Am 2022-03-14 um 10:50 schrieb Philip Yang:
Migrate vram to ram may fail to find the vma if process is exiting
and vma is removed, evict svm bo worker sets prange->svm_bo to NULL
and warn svm_bo ref count != 1 only if migrating vram to ram
successfully.
Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
---
drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 27 +++++++++++++++++++-----
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 20 ++++++++++--------
2 files changed, 33 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 7f689094be5a..c8aef2fe459b 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -638,6 +638,22 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
return r;
}
+/**
+ * svm_migrate_vma_to_ram - migrate range inside one vma from device to system
+ *
+ * @adev: amdgpu device to migrate from
+ * @prange: svm range structure
+ * @vma: vm_area_struct that range [start, end] belongs to
+ * @start: range start virtual address in pages
+ * @end: range end virtual address in pages
+ *
+ * Context: Process context, caller hold mmap read lock, svms lock, prange lock
+ *
+ * Return:
+ * 0 - success with all pages migrated
+ * negative values - indicate error
+ * positive values - partial migration, number of pages not migrated
+ */
static long
svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
struct vm_area_struct *vma, uint64_t start, uint64_t end)
@@ -709,8 +725,6 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
pdd = svm_range_get_pdd_by_adev(prange, adev);
if (pdd)
WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
-
- return upages;
}
return r ? r : upages;
}
@@ -759,13 +773,16 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
unsigned long next;
vma = find_vma(mm, addr);
- if (!vma || addr < vma->vm_start)
+ if (!vma || addr < vma->vm_start) {
+ pr_debug("failed to find vma for prange %p\n", prange);
+ r = -EFAULT;
break;
+ }
next = min(vma->vm_end, end);
r = svm_migrate_vma_to_ram(adev, prange, vma, addr, next);
if (r < 0) {
- pr_debug("failed %ld to migrate\n", r);
+ pr_debug("failed %ld to migrate prange %p\n", r, prange);
break;
} else {
upages += r;
@@ -773,7 +790,7 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
addr = next;
}
- if (!upages) {
+ if (r >= 0 && !upages) {
svm_range_vram_node_free(prange);
prange->actual_loc = 0;
}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 509d915cbe69..215943424c06 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -3155,6 +3155,7 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
struct svm_range_bo *svm_bo;
struct kfd_process *p;
struct mm_struct *mm;
+ int r = 0;
svm_bo = container_of(work, struct svm_range_bo, eviction_work);
if (!svm_bo_ref_unless_zero(svm_bo))
@@ -3170,7 +3171,7 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
mmap_read_lock(mm);
spin_lock(&svm_bo->list_lock);
- while (!list_empty(&svm_bo->range_list)) {
+ while (!list_empty(&svm_bo->range_list) && !r) {
struct svm_range *prange =
list_first_entry(&svm_bo->range_list,
struct svm_range, svm_bo_list);
@@ -3184,15 +3185,15 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
mutex_lock(&prange->migrate_mutex);
do {
- svm_migrate_vram_to_ram(prange,
+ r = svm_migrate_vram_to_ram(prange,
svm_bo->eviction_fence->mm);
- } while (prange->actual_loc && --retries);
- WARN(prange->actual_loc, "Migration failed during eviction");
-
- mutex_lock(&prange->lock);
- prange->svm_bo = NULL;
- mutex_unlock(&prange->lock);
+ } while (!r && prange->actual_loc && --retries);
I think it would still be good to have a WARN here for other cases than
process termination. Is there a way to distinguish the process
termination case from the error code? Maybe we could even avoid the
retry in this case.
Other than that, this patch is a good improvement on the error handling.
Regards,
Felix
+ if (!prange->actual_loc) {
+ mutex_lock(&prange->lock);
+ prange->svm_bo = NULL;
+ mutex_unlock(&prange->lock);
+ }
mutex_unlock(&prange->migrate_mutex);
spin_lock(&svm_bo->list_lock);
@@ -3201,10 +3202,11 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
mmap_read_unlock(mm);
dma_fence_signal(&svm_bo->eviction_fence->base);
+
/* This is the last reference to svm_bo, after svm_range_vram_node_free
* has been called in svm_migrate_vram_to_ram
*/
- WARN_ONCE(kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
+ WARN_ONCE(!r && kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
svm_range_bo_unref(svm_bo);
}
