |  2 +-
>  qemu-options.hx            |  9 +++++----
>  8 files changed, 36 insertions(+), 24 deletions(-)
> 
> diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
> index 544ece0a45..e74a5717c8 100644
> --- a/docs/system/deprecated.rst
> +++ 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  The ``-realtime mlock=on|off`` argument has been replaced by the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
> -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
> +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.
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 37462a6f78..063d4703f7 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2262,7 +2262,6 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
>      hc->pre_plug = virt_machine_device_pre_plug_cb;
>      hc->plug = virt_machine_device_plug_cb;
>      hc->unplug_request = virt_machine_device_unplug_request_cb;
> -    mc->numa_mem_supported = true;
>      mc->nvdimm_supported = true;
>      mc->auto_enable_numa_with_memhp = true;
>      mc->default_ram_id = "mach-virt.ram";
> @@ -2375,6 +2374,7 @@ DEFINE_VIRT_MACHINE_AS_LATEST(5, 1)
>  static void virt_machine_5_0_options(MachineClass *mc)
>  {
>      virt_machine_5_1_options(mc);
> +    mc->numa_mem_supported = true;
>  }
>  DEFINE_VIRT_MACHINE(5, 0)
>  
> diff --git a/hw/core/numa.c b/hw/core/numa.c
> index 316bc50d75..7814e646e4 100644
> --- a/hw/core/numa.c
> +++ b/hw/core/numa.c
> @@ -117,6 +117,13 @@ static void parse_numa_node(MachineState *ms, NumaNodeOptions *node,
>      }
>  
>      if (node->has_mem) {
> +        if (!mc->numa_mem_supported) {
> +            error_setg(errp, "Parameter -numa node,mem is not supported by this"
> +                      " machine type");
> +            error_append_hint(errp, "Use -numa node,memdev instead");
> +            return;
> +        }
> +
>          numa_info[nodenr].node_mem = node->mem;
>          if (!qtest_enabled()) {
>              warn_report("Parameter -numa node,mem is deprecated,"
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 2128f3d6fe..a86136069c 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1960,7 +1960,6 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>      hc->unplug = pc_machine_device_unplug_cb;
>      mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;
>      mc->nvdimm_supported = true;
> -    mc->numa_mem_supported = true;
>      mc->default_ram_id = "pc.ram";
>  
>      object_class_property_add(oc, PC_MACHINE_DEVMEM_REGION_SIZE, "int",
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index f66e1d73ce..8955436efa 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -438,6 +438,7 @@ static void pc_i440fx_5_0_machine_options(MachineClass *m)
>      pc_i440fx_5_1_machine_options(m);
>      m->alias = NULL;
>      m->is_default = false;
> +    m->numa_mem_supported = true;
>      compat_props_add(m->compat_props, hw_compat_5_0, hw_compat_5_0_len);
>      compat_props_add(m->compat_props, pc_compat_5_0, pc_compat_5_0_len);
>  }
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 4ba8ac8774..af6b32adb7 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -366,6 +366,7 @@ static void pc_q35_5_0_machine_options(MachineClass *m)
>  {
>      pc_q35_5_1_machine_options(m);
>      m->alias = NULL;
> +    m->numa_mem_supported = true;
>      compat_props_add(m->compat_props, hw_compat_5_0, hw_compat_5_0_len);
>      compat_props_add(m->compat_props, pc_compat_5_0, pc_compat_5_0_len);
>  }
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 3b1a5ed865..210d61d1b3 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4511,7 +4511,6 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
>       * in which LMBs are represented and hot-added
>       */
>      mc->numa_mem_align_shift = 28;
> -    mc->numa_mem_supported = true;
>      mc->auto_enable_numa = true;
>  
>      smc->default_caps.caps[SPAPR_CAP_HTM] = SPAPR_CAP_OFF;
> @@ -4599,6 +4598,7 @@ static void spapr_machine_5_0_class_options(MachineClass *mc)
>  {
>      spapr_machine_5_1_class_options(mc);
>      compat_props_add(mc->compat_props, hw_compat_5_0, hw_compat_5_0_len);
> +    mc->numa_mem_supported = true;
>  }
>  
>  DEFINE_SPAPR_MACHINE(5_0, "5.0", false);
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 93bde2bbc8..196f468786 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -239,10 +239,11 @@ SRST
>          -numa node,nodeid=0 -numa node,nodeid=1 \
>          -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
>  
> -    '\ ``mem``\ ' assigns a given RAM amount to a node. '\ ``memdev``\ '
> -    assigns RAM from a given memory backend device to a node. If
> -    '\ ``mem``\ ' and '\ ``memdev``\ ' are omitted in all nodes, RAM is
> -    split equally between them.
> +    Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported
> +    for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from
> +    a given memory backend device to a node. If '\ ``mem``\ ' and
> +    '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them.
> +
>  
>      '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive.
>      Furthermore, if one node uses '\ ``memdev``\ ', all of them have to
> -- 
> 2.26.2




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