Am 13.09.22 um 22:05 schrieb Philip Yang:
Free page table BO from vm resv unlocked context generate below
warnings.

Add a pt_free_work in vm to free page table BO from vm->pt_freed list.
pass vm resv unlock status from page table update caller, and add vm_bo
entry to vm->pt_freed list and schedule the pt_free_work if calling with
vm resv unlocked.

WARNING: CPU: 12 PID: 3238 at
drivers/gpu/drm/ttm/ttm_bo.c:106 ttm_bo_set_bulk_move+0xa1/0xc0
Call Trace:
  amdgpu_vm_pt_free+0x42/0xd0 [amdgpu]
  amdgpu_vm_pt_free_dfs+0xb3/0xf0 [amdgpu]
  amdgpu_vm_ptes_update+0x52d/0x850 [amdgpu]
  amdgpu_vm_update_range+0x2a6/0x640 [amdgpu]
  svm_range_unmap_from_gpus+0x110/0x300 [amdgpu]
  svm_range_cpu_invalidate_pagetables+0x535/0x600 [amdgpu]
  __mmu_notifier_invalidate_range_start+0x1cd/0x230
  unmap_vmas+0x9d/0x140
  unmap_region+0xa8/0x110

Signed-off-by: Philip Yang <philip.y...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c    |  4 ++
  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h    |  6 +++
  drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 47 ++++++++++++++++++++---
  3 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 59cac347baa3..27e6155053b6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2022,6 +2022,9 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct 
amdgpu_vm *vm)
        spin_lock_init(&vm->invalidated_lock);
        INIT_LIST_HEAD(&vm->freed);
        INIT_LIST_HEAD(&vm->done);
+       INIT_LIST_HEAD(&vm->pt_freed);
+       INIT_WORK(&vm->pt_free_work, amdgpu_vm_pt_free_work);
+       spin_lock_init(&vm->pt_free_lock);
/* create scheduler entities for page table updates */
        r = drm_sched_entity_init(&vm->immediate, DRM_SCHED_PRIORITY_NORMAL,
@@ -2244,6 +2247,7 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct 
amdgpu_vm *vm)
                amdgpu_vm_free_mapping(adev, vm, mapping, NULL);
        }
+ cancel_work_sync(&vm->pt_free_work);

We should probably not cancel the work here, but rather just wait for it to finish.

        amdgpu_vm_pt_free_root(adev, vm);
        amdgpu_bo_unreserve(root);
        amdgpu_bo_unref(&root);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 9ecb7f663e19..b77fe838c327 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -276,6 +276,11 @@ struct amdgpu_vm {
        /* BOs which are invalidated, has been updated in the PTs */
        struct list_head        done;
+ /* PT BOs scheduled to free and fill with zero if vm_resv is not hold */
+       struct list_head        pt_freed;
+       struct work_struct      pt_free_work;
+       spinlock_t              pt_free_lock;
+
        /* contains the page directory */
        struct amdgpu_vm_bo_base     root;
        struct dma_fence        *last_update;
@@ -471,6 +476,7 @@ int amdgpu_vm_pde_update(struct amdgpu_vm_update_params 
*params,
  int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params *params,
                          uint64_t start, uint64_t end,
                          uint64_t dst, uint64_t flags);
+void amdgpu_vm_pt_free_work(struct work_struct *work);
#if defined(CONFIG_DEBUG_FS)
  void amdgpu_debugfs_vm_bo_info(struct amdgpu_vm *vm, struct seq_file *m);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
index 88de9f0d4728..c6f91731ecfb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -624,12 +624,22 @@ static int amdgpu_vm_pt_alloc(struct amdgpu_device *adev,
   *
   * @entry: PDE to free
   */
-static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry)
+static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry, bool unlocked)
  {
        struct amdgpu_bo *shadow;
if (!entry->bo)
                return;
+
+       if (unlocked) {
+               spin_lock(&entry->vm->pt_free_lock);
+               list_move(&entry->vm_status, &entry->vm->pt_freed);
+               spin_unlock(&entry->vm->pt_free_lock);
+
+               schedule_work(&entry->vm->pt_free_work);
+               return;
+       }
+

I strongly prefer to handle this in amdgpu_vm_pt_free_dfs() or even the caller of this instead and keep this here the low level free function.

        shadow = amdgpu_bo_shadowed(entry->bo);
        if (shadow) {
                ttm_bo_set_bulk_move(&shadow->tbo, NULL);
@@ -641,6 +651,29 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base 
*entry)
        amdgpu_bo_unref(&entry->bo);
  }
+void amdgpu_vm_pt_free_work(struct work_struct *work)

I think we could make this one here static if we introduce a amdgpu_vm_pt_init()/amdgpu_vm_pt_fini() function. But not a must have.

Christian.

+{
+       struct amdgpu_vm_bo_base *entry, *next;
+       struct amdgpu_vm *vm;
+       struct amdgpu_bo *root;
+       LIST_HEAD(pt_freed);
+
+       vm = container_of(work, struct amdgpu_vm, pt_free_work);
+
+       spin_lock(&vm->pt_free_lock);
+       list_splice_init(&vm->pt_freed, &pt_freed);
+       spin_unlock(&vm->pt_free_lock);
+
+       root = amdgpu_bo_ref(vm->root.bo);
+       amdgpu_bo_reserve(root, true);
+
+       list_for_each_entry_safe(entry, next, &pt_freed, vm_status)
+               amdgpu_vm_pt_free(entry, false);
+
+       amdgpu_bo_unreserve(root);
+       amdgpu_bo_unref(&root);
+}
+
  /**
   * amdgpu_vm_pt_free_dfs - free PD/PT levels
   *
@@ -652,16 +685,17 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base 
*entry)
   */
  static void amdgpu_vm_pt_free_dfs(struct amdgpu_device *adev,
                                  struct amdgpu_vm *vm,
-                                 struct amdgpu_vm_pt_cursor *start)
+                                 struct amdgpu_vm_pt_cursor *start,
+                                 bool unlocked)
  {
        struct amdgpu_vm_pt_cursor cursor;
        struct amdgpu_vm_bo_base *entry;
for_each_amdgpu_vm_pt_dfs_safe(adev, vm, start, cursor, entry)
-               amdgpu_vm_pt_free(entry);
+               amdgpu_vm_pt_free(entry, unlocked);
if (start)
-               amdgpu_vm_pt_free(start->entry);
+               amdgpu_vm_pt_free(start->entry, unlocked);
  }
/**
@@ -673,7 +707,7 @@ static void amdgpu_vm_pt_free_dfs(struct amdgpu_device 
*adev,
   */
  void amdgpu_vm_pt_free_root(struct amdgpu_device *adev, struct amdgpu_vm *vm)
  {
-       amdgpu_vm_pt_free_dfs(adev, vm, NULL);
+       amdgpu_vm_pt_free_dfs(adev, vm, NULL, false);
  }
/**
@@ -966,7 +1000,8 @@ int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params 
*params,
                                if (cursor.entry->bo) {
                                        params->table_freed = true;
                                        amdgpu_vm_pt_free_dfs(adev, params->vm,
-                                                             &cursor);
+                                                             &cursor,
+                                                             params->unlocked);
                                }
                                amdgpu_vm_pt_next(adev, &cursor);
                        }

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