Am 2022-06-03 um 09:59 schrieb Philip Yang:
Migration range from system memory to VRAM, if system page can not be
locked or unmapped, we do partial migration and leave some pages in
system memory. Several bugs found to copy pages and update GPU mapping
for this situation:
1. copy to vram should use migrate->npage which is total pages of range
as npages, not migrate->cpages which is number of pages can be migrated.
2. After partial copy, set VRAM res cursor as j + 1, j is number of
system pages copied plus 1 page to skip copy.
3. copy to ram, should collect all continuous VRAM pages and copy
together.
4. Call amdgpu_vm_update_range, should pass in offset as bytes, not
as number of pages.
Thanks for catching all these. It's unfortunate that partial migrations
are currently so hard to trigger deliberately, which makes this code
path hard to test. Basically currently it is only used when page locking
fails due to race conditions.
Xiaogang is working on a change to use partial migration when migrating
large ranges in GPU page faults. Heads up, Xiaogang, you need this
patch. And once your changes are ready it should become possible to
write a KFDTest that checks data integrity with partial migrations.
One comment inline.
Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
---
drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 6 +++---
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 +-
2 files 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 43cd47723946..d03135a1f7e6 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -296,7 +296,7 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
struct migrate_vma *migrate, struct dma_fence **mfence,
dma_addr_t *scratch)
{
- uint64_t npages = migrate->cpages;
+ uint64_t npages = migrate->npages;
struct device *dev = adev->dev;
struct amdgpu_res_cursor cursor;
dma_addr_t *src;
@@ -344,7 +344,7 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
mfence);
if (r)
goto out_free_vram_pages;
- amdgpu_res_next(&cursor, j << PAGE_SHIFT);
+ amdgpu_res_next(&cursor, (j + 1) << PAGE_SHIFT);
j = 0;
} else {
amdgpu_res_next(&cursor, PAGE_SIZE);
@@ -590,7 +590,7 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
continue;
}
src[i] = svm_migrate_addr(adev, spage);
- if (i > 0 && src[i] != src[i - 1] + PAGE_SIZE) {
+ if (i > 0 && src[i] != src[i - 1] + PAGE_SIZE && j) {
I think the i > 0 condition is redundant now. You could just replace i >
0 with j > 0.
With that fixed, the patch is
Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
r = svm_migrate_copy_memory_gart(adev, dst + i - j,
src + i - j, j,
FROM_VRAM_TO_RAM,
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 2ba3de0fb8aa..d6fc00d51c8c 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1295,7 +1295,7 @@ svm_range_map_to_gpu(struct kfd_process_device *pdd, struct svm_range *prange,
r = amdgpu_vm_update_range(adev, vm, false, false, flush_tlb, NULL,
last_start, prange->start + i,
pte_flags,
- last_start - prange->start,
+ (last_start - prange->start) << PAGE_SHIFT,
bo_adev ? bo_adev->vm_manager.vram_base_offset : 0,
NULL, dma_addr, &vm->last_update);
