[PATCH] staging: android: ion: Add chunk heap initialization

Laura Abbott labbott at redhat.com
Tue Nov 27 19:20:58 UTC 2018


On 11/26/18 10:43 AM, Alexey Skidanov wrote:
> 
> 
> On 11/26/18 6:39 PM, Laura Abbott wrote:
>> On 11/25/18 2:02 PM, Alexey Skidanov wrote:
>>>
>>>
>>> On 11/25/18 11:40 PM, Laura Abbott wrote:
>>>> On 11/25/18 1:22 PM, Alexey Skidanov wrote:
>>>>>
>>>>>
>>>>> On 11/25/18 10:51 PM, Laura Abbott wrote:
>>>>>> On 11/11/18 11:29 AM, Alexey Skidanov wrote:
>>>>>>> Create chunk heap of specified size and base address by adding
>>>>>>> "ion_chunk_heap=size at start" kernel boot parameter.
>>>>>>>
>>>>>>> Signed-off-by: Alexey Skidanov <alexey.skidanov at intel.com>
>>>>>>> ---
>>>>>>>      drivers/staging/android/ion/ion_chunk_heap.c | 40
>>>>>>> ++++++++++++++++++++++++++++
>>>>>>>      1 file changed, 40 insertions(+)
>>>>>>>
>>>>>>> diff --git a/drivers/staging/android/ion/ion_chunk_heap.c
>>>>>>> b/drivers/staging/android/ion/ion_chunk_heap.c
>>>>>>> index 159d72f..67573aa4 100644
>>>>>>> --- a/drivers/staging/android/ion/ion_chunk_heap.c
>>>>>>> +++ b/drivers/staging/android/ion/ion_chunk_heap.c
>>>>>>> @@ -135,6 +135,7 @@ struct ion_heap *ion_chunk_heap_create(struct
>>>>>>> ion_platform_heap *heap_data)
>>>>>>>          }
>>>>>>>          chunk_heap->base = heap_data->base;
>>>>>>>          chunk_heap->size = heap_data->size;
>>>>>>> +    chunk_heap->heap.name = heap_data->name;
>>>>>>>          chunk_heap->allocated = 0;
>>>>>>>            gen_pool_add(chunk_heap->pool, chunk_heap->base,
>>>>>>> heap_data->size, -1);
>>>>>>> @@ -151,3 +152,42 @@ struct ion_heap *ion_chunk_heap_create(struct
>>>>>>> ion_platform_heap *heap_data)
>>>>>>>          return ERR_PTR(ret);
>>>>>>>      }
>>>>>>>      +static u64 base;
>>>>>>> +static u64 size;
>>>>>>> +
>>>>>>> +static int __init setup_heap(char *param)
>>>>>>> +{
>>>>>>> +    char *p, *pp;
>>>>>>> +
>>>>>>> +    size = memparse(param, &p);
>>>>>>> +    if (param == p)
>>>>>>> +        return -EINVAL;
>>>>>>> +
>>>>>>> +    if (*p == '@')
>>>>>>> +        base = memparse(p + 1, &pp);
>>>>>>> +    else
>>>>>>> +        return -EINVAL;
>>>>>>> +
>>>>>>> +    if (p == pp)
>>>>>>> +        return -EINVAL;
>>>>>>> +
>>>>>>> +    return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +__setup("ion_chunk_heap=", setup_heap);
>>>>>>> +
>>>>>>> +static int ion_add_chunk_heap(void)
>>>>>>> +{
>>>>>>> +    struct ion_heap *heap;
>>>>>>> +    struct ion_platform_heap plat_heap = {.base = base,
>>>>>>> +                          .size = size,
>>>>>>> +                          .name = "chunk_heap",
>>>>>>> +                          .priv = (void *)PAGE_SIZE};
>>>>>>> +    heap = ion_chunk_heap_create(&plat_heap);
>>>>>>> +    if (heap)
>>>>>>> +        ion_device_add_heap(heap);
>>>>>>> +
>>>>>>> +    return 0;
>>>>>>> +}
>>>>>>> +device_initcall(ion_add_chunk_heap);
>>>>>>> +
>>>>>>>
>>>>>>
>>>>>> This solves a problem but not enough of the problem.
>>>>>>
>>>>>> We need to be able to support more than one chunk/carveout
>>>>>> heap.
>>>>> This is easy to support.
>>>>> This also assumes that the memory has already been
>>>>>> reserved/placed and that you know the base and size to
>>>>>> pass on the command line. Part of the issue with the carveout
>>>>>> heaps is that we need a way to tell the kernel to reserve
>>>>>> the memory early enough and then get that information to
>>>>>> Ion. Hard coding memory locations tends to be buggy from
>>>>>> my past experience with Ion.
>>>>> memmap= kernel option marks the memory region(s) as reserved (Zone
>>>>> Allocator doesn't use this memory region(s)). So the heap(s) may manage
>>>>> this memory region(s).
>>>>
>>>> memmap= is x86 only. I really don't like using the command line for
>>>> specifying the base/size as it seems likely to conflict with platforms
>>>> that rely on devicetree for reserving memory regions.
>>>>
>>>> Thanks,
>>>> Laura
>>>>
>>> I see ... So probably the better way is the one similar to this
>>> https://elixir.bootlin.com/linux/latest/source/kernel/dma/contiguous.c#L245
>>>
>>> ?
>>>
>>
>> Correct. For platforms that need devicetree, we need a way to specify
>> that a region should become an Ion heap. I went through a similar
>> exercise with CMA heaps before I kind of gave up on figuring out a
>> binding and just had Ion enumerate all CMA heaps. We do still need
>> a solution to work with non-DT platforms as well so whatever we
>> come up with needs to plausibly work for both cases. Your solution
>> would cover the non-DT case but I'd really like to make sure we
>> at least have a path forward for the devicetree case as well.
> 
> I would say that we have the following steps to consider:
> 
> 1. Memory reservation. The suggested solution doesn't care how it's done.
> 
> 2. Per-heap information passing to the Kernel. It's different for DT and
> non-DT cases.
> 
> 3. Heap objects instantiation. The DT and non-DT cases have different
> ways/formats to pass this per-heap information. But once the parsing is
> done, the rest of the code is common.
> 
> I think it clearly defines the steps covering both cases. What do you think?
> 

Yes, that sounds about right.

> Thanks,
> Alexey
>>
>> Thanks,
>> Laura
>>
>>> Thanks,
>>> Alexey
>>>
>>>>>>
>>>>>> If you'd like to see about coming up with a complete solution,
>>>>>> feel free to resubmit but I'm still strongly considering
>>>>>> removing these heaps.
>>>>>>
>>>>> I will add the multiple heaps support and resubmit the patch
>>>>>> Thanks,
>>>>>> Laura
>>>>> Thanks,
>>>>> Alexey
>>>>>
>>>>
>>



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