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[PATCH 6/7] hw/i386/pc_{q35, piix}: Minimize usage of get_system_memory()

Bernhard Beschow posted 7 patches 3 years ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
There is a newer version of this series
[PATCH 6/7] hw/i386/pc_{q35, piix}: Minimize usage of get_system_memory()
Posted by Bernhard Beschow 3 years ago 
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 hw/i386/pc_piix.c | 2 +-
 hw/i386/pc_q35.c  | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index ee9d9a4175..5bde4533cc 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -241,7 +241,7 @@ static void pc_init1(MachineState *machine,
         isa_bus = ISA_BUS(qdev_get_child_bus(DEVICE(piix3), "isa.0"));
     } else {
         pci_bus = NULL;
-        isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
+        isa_bus = isa_bus_new(NULL, system_memory, system_io,
                               &error_abort);
         i8257_dma_init(isa_bus, 0);
         pcms->hpet_enabled = false;
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index a97846ab9b..b97979bebb 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -124,6 +124,7 @@ static void pc_q35_init(MachineState *machine)
     DeviceState *lpc_dev;
     BusState *idebus[MAX_SATA_PORTS];
     ISADevice *rtc_state;
+    MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *system_io = get_system_io();
     MemoryRegion *pci_memory;
     MemoryRegion *rom_memory;
@@ -191,7 +192,7 @@ static void pc_q35_init(MachineState *machine)
         rom_memory = pci_memory;
     } else {
         pci_memory = NULL;
-        rom_memory = get_system_memory();
+        rom_memory = system_memory;
     }
 
     pc_guest_info_init(pcms);
@@ -214,7 +215,7 @@ static void pc_q35_init(MachineState *machine)
     }
 
     /* allocate ram and load rom/bios */
-    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory,
+    pc_memory_init(pcms, system_memory, rom_memory, &ram_memory,
                    pci_hole64_size);
 
     object_property_add_child(OBJECT(machine), "q35", OBJECT(phb));
@@ -223,7 +224,7 @@ static void pc_q35_init(MachineState *machine)
     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_PCI_MEM,
                              OBJECT(pci_memory), NULL);
     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_SYSTEM_MEM,
-                             OBJECT(get_system_memory()), NULL);
+                             OBJECT(system_memory), NULL);
     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_IO_MEM,
                              OBJECT(system_io), NULL);
     object_property_set_int(OBJECT(phb), PCI_HOST_BELOW_4G_MEM_SIZE,
-- 
2.39.1
Re: [PATCH 6/7] hw/i386/pc_{q35, piix}: Minimize usage of get_system_memory()
Posted by BALATON Zoltan 3 years ago 
On Fri, 27 Jan 2023, Bernhard Beschow wrote:
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>

Why? I'd rather replace locals with direct call to function as it's not 
expensive (just returns a global) and adding a local name to it is not 
much shorter so why do that?

Regards,
BALATON Zoltan

> ---
> hw/i386/pc_piix.c | 2 +-
> hw/i386/pc_q35.c  | 7 ++++---
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index ee9d9a4175..5bde4533cc 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -241,7 +241,7 @@ static void pc_init1(MachineState *machine,
>         isa_bus = ISA_BUS(qdev_get_child_bus(DEVICE(piix3), "isa.0"));
>     } else {
>         pci_bus = NULL;
> -        isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
> +        isa_bus = isa_bus_new(NULL, system_memory, system_io,
>                               &error_abort);
>         i8257_dma_init(isa_bus, 0);
>         pcms->hpet_enabled = false;
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index a97846ab9b..b97979bebb 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -124,6 +124,7 @@ static void pc_q35_init(MachineState *machine)
>     DeviceState *lpc_dev;
>     BusState *idebus[MAX_SATA_PORTS];
>     ISADevice *rtc_state;
> +    MemoryRegion *system_memory = get_system_memory();
>     MemoryRegion *system_io = get_system_io();
>     MemoryRegion *pci_memory;
>     MemoryRegion *rom_memory;
> @@ -191,7 +192,7 @@ static void pc_q35_init(MachineState *machine)
>         rom_memory = pci_memory;
>     } else {
>         pci_memory = NULL;
> -        rom_memory = get_system_memory();
> +        rom_memory = system_memory;
>     }
>
>     pc_guest_info_init(pcms);
> @@ -214,7 +215,7 @@ static void pc_q35_init(MachineState *machine)
>     }
>
>     /* allocate ram and load rom/bios */
> -    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory,
> +    pc_memory_init(pcms, system_memory, rom_memory, &ram_memory,
>                    pci_hole64_size);
>
>     object_property_add_child(OBJECT(machine), "q35", OBJECT(phb));
> @@ -223,7 +224,7 @@ static void pc_q35_init(MachineState *machine)
>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_PCI_MEM,
>                              OBJECT(pci_memory), NULL);
>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_SYSTEM_MEM,
> -                             OBJECT(get_system_memory()), NULL);
> +                             OBJECT(system_memory), NULL);
>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_IO_MEM,
>                              OBJECT(system_io), NULL);
>     object_property_set_int(OBJECT(phb), PCI_HOST_BELOW_4G_MEM_SIZE,
>
Re: [PATCH 6/7] hw/i386/pc_{q35, piix}: Minimize usage of get_system_memory()
Posted by Bernhard Beschow 3 years ago 

