On 2017å¹´10æ??17æ?¥ 15:46, Christian König wrote:
> Am 17.10.2017 um 06:11 schrieb Chunming Zhou:
>>
>>
>> On 2017å¹´10æ??16æ?¥ 19:40, Christian König wrote:
>>> Am 16.10.2017 um 11:42 schrieb Chunming Zhou:
>>>>
>>>>
>>>> On 2017å¹´10æ??16æ?¥ 17:26, Christian König wrote:
>>>>> From: Christian König <christian.koenig at amd.com>
>>>>>
>>>>> While binding BOs to GART we need to allow a bit overcommit in the
>>>>> GTT
>>>>> domain.
>>>> If allowing overcommit, will the new node not over the GART mc
>>>> range? Which is also allowed?
>>> No that is checked separately by drm_mm_insert_node_in_range().
>>>
>>> This is just to cover the case when we have a BO in GTT space which
>>> needs to be bound into the GART table.
>> Sorry, I missed that even gart BO is also without node during creating.
>> One nitpick, atomic64_sub(mem->num_pages, &mgr->available) will be
>> calculated twice for one gart bo create and pin, which results in
>> available isn't correct.
>
> Yeah, that is true but not as problematic as you think.
>
> The BO is transfered from the old mem object (without GART mapping) to
> the new mem object (with GART mapping). While doing this the old mem
> object is released, so we actually don't leak the memory.
>
> It's just that for a moment the BO is accounted twice, once for the
> old location and once for the new one.
If in memory pressure, I think we could allocate memory over the mgr
limitation.
For example, the limitation is 1024M, the BO allocation is 800M, when
the second counting, the available will be -576M, since available is
unsigned, if another process allocation(800M) is coming at this moment,
the bo_create is still successful, the binding will be fail. But the
total allocation will be over the mgr limitation.
Regards,
David Zhou
>
> But we had that behavior previously as well, so that is not something
> introduced with this patch.
>
> Regards,
> Christian.
>
>>
>> Regards,
>> David Zhou
>>>
>>> Regards,
>>> Christian.
>>>
>>>>
>>>> Regards,
>>>> David Zhou
>>>>> Â Otherwise we can never use the full GART space when GART
>>>>> size=GTT size.
>>>>>
>>>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>>>> ---
>>>>> Â drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c | 8 +++++---
>>>>> Â 1 file changed, 5 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> index 0d15eb7d31d7..33535d347734 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>>>> @@ -169,7 +169,8 @@ static int amdgpu_gtt_mgr_new(struct
>>>>> ttm_mem_type_manager *man,
>>>>> Â Â Â Â Â int r;
>>>>> Â Â Â Â Â Â Â spin_lock(&mgr->lock);
>>>>> -Â Â Â if (atomic64_read(&mgr->available) < mem->num_pages) {
>>>>> +Â Â Â if ((&tbo->mem == mem || tbo->mem.mem_type != TTM_PL_TT) &&
>>>>> +Â Â Â Â Â Â Â atomic64_read(&mgr->available) < mem->num_pages) {
>>>>> Â Â Â Â Â Â Â Â Â spin_unlock(&mgr->lock);
>>>>> Â Â Â Â Â Â Â Â Â return 0;
>>>>> Â Â Â Â Â }
>>>>> @@ -244,8 +245,9 @@ static void amdgpu_gtt_mgr_del(struct
>>>>> ttm_mem_type_manager *man,
>>>>> Â uint64_t amdgpu_gtt_mgr_usage(struct ttm_mem_type_manager *man)
>>>>> Â {
>>>>> Â Â Â Â Â struct amdgpu_gtt_mgr *mgr = man->priv;
>>>>> +Â Â Â s64 result = man->size - atomic64_read(&mgr->available);
>>>>> Â -Â Â Â return (u64)(man->size - atomic64_read(&mgr->available)) *
>>>>> PAGE_SIZE;
>>>>> +Â Â Â return (result > 0 ? result : 0) * PAGE_SIZE;
>>>>> Â }
>>>>> Â Â Â /**
>>>>> @@ -265,7 +267,7 @@ static void amdgpu_gtt_mgr_debug(struct
>>>>> ttm_mem_type_manager *man,
>>>>> Â Â Â Â Â drm_mm_print(&mgr->mm, printer);
>>>>> Â Â Â Â Â spin_unlock(&mgr->lock);
>>>>> Â -Â Â Â drm_printf(printer, "man size:%llu pages, gtt
>>>>> available:%llu pages, usage:%lluMB\n",
>>>>> +Â Â Â drm_printf(printer, "man size:%llu pages, gtt available:%lld
>>>>> pages, usage:%lluMB\n",
>>>>> Â Â Â Â Â Â Â Â Â Â Â Â man->size, (u64)atomic64_read(&mgr->available),
>>>>> Â Â Â Â Â Â Â Â Â Â Â Â amdgpu_gtt_mgr_usage(man) >> 20);
>>>>> Â }
>>>>
>>>
>>
>
