Re: [PATCH 5/5] drm/amdgpu: fix shadow BO restoring

Christian König
2018-09-14T11:54:33Z

Am 13.09.2018 um 11:29 schrieb Zhang, Jerry(Junwei):
> On 09/11/2018 05:56 PM, Christian König wrote:
>> Don't grab the reservation lock any more and simplify the handling quite
>> a bit.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 109
>> ++++++++---------------------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c |  46 ++++--------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.h |   8 +--
>>   3 files changed, 43 insertions(+), 120 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 5eba66ecf668..20bb702f5c7f 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -2940,54 +2940,6 @@ static int
>> amdgpu_device_ip_post_soft_reset(struct amdgpu_device *adev)
>>       return 0;
>>   }
>>   -/**
>> - * amdgpu_device_recover_vram_from_shadow - restore shadowed VRAM
>> buffers
>> - *
>> - * @adev: amdgpu_device pointer
>> - * @ring: amdgpu_ring for the engine handling the buffer operations
>> - * @bo: amdgpu_bo buffer whose shadow is being restored
>> - * @fence: dma_fence associated with the operation
>> - *
>> - * Restores the VRAM buffer contents from the shadow in GTT. Used to
>> - * restore things like GPUVM page tables after a GPU reset where
>> - * the contents of VRAM might be lost.
>> - * Returns 0 on success, negative error code on failure.
>> - */
>> -static int amdgpu_device_recover_vram_from_shadow(struct
>> amdgpu_device *adev,
>> -                          struct amdgpu_ring *ring,
>> -                          struct amdgpu_bo *bo,
>> -                          struct dma_fence **fence)
>> -{
>> -    uint32_t domain;
>> -    int r;
>> -
>> -    if (!bo->shadow)
>> -        return 0;
>> -
>> -    r = amdgpu_bo_reserve(bo, true);
>> -    if (r)
>> -        return r;
>> -    domain = amdgpu_mem_type_to_domain(bo->tbo.mem.mem_type);
>> -    /* if bo has been evicted, then no need to recover */
>> -    if (domain == AMDGPU_GEM_DOMAIN_VRAM) {
>> -        r = amdgpu_bo_validate(bo->shadow);
>> -        if (r) {
>> -            DRM_ERROR("bo validate failed!\n");
>> -            goto err;
>> -        }
>> -
>> -        r = amdgpu_bo_restore_from_shadow(adev, ring, bo,
>> -                         NULL, fence, true);
>> -        if (r) {
>> -            DRM_ERROR("recover page table failed!\n");
>> -            goto err;
>> -        }
>> -    }
>> -err:
>> -    amdgpu_bo_unreserve(bo);
>> -    return r;
>> -}
>> -
>>   /**
>>    * amdgpu_device_recover_vram - Recover some VRAM contents
>>    *
>> @@ -2996,16 +2948,15 @@ static int
>> amdgpu_device_recover_vram_from_shadow(struct amdgpu_device *adev,
>>    * Restores the contents of VRAM buffers from the shadows in GTT.
>> Used to
>>    * restore things like GPUVM page tables after a GPU reset where
>>    * the contents of VRAM might be lost.
>> - * Returns 0 on success, 1 on failure.
>> + *
>> + * Returns:
>> + * 0 on success, negative error code on failure.
>>    */
>>   static int amdgpu_device_recover_vram(struct amdgpu_device *adev)
>>   {
>> -    struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
>> -    struct amdgpu_bo *bo, *tmp;
>>       struct dma_fence *fence = NULL, *next = NULL;
>> -    long r = 1;
>> -    int i = 0;
>> -    long tmo;
>> +    struct amdgpu_bo *shadow;
>> +    long r = 1, tmo;
>>         if (amdgpu_sriov_runtime(adev))
>>           tmo = msecs_to_jiffies(8000);
>> @@ -3014,44 +2965,40 @@ static int amdgpu_device_recover_vram(struct
>> amdgpu_device *adev)
>>         DRM_INFO("recover vram bo from shadow start\n");
>>       mutex_lock(&adev->shadow_list_lock);
>> -    list_for_each_entry_safe(bo, tmp, &adev->shadow_list,
>> shadow_list) {
>> -        next = NULL;
>> -        amdgpu_device_recover_vram_from_shadow(adev, ring, bo, &next);
>> +    list_for_each_entry(shadow, &adev->shadow_list, shadow_list) {
>> +
>> +        /* No need to recover an evicted BO */
>> +        if (shadow->tbo.mem.mem_type != TTM_PL_TT ||
>> +            shadow->parent->tbo.mem.mem_type != TTM_PL_VRAM)
> is there a change that shadow bo evicted to other domain?
> like SYSTEM?

Yes, that's why I test "!= TTM_PL_TT" here.

What can happen is that either the shadow or the page table or page
directory is evicted.

But in this case we don't need to restore anything because of patch #1
in this series.

Regards,
Christian.

