[PATCH 1/3] drm/amdgpu: fix gtt mgr available statistics

[Christian König]

Am 19.04.2017 um 11:15 schrieb zhoucm1:
>
>
> On 2017年04月19日 14:59, Christian König wrote:
>> Am 19.04.2017 um 08:52 schrieb zhoucm1:
>>>
>>>
>>> On 2017年04月19日 14:38, Christian König wrote:
>>>> Am 19.04.2017 um 05:50 schrieb Chunming Zhou:
>>>>> gtt_mgr_alloc is called by many places in local driver, while
>>>>> gtt_mgr_new is called by get_node in ttm.
>>>>
>>>> NAK, that can lead to over allocating the address space and we 
>>>> can't handle that during suspend/resume.
>>> I didn't get your mean here.
>>>
>>> Describe it first from my side, I found this issue on APU like 
>>> carrizo, vram is little, so gtt is used much more, we always found 
>>> the gtt cannot be used end up and results in Game failed to allocate 
>>> memory, but from dumping mm hole table, there are many free hole and 
>>> memory.
>>
>> In this case you need to increase the gartsize parameter to the 
>> kernel module. What is the default size chosen for this? Maybe we 
>> need to adjust that default.
>>
>>> The root cause is mgr->available statistic is incorrect, which 
>>> doesn't match dump mm table.
>>
>> That's actually correct. 
> There will be a problem here, memory not mapped in mm table won't be 
> able to evict by TTM.

Why do you think so? It's possible that we have a bug somewhere 
regarding this, but at least in theory that shouldn't be the case.

> The root cause is here, we need to find a solution for it.

Yeah, that sounds like the handling is buggy somehow.

Regards,
Christian.

> And yes, I agree your other opinions.
>
> Regards,
> David Zhou
>> We don't map all BOs in the GART domain into the actual GART table to 
>> avoid all the table operations.
>>
>>> I think mgr->available should only be changed when insert/free node.
>>
>> No, on suspend/resume we need to be able to add all BOs into the GART 
>> table. So with your change suspend/resume can potentially fail.
>>
>> Regards,
>> Christian.
>>
>>>
>>>
>>> Regards,
>>> David Zhou
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>>>
>>>>> Change-Id: Ia5a18a3b531a01ad7d47f40e08f778e7b94c048a
>>>>> Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
>>>>> ---
>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c | 11 +++++------
>>>>>   1 file changed, 5 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c 
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> index 69ab2ee..8a950a5 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> @@ -124,6 +124,8 @@ int amdgpu_gtt_mgr_alloc(struct 
>>>>> ttm_mem_type_manager *man,
>>>>>       r = drm_mm_insert_node_in_range_generic(&mgr->mm, node, 
>>>>> mem->num_pages,
>>>>>                           mem->page_alignment, 0,
>>>>>                           fpfn, lpfn, sflags, aflags);
>>>>> +    if (!r)
>>>>> +        mgr->available -= mem->num_pages;
>>>>>       spin_unlock(&mgr->lock);
>>>>>         if (!r) {
>>>>> @@ -160,7 +162,6 @@ static int amdgpu_gtt_mgr_new(struct 
>>>>> ttm_mem_type_manager *man,
>>>>>           spin_unlock(&mgr->lock);
>>>>>           return 0;
>>>>>       }
>>>>> -    mgr->available -= mem->num_pages;
>>>>>       spin_unlock(&mgr->lock);
>>>>>         node = kzalloc(sizeof(*node), GFP_KERNEL);
>>>>> @@ -187,9 +188,6 @@ static int amdgpu_gtt_mgr_new(struct 
>>>>> ttm_mem_type_manager *man,
>>>>>         return 0;
>>>>>   err_out:
>>>>> -    spin_lock(&mgr->lock);
>>>>> -    mgr->available += mem->num_pages;
>>>>> -    spin_unlock(&mgr->lock);
>>>>>         return r;
>>>>>   }
>>>>> @@ -214,9 +212,10 @@ static void amdgpu_gtt_mgr_del(struct 
>>>>> ttm_mem_type_manager *man,
>>>>>           return;
>>>>>         spin_lock(&mgr->lock);
>>>>> -    if (node->start != AMDGPU_BO_INVALID_OFFSET)
>>>>> +    if (node->start != AMDGPU_BO_INVALID_OFFSET) {
>>>>>           drm_mm_remove_node(node);
>>>>> -    mgr->available += mem->num_pages;
>>>>> +        mgr->available += mem->num_pages;
>>>>> +    }
>>>>>       spin_unlock(&mgr->lock);
>>>>>         kfree(node);
>>>>
>>>>
>>>
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>>> amd-gfx at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>
>>
>