Am 27. Januar 2023 19:30:21 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Fri, 27 Jan 2023, Bernhard Beschow wrote:
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>
>Why? I'd rather replace locals with direct call to function as it's not expensive (just returns a global) and adding a local name to it is not much shorter so why do that?

The function has the assumption baked in to return a global which I'd like to factor out into a single variable assignment. This allows for easier experimentation with alternatives to global variables.

Moreover, extrating to a single variable mirrors how similar things are done in the pc and q35 machines.

Best regards,
Bernhard
>
>Regards,
>BALATON Zoltan
>
>> ---
>> hw/i386/pc_piix.c | 2 +-
>> hw/i386/pc_q35.c  | 7 ++++---
>> 2 files changed, 5 insertions(+), 4 deletions(-)
>> 
>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> index ee9d9a4175..5bde4533cc 100644
>> --- a/hw/i386/pc_piix.c
>> +++ b/hw/i386/pc_piix.c
>> @@ -241,7 +241,7 @@ static void pc_init1(MachineState *machine,
>>         isa_bus = ISA_BUS(qdev_get_child_bus(DEVICE(piix3), "isa.0"));
>>     } else {
>>         pci_bus = NULL;
>> -        isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
>> +        isa_bus = isa_bus_new(NULL, system_memory, system_io,
>>                               &error_abort);
>>         i8257_dma_init(isa_bus, 0);
>>         pcms->hpet_enabled = false;
>> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
>> index a97846ab9b..b97979bebb 100644
>> --- a/hw/i386/pc_q35.c
>> +++ b/hw/i386/pc_q35.c
>> @@ -124,6 +124,7 @@ static void pc_q35_init(MachineState *machine)
>>     DeviceState *lpc_dev;
>>     BusState *idebus[MAX_SATA_PORTS];
>>     ISADevice *rtc_state;
>> +    MemoryRegion *system_memory = get_system_memory();
>>     MemoryRegion *system_io = get_system_io();
>>     MemoryRegion *pci_memory;
>>     MemoryRegion *rom_memory;
>> @@ -191,7 +192,7 @@ static void pc_q35_init(MachineState *machine)
>>         rom_memory = pci_memory;
>>     } else {
>>         pci_memory = NULL;
>> -        rom_memory = get_system_memory();
>> +        rom_memory = system_memory;
>>     }
>> 
>>     pc_guest_info_init(pcms);
>> @@ -214,7 +215,7 @@ static void pc_q35_init(MachineState *machine)
>>     }
>> 
>>     /* allocate ram and load rom/bios */
>> -    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory,
>> +    pc_memory_init(pcms, system_memory, rom_memory, &ram_memory,
>>                    pci_hole64_size);
>> 
>>     object_property_add_child(OBJECT(machine), "q35", OBJECT(phb));
>> @@ -223,7 +224,7 @@ static void pc_q35_init(MachineState *machine)
>>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_PCI_MEM,
>>                              OBJECT(pci_memory), NULL);
>>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_SYSTEM_MEM,
>> -                             OBJECT(get_system_memory()), NULL);
>> +                             OBJECT(system_memory), NULL);
>>     object_property_set_link(OBJECT(phb), MCH_HOST_PROP_IO_MEM,
>>                              OBJECT(system_io), NULL);
>>     object_property_set_int(OBJECT(phb), PCI_HOST_BELOW_4G_MEM_SIZE,
>>

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