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 <Philip.Yang@xxxxxxx>
---
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.c
index 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,
--
2.35.1
