Re: [PATCH libdrm] amdgpu: add amdgpu_bo_handle_type_kms_noimport

["Michel Dänzer" <michel-otUistvHUpPR7s880joybQ@public.gmane.org>]

On 2018-07-17 09:59 AM, Christian König wrote:
> Am 17.07.2018 um 09:46 schrieb Michel Dänzer:
>> On 2018-07-17 09:33 AM, Christian König wrote:
>>> Am 17.07.2018 um 09:26 schrieb Michel Dänzer:
>>>> On 2018-07-17 08:50 AM, Christian König wrote:
>>>>> Am 16.07.2018 um 18:05 schrieb Michel Dänzer:
>>>>>> On 2018-07-13 08:47 PM, Marek Olšák wrote:
>>>>>> [SNIP]
>>>>>> Other opinions?
>>>>> I understand the reason why Marek wants to do this, but I agree that
>>>>> this is a little bit dangerous if used incorrectly.
>>>>>
>>>>> On the other hand I don't see any other way to sanely handle it
>>>>> either.
>>>> Sanely handle what exactly? :) I still haven't seen any description of
>>>> an actual problem, other than "the handle is stored in the hash table".
>>> Well the problem is that it's not "the handle" but rather "all handles"
>>> which are now stored in the hash table.
>>>
>>> To begin with that is quite a bunch of wasted memory, not talking about
>>> the extra CPU cycles.
>> All that should be needed is one struct list_head per BO, 16 bytes on
>> 64-bit.
> 
> +malloc overhead and that for *every* BO the application/driver
> allocated.

The struct list_head can be stored in struct amdgpu_bo, no additional
malloc necessary.


> The last time I looked we could easily have a few thousands of that
> (but not in the same CS).
> 
> So I would guess that the wasted memory can easily be in the lower kb
> range, compared to adding just a flag that we never going to import the
> handle again.

I wouldn't call the memory "wasted", as it serves a clear purpose.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer
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