Re: [PATCH v3] memory: Have 'info mtree' remove duplicated Address Space information

[Philippe Mathieu-Daudé]

On 8/23/21 11:20 AM, David Hildenbrand wrote:
> On 23.08.21 10:54, Philippe Mathieu-Daudé wrote:
>> Per Peter Maydell [*]:
>>
>>    'info mtree' monitor command was designed on the assumption that
>>    there's really only one or two interesting address spaces, and
>>    with more recent developments that's just not the case any more.
>>
>> Similarly about how the FlatView are sorted using a GHashTable,
>> sort the AddressSpace objects to remove the duplications (AS
>> using the same root MemoryRegion).
>>
>> This drastically reduce 'info mtree' on some boards.
> 
> s/reduce/reduces the output of/
> 
>>
>> Before:
>>
>>    $ (echo info mtree; echo q) \
>>      | qemu-system-aarch64 -S -monitor stdio -M raspi3b \
>>      | wc -l
>>    423
>>
>> After:
>>
>>    $ (echo info mtree; echo q) \
>>      | qemu-system-aarch64 -S -monitor stdio -M raspi3b \
>>      | wc -l
>>    106
>>
>>    (qemu) info mtree
>>    address-space: I/O
>>      0000000000000000-000000000000ffff (prio 0, i/o): io
>>
>>    address-space: cpu-memory-0
>>    address-space: cpu-memory-1
>>    address-space: cpu-memory-2
>>    address-space: cpu-memory-3
>>    address-space: cpu-secure-memory-0
>>    address-space: cpu-secure-memory-1
>>    address-space: cpu-secure-memory-2
>>    address-space: cpu-secure-memory-3
> 
> We can still distinguish from a completely empty AS, because we don't
> have an empty line here, correct?

Yes:

(qemu) info mtree
address-space: I/O
  0000000000000000-000000000000ffff (prio 0, i/o): io

address-space shared 4 times:
  - bcm2835-dma-memory
  - bcm2835-fb-memory
  - bcm2835-property-memory
  - dwc2
  0000000000000000-00000000ffffffff (prio 0, i/o): bcm2835-gpu
    0000000000000000-000000003fffffff (prio 0, ram): alias
bcm2835-gpu-ram-alias[*] @ram 0000000000000000-000000003fffffff
    0000000040000000-000000007fffffff (prio 0, ram): alias
bcm2835-gpu-ram-alias[*] @ram 0000000000000000-000000003fffffff
    000000007e000000-000000007effffff (prio 1, i/o): alias
bcm2835-peripherals @bcm2835-peripherals 0000000000000000-0000000000ffffff
    0000000080000000-00000000bfffffff (prio 0, ram): alias
bcm2835-gpu-ram-alias[*] @ram 0000000000000000-000000003fffffff
    00000000c0000000-00000000ffffffff (prio 0, ram): alias
bcm2835-gpu-ram-alias[*] @ram 0000000000000000-000000003fffffff

address-space: bcm2835-mbox-memory
  0000000000000000-000000000000008f (prio 0, i/o): bcm2835-mbox
    0000000000000010-000000000000001f (prio 0, i/o): bcm2835-fb
    0000000000000080-000000000000008f (prio 0, i/o): bcm2835-property

[...]