From 32a354dc6c07d766e70b51f42a62d8cd479e3f82 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Tue, 9 Jun 2020 09:56:35 -0400 Subject: [PATCH] numa: forbid '-numa node, mem' for 5.1 and newer machine types 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 Reviewed-by: Michal Privoznik Reviewed-by: Michael S. Tsirkin Reviewed-by: Greg Kurz Message-Id: <20200609135635.761587-1-imammedo@redhat.com> Signed-off-by: Paolo Bonzini --- 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 728233a8ff..843ae71fc6 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -95,23 +95,6 @@ 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 The ``-realtime mlock=on|off`` argument has been replaced by the ``-overcommit mem-lock=on|off`` argument.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) ''''''''''''''''''''''''''''''''''''''''''''''''''''' @@ -553,3 +536,23 @@ 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`` was used to assign a part of +guest RAM to a NUMA node. But when using it, it's impossible to manage a specified +RAM chunk on the host side (like bind it to a host node, setting bind policy, ...), +so the guest ends up 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 actually manage node RAM on the host side. Use parameter ``memdev`` +with *memory-backend-ram* backend as 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. +New machine versions (since 5.1) will not accept the option but it will still +work with old machine types. User can check the 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 402c362c14..5aa8b87465 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -2320,7 +2320,6 @@ static void virt_machine_class_init(ObjectClass *oc, void *data) hc->plug = virt_machine_device_plug_cb; hc->unplug_request = virt_machine_device_unplug_request_cb; hc->unplug = virt_machine_device_unplug_cb; - mc->numa_mem_supported = true; mc->nvdimm_supported = true; mc->auto_enable_numa_with_memhp = true; mc->default_ram_id = "mach-virt.ram"; @@ -2434,6 +2433,7 @@ static void virt_machine_5_0_options(MachineClass *mc) { virt_machine_5_1_options(mc); compat_props_add(mc->compat_props, hw_compat_5_0, hw_compat_5_0_len); + mc->numa_mem_supported = true; } DEFINE_VIRT_MACHINE(5, 0) diff --git a/hw/core/numa.c b/hw/core/numa.c index 5f81900f88..2725886d06 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\n"); + 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 803bd52ca4..4af9679d03 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1980,7 +1980,6 @@ 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_MAX_RAM_BELOW_4G, "size", diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 1497d0e4ae..1d832b2878 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -441,6 +441,7 @@ 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 46cd06524c..047ea8db28 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -369,6 +369,7 @@ 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 bd9345cdac..4c185bcc13 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -4510,7 +4510,6 @@ 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; @@ -4598,6 +4597,7 @@ 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