[PATCH 2/3] drm/amdkfd: skip invalid pages during migrations

[Felix Kuehling]

Am 2021-05-12 um 1:34 p.m. schrieb Alex Sierra:
> Invalid pages can be the result of pages that have been migrated
> already due to copy-on-write procedure or pages that were never
> migrated to VRAM in first place. This is not an issue anymore,
> as pranges now support mixed memory domains (CPU/GPU).
>
> Signed-off-by: Alex Sierra <alex.sierra at amd.com>

Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>


> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 36 +++++++++++-------------
>  1 file changed, 17 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
> index b298aa8dea4d..e1cc844b2f4e 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
> @@ -419,7 +419,6 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>  	size_t size;
>  	void *buf;
>  	int r = -ENOMEM;
> -	int retry = 0;
>  
>  	memset(&migrate, 0, sizeof(migrate));
>  	migrate.vma = vma;
> @@ -438,7 +437,6 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>  	migrate.dst = migrate.src + npages;
>  	scratch = (dma_addr_t *)(migrate.dst + npages);
>  
> -retry:
>  	r = migrate_vma_setup(&migrate);
>  	if (r) {
>  		pr_debug("failed %d prepare migrate svms 0x%p [0x%lx 0x%lx]\n",
> @@ -446,17 +444,9 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
>  		goto out_free;
>  	}
>  	if (migrate.cpages != npages) {
> -		pr_debug("collect 0x%lx/0x%llx pages, retry\n", migrate.cpages,
> +		pr_debug("Partial migration. 0x%lx/0x%llx pages can be migrated\n",
> +			 migrate.cpages,
>  			 npages);
> -		migrate_vma_finalize(&migrate);
> -		if (retry++ >= 3) {
> -			r = -ENOMEM;
> -			pr_debug("failed %d migrate svms 0x%p [0x%lx 0x%lx]\n",
> -				 r, prange->svms, prange->start, prange->last);
> -			goto out_free;
> -		}
> -
> -		goto retry;
>  	}
>  
>  	if (migrate.cpages) {
> @@ -547,9 +537,8 @@ static void svm_migrate_page_free(struct page *page)
>  static int
>  svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
>  			struct migrate_vma *migrate, struct dma_fence **mfence,
> -			dma_addr_t *scratch)
> +			dma_addr_t *scratch, uint64_t npages)
>  {
> -	uint64_t npages = migrate->cpages;
>  	struct device *dev = adev->dev;
>  	uint64_t *src;
>  	dma_addr_t *dst;
> @@ -566,15 +555,23 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
>  	src = (uint64_t *)(scratch + npages);
>  	dst = scratch;
>  
> -	for (i = 0, j = 0; i < npages; i++, j++, addr += PAGE_SIZE) {
> +	for (i = 0, j = 0; i < npages; i++, addr += PAGE_SIZE) {
>  		struct page *spage;
>  
>  		spage = migrate_pfn_to_page(migrate->src[i]);
>  		if (!spage) {
> -			pr_debug("failed get spage svms 0x%p [0x%lx 0x%lx]\n",
> +			pr_debug("invalid page. Could be in CPU already svms 0x%p [0x%lx 0x%lx]\n",
>  				 prange->svms, prange->start, prange->last);
> -			r = -ENOMEM;
> -			goto out_oom;
> +			if (j) {
> +				r = svm_migrate_copy_memory_gart(adev, dst + i - j,
> +								 src + i - j, j,
> +								 FROM_VRAM_TO_RAM,
> +								 mfence);
> +				if (r)
> +					goto out_oom;
> +				j = 0;
> +			}
> +			continue;
>  		}
>  		src[i] = svm_migrate_addr(adev, spage);
>  		if (i > 0 && src[i] != src[i - 1] + PAGE_SIZE) {
> @@ -607,6 +604,7 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
>  
>  		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));
>  		migrate->dst[i] |= MIGRATE_PFN_LOCKED;
> +		j++;
>  	}
>  
>  	r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
> @@ -664,7 +662,7 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
>  
>  	if (migrate.cpages) {
>  		r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
> -					    scratch);
> +					    scratch, npages);
>  		migrate_vma_pages(&migrate);
>  		svm_migrate_copy_done(adev, mfence);
>  		migrate_vma_finalize(&migrate);