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

Huang Rui
2018-09-18T08:40:35Z

On Mon, Sep 17, 2018 at 07:42:38PM +0800, Christian König wrote:
> Am 17.09.2018 um 11:10 schrieb Huang Rui:
> > On Fri, Sep 14, 2018 at 03:42:57PM +0200, 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 899342c6dfad..1cbc372964f8 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> @@ -2954,54 +2954,6 @@ 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
> >> *
> >> @@ -3010,16 +2962,15 @@ 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);
> >> @@ -3028,44 +2979,40 @@ 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)
> >> + 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 650c45c896f0..ca8a0b7a5ac3 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> >> @@ -547,7 +547,7 @@ 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);
> >> }
> >>
> >> @@ -679,13 +679,10 @@ 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
> >> @@ -694,36 +691,19 @@ 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;
> >>
> > May I know why won't need the reservation_object_reserve_shared() here? Is
> > it because we only copy buffer from shadow parent bo instead of orignal bo?
>
> The scheduler and delayed free thread are disabled and we wait for the
> copy to finish before allowing any eviction to proceed.
>
> Adding the BO as shared fence to the BO could actually be harmful
> because TTM might already want to destroy it.
>

Thanks, patch is Reviewed-by: Huang Rui <ray.huang@amd.com>

> Regards,
> Christian.
>
> >
> > Thanks,
> > Ray
> >
> >> - 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 64337ff2ad63..7d3312d0da11 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);
> >>
> >> --
> >> 2.14.1
> >>
> >> _______________________________________________
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> >> amd-gfx@lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx