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

[zhoucm1 <david1.zhou-5C7GfCeVMHo@public.gmane.org>]

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

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