On 2022-09-07 20:16, Philip Yang wrote:
Prefaulting potentially allocates system memory pages before a migration. This adds unnecessary overhead. Instead we can skip unallocated pages in the migration and just point migrate->dst to a 0-initialized VRAM page directly. Then the VRAM page will be inserted to the PTE. A subsequent CPU page fault will migrate the page back to system memory. Signed-off-by: Philip Yang <[email protected]>
The series is Reviewed-by: Felix Kuehling <[email protected]>
--- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 12 +++++------- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 22 ---------------------- drivers/gpu/drm/amd/amdkfd/kfd_svm.h | 2 -- 3 files changed, 5 insertions(+), 31 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c index 8562dd0eb4b6..f62c4561f0f4 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c @@ -322,12 +322,13 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange, for (i = j = 0; i < npages; i++) { 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)) { - 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]); src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE, DMA_TO_DEVICE); r = dma_mapping_error(dev, src[i]); @@ -522,9 +523,6 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc, pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms, prange->start, prange->last, best_loc);- /* FIXME: workaround for page locking bug with invalid pages */- svm_range_prefault(prange, mm, SVM_ADEV_PGMAP_OWNER(adev)); - start = prange->start << PAGE_SHIFT; end = (prange->last + 1) << PAGE_SHIFT;diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.cindex 11074cc8c333..cf5b4005534c 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -3181,28 +3181,6 @@ svm_range_best_prefetch_location(struct svm_range *prange) return best_loc; }-/* FIXME: This is a workaround for page locking bug when some pages are- * invalid during migration to VRAM - */ -void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm, - void *owner) -{ - struct hmm_range *hmm_range; - int r; - - if (prange->validated_once) - return; - - r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL, - prange->start << PAGE_SHIFT, - prange->npages, &hmm_range, - false, true, owner); - if (!r) { - amdgpu_hmm_range_get_pages_done(hmm_range); - prange->validated_once = true; - } -} - /* svm_range_trigger_migration - start page migration if prefetch loc changed * @mm: current process mm_struct * @prange: svm range structure diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h index cfac13ad06ef..012c53729516 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h @@ -181,8 +181,6 @@ void schedule_deferred_list_work(struct svm_range_list *svms); void svm_range_dma_unmap(struct device *dev, dma_addr_t *dma_addr, unsigned long offset, unsigned long npages); void svm_range_free_dma_mappings(struct svm_range *prange); -void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm, - void *owner); int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges, uint64_t *svm_priv_data_size); int kfd_criu_checkpoint_svm(struct kfd_process *p,
