[AMD Official Use Only]
>-----Original Message-----
>From: Koenig, Christian <Christian.Koenig@xxxxxxx>
>Sent: Thursday, September 23, 2021 8:24 PM
>To: Yu, Lang <Lang.Yu@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>Cc: Kuehling, Felix <Felix.Kuehling@xxxxxxx>; Christian K nig
><C3B6christian.koenig@xxxxxxx>; Huang, Ray <Ray.Huang@xxxxxxx>
>Subject: Re: [PATCH] drm/kfd: fix ttm_bo_release warning
>
>Am 23.09.21 um 14:09 schrieb Yu, Lang:
>> [AMD Official Use Only]
>>
>>
>>
>>> -----Original Message-----
>>> From: Koenig, Christian <Christian.Koenig@xxxxxxx>
>>> Sent: Thursday, September 23, 2021 7:40 PM
>>> To: Yu, Lang <Lang.Yu@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>>> Cc: Kuehling, Felix <Felix.Kuehling@xxxxxxx>; Christian K nig
>>> <C3B6christian.koenig@xxxxxxx>; Huang, Ray <Ray.Huang@xxxxxxx>
>>> Subject: Re: [PATCH] drm/kfd: fix ttm_bo_release warning
>>>
>>>
>>>
>>> Am 23.09.21 um 11:44 schrieb Lang Yu:
>>>> If a BO is pinned, unpin it before freeing it.
>>>>
>>>> Call Trace:
>>>> ttm_bo_put+0x30/0x50 [ttm]
>>>> amdgpu_bo_unref+0x1e/0x30 [amdgpu]
>>>> amdgpu_gem_object_free+0x34/0x50 [amdgpu]
>>>> drm_gem_object_free+0x1d/0x30 [drm]
>>>> amdgpu_amdkfd_gpuvm_free_memory_of_gpu+0x31f/0x3a0 [amdgpu]
>>>> kfd_process_device_free_bos+0xa3/0xf0 [amdgpu]
>>>> kfd_process_wq_release+0x224/0x2e0 [amdgpu]
>>>> process_one_work+0x220/0x3c0
>>>> worker_thread+0x4d/0x3f0
>>>> kthread+0x114/0x150
>>>> process_one_work+0x3c0/0x3c0
>>>> kthread_park+0x90/0x90
>>>> ret_from_fork+0x22/0x30
>>>>
>>>> Signed-off-by: Lang Yu <lang.yu@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 3 +++
>>>> 1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> index 2d6b2d77b738..7e693b064072 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> @@ -1567,6 +1567,9 @@ int
>amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
>>>> pr_debug("Release VA 0x%llx - 0x%llx\n", mem->va,
>>>> mem->va + bo_size * (1 + mem->aql_queue));
>>>>
>>>> + if (mem->bo->tbo.pin_count)
>>>> + amdgpu_bo_unpin(mem->bo);
>>>> +
>>> NAK, using mem->bo->tbo.pin_count like this is illegal.
>> I didn't get your point. I referred to function-"void
>> amdgpu_bo_unpin(struct amdgpu_bo *bo)", which uses it like this.
>
>What amdgpu_bo_unpin() does is the following:
>
> ttm_bo_unpin(&bo->tbo);
> if (bo->tbo.pin_count)
> return;
>....
>
>In other words we take further actions based on if the buffer us is still pinned or
>not after an unpin operation.
>
>What you try to do here is unpinning the BO when it is pinned independent if
>somebody else or our code has pinned it before.
Hi Christian,
Thanks for your explanation and advice. I got your point.
Actually, these BOs are allocated and pinned during a kfd process lifecycle.
I will try to add a flag into struct kgd_mem to indicate which BO is pined
and should be unpinned. Which will make amdgpu_bo_pin/amdgpu_bo_unpin
calls balanced. Thanks!
Regards,
Lang
>
>That can lead to all kind of problems and is clearly illegal.
>
>>> Where was the BO pinned in the first place?
>> I found two places:
>>
>> ret = kfd_process_alloc_gpuvm(pdd, qpd->ib_base, PAGE_SIZE, flags,
>> &kaddr);
>>
>> ret = kfd_process_alloc_gpuvm(pdd, qpd->cwsr_base,
>> KFD_CWSR_TBA_TMA_SIZE, flags, &kaddr);
>
>Well then you need to figure out where that memory is freed again and place the
>unpin appropriately.
>
>General rule of thumb is that calls to amdgpu_bo_pin/amdgpu_bo_unpin should
>be balanced.
>
>Regards,
>Christian.
>
>> Regards,
>> Lang
>>
>>> Christian.
>>>
>>>> ret = unreserve_bo_and_vms(&ctx, false, false);
>>>>
>>>> /* Remove from VM internal data structures */
