[AMD Official Use Only - AMD Internal Distribution Only]
From: Chen, Xiaogang <xiaogang.c...@amd.com> Sent: Monday, January 6, 2025 11:27 PM To: Deng, Emily <emily.d...@amd.com>; amd-gfx@lists.freedesktop.org Subject: Re: [PATCH] drm/amdkfd: Fix partial migrate issue On 1/2/2025 6:06 PM, Emily Deng wrote: For partial migrate from ram to vram, the migrate->cpages is not equal to migrate->npages, should use migrate->npages to check all needed migrate pages which could be copied or not. And only need to set those pages could be migrated to migrate->dst[i], or the migrate_vma_pages will migrate the wrong pages based on the migrate->dst[i]. Signed-off-by: Emily Deng <emily.d...@amd.com><mailto:emily.d...@amd.com> --- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c index 4b275937d05e..5c96c2d425e3 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c @@ -278,7 +278,7 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, struct migrate_vma *migrate, struct dma_fence **mfence, dma_addr_t *scratch, uint64_t ttm_res_offset) { - uint64_t npages = migrate->cpages; + uint64_t npages = migrate->npages; I agree this part. struct amdgpu_device *adev = node->adev; struct device *dev = adev->dev; struct amdgpu_res_cursor cursor; @@ -299,9 +299,6 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, struct page *spage; dst[i] = cursor.start + (j << PAGE_SHIFT); - migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]); - svm_migrate_get_vram_page(prange, migrate->dst[i]); - migrate->dst[i] = migrate_pfn(migrate->dst[i]); spage = migrate_pfn_to_page(migrate->src[i]); if (spage && !is_zone_device_page(spage)) { @@ -345,6 +342,9 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, } else { j++; } + migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]); + svm_migrate_get_vram_page(prange, migrate->dst[i]); + migrate->dst[i] = migrate_pfn(migrate->dst[i]); I think what current code misses here is that migrate->dst[i] should match migrate->src[i]: migrate->dst[i](vram page) got set for page that will be migrated from system ram, otherwise migrate->dst[i] should be zero. Your change makes migrates->dst[i] not set though its page has been migrated by svm_migrate_copy_memory_gart for the case that cpages != npages, because you set migrate->dst[i] at end of loop and use 'continue' after migration. The page migration happens at svm_migrate_copy_memory_gart, not migrate_vma_pages that migrates struct page meta-data from source struct page to destination struct page and has mmu notification. Regards Xiaogang The migrate->dst[i] default value is 0. The purpose of the change is to match the migrate->dst[i] and migrate->src[i]. And for svm_migrate_copy_to_vram, it only will call svm_migrate_copy_memory_gart to copy those pages which need to be migrated, for those don’t need migrate pages, it won’t call svm_migrate_copy_memory_gart. } r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j,