>
> Regards,
> Jerry
>> +            continue;
>> +
>> +        r = amdgpu_bo_restore_shadow(shadow, &next);
>> +        if (r)
>> +            break;
>> +
>>           if (fence) {
>>               r = dma_fence_wait_timeout(fence, false, tmo);
>> -            if (r == 0)
>> -                pr_err("wait fence %p[%d] timeout\n", fence, i);
>> -            else if (r < 0)
>> -                pr_err("wait fence %p[%d] interrupted\n", fence, i);
>> -            if (r < 1) {
>> -                dma_fence_put(fence);
>> -                fence = next;
>> +            dma_fence_put(fence);
>> +            fence = next;
>> +            if (r <= 0)
>>                   break;
>> -            }
>> -            i++;
>> +        } else {
>> +            fence = next;
>>           }
>> -
>> -        dma_fence_put(fence);
>> -        fence = next;
>>       }
>>       mutex_unlock(&adev->shadow_list_lock);
>>   -    if (fence) {
>> -        r = dma_fence_wait_timeout(fence, false, tmo);
>> -        if (r == 0)
>> -            pr_err("wait fence %p[%d] timeout\n", fence, i);
>> -        else if (r < 0)
>> -            pr_err("wait fence %p[%d] interrupted\n", fence, i);
>> -
>> -    }
>> +    if (fence)
>> +        tmo = dma_fence_wait_timeout(fence, false, tmo);
>>       dma_fence_put(fence);
>>   -    if (r > 0)
>> -        DRM_INFO("recover vram bo from shadow done\n");
>> -    else
>> +    if (r <= 0 || tmo <= 0) {
>>           DRM_ERROR("recover vram bo from shadow failed\n");
>> +        return -EIO;
>> +    }
>>   -    return (r > 0) ? 0 : 1;
>> +    DRM_INFO("recover vram bo from shadow done\n");
>> +    return 0;
>>   }
>>     /**
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 3a6f92de5504..5b6d5fcc2151 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -537,7 +537,7 @@ static int amdgpu_bo_create_shadow(struct
>> amdgpu_device *adev,
>>       if (!r) {
>>           bo->shadow->parent = amdgpu_bo_ref(bo);
>>           mutex_lock(&adev->shadow_list_lock);
>> -        list_add_tail(&bo->shadow_list, &adev->shadow_list);
>> +        list_add_tail(&bo->shadow->shadow_list, &adev->shadow_list);
>>           mutex_unlock(&adev->shadow_list_lock);
>>       }
>>   @@ -669,13 +669,10 @@ int amdgpu_bo_validate(struct amdgpu_bo *bo)
>>   }
>>     /**
>> - * amdgpu_bo_restore_from_shadow - restore an &amdgpu_bo buffer object
>> - * @adev: amdgpu device object
>> - * @ring: amdgpu_ring for the engine handling the buffer operations
>> - * @bo: &amdgpu_bo buffer to be restored
>> - * @resv: reservation object with embedded fence
>> + * amdgpu_bo_restore_shadow - restore an &amdgpu_bo shadow
>> + *
>> + * @shadow: &amdgpu_bo shadow to be restored
>>    * @fence: dma_fence associated with the operation
>> - * @direct: whether to submit the job directly
>>    *
>>    * Copies a buffer object's shadow content back to the object.
>>    * This is used for recovering a buffer from its shadow in case of
>> a gpu
>> @@ -684,36 +681,19 @@ int amdgpu_bo_validate(struct amdgpu_bo *bo)
>>    * Returns:
>>    * 0 for success or a negative error code on failure.
>>    */
>> -int amdgpu_bo_restore_from_shadow(struct amdgpu_device *adev,
>> -                  struct amdgpu_ring *ring,
>> -                  struct amdgpu_bo *bo,
>> -                  struct reservation_object *resv,
>> -                  struct dma_fence **fence,
>> -                  bool direct)
>> +int amdgpu_bo_restore_shadow(struct amdgpu_bo *shadow, struct
>> dma_fence **fence)
>>     {
>> -    struct amdgpu_bo *shadow = bo->shadow;
>> -    uint64_t bo_addr, shadow_addr;
>> -    int r;
>> -
>> -    if (!shadow)
>> -        return -EINVAL;
>> -
>> -    bo_addr = amdgpu_bo_gpu_offset(bo);
>> -    shadow_addr = amdgpu_bo_gpu_offset(bo->shadow);
>> -
>> -    r = reservation_object_reserve_shared(bo->tbo.resv);
>> -    if (r)
>> -        goto err;
>> +    struct amdgpu_device *adev = amdgpu_ttm_adev(shadow->tbo.bdev);
>> +    struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
>> +    uint64_t shadow_addr, parent_addr;
>>   -    r = amdgpu_copy_buffer(ring, shadow_addr, bo_addr,
>> -                   amdgpu_bo_size(bo), resv, fence,
>> -                   direct, false);
>> -    if (!r)
>> -        amdgpu_bo_fence(bo, *fence, true);
>> +    shadow_addr = amdgpu_bo_gpu_offset(shadow);
>> +    parent_addr = amdgpu_bo_gpu_offset(shadow->parent);
>>   -err:
>> -    return r;
>> +    return amdgpu_copy_buffer(ring, shadow_addr, parent_addr,
>> +                  amdgpu_bo_size(shadow), NULL, fence,
>> +                  true, false);
>>   }
>>     /**
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> index 907fdf46d895..363db417fb2e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
>> @@ -273,12 +273,8 @@ int amdgpu_bo_backup_to_shadow(struct
>> amdgpu_device *adev,
>>                      struct reservation_object *resv,
>>                      struct dma_fence **fence, bool direct);
>>   int amdgpu_bo_validate(struct amdgpu_bo *bo);
>> -int amdgpu_bo_restore_from_shadow(struct amdgpu_device *adev,
>> -                  struct amdgpu_ring *ring,
>> -                  struct amdgpu_bo *bo,
>> -                  struct reservation_object *resv,
>> -                  struct dma_fence **fence,
>> -                  bool direct);
>> +int amdgpu_bo_restore_shadow(struct amdgpu_bo *shadow,
>> +                 struct dma_fence **fence);
>>   uint32_t amdgpu_bo_get_preferred_pin_domain(struct amdgpu_device
>> *adev,
>>                           uint32_t domain);