On 2024-02-23 08:42, Shashank Sharma
wrote:
This patch:
- adds a new list in amdgou_vm to hold the VM PT entries being freed
- waits for the TLB flush using the vm->tlb_flush_fence
- actually frees the PT BOs
V2: rebase
V3: Do not attach the tlb_fence to the entries, rather add the entries
to a list and delay their freeing (Christian)
Cc: Christian König <Christian.Koenig@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Felix Kuehling <felix.kuehling@xxxxxxx>
Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx>
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 6 +++
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 6 +++
drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 51 ++++++++++++++++++++---
3 files changed, 58 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 67c690044b97..eebb73f2c2ef 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -939,6 +939,10 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,
/* Makes sure no PD/PT is freed before the flush */
dma_resv_add_fence(vm->root.bo->tbo.base.resv, *fence,
DMA_RESV_USAGE_BOOKKEEP);
+
+ mutex_lock(&vm->tlb_fence_lock);
+ vm->tlb_fence_last = *fence;
+ mutex_unlock(&vm->tlb_fence_lock);
}
amdgpu_res_first(pages_addr ? NULL : res, offset,
@@ -2212,6 +2216,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
INIT_LIST_HEAD(&vm->freed);
INIT_LIST_HEAD(&vm->done);
INIT_LIST_HEAD(&vm->pt_freed);
+ INIT_LIST_HEAD(&vm->tlb_flush_waitlist);
INIT_WORK(&vm->pt_free_work, amdgpu_vm_pt_free_work);
INIT_KFIFO(vm->faults);
@@ -2244,6 +2249,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
vm->last_unlocked = dma_fence_get_stub();
vm->generation = 0;
+ mutex_init(&vm->tlb_fence_lock);
mutex_init(&vm->eviction_lock);
vm->evicting = false;
vm->tlb_fence_context = dma_fence_context_alloc(1);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 8e6fd25d07b7..77f10ed80973 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -334,6 +334,10 @@ struct amdgpu_vm {
uint64_t *tlb_seq_cpu_addr;
uint64_t tlb_fence_context;
+ struct mutex tlb_fence_lock;
+ struct dma_fence *tlb_fence_last;
+ struct list_head tlb_flush_waitlist;
+
atomic64_t kfd_last_flushed_seq;
/* How many times we had to re-generate the page tables */
@@ -379,6 +383,8 @@ struct amdgpu_vm {
/* cached fault info */
struct amdgpu_vm_fault_info fault_info;
+
+ int count_bos;
};
struct amdgpu_vm_manager {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
index 95dc0afdaffb..57ea95c5c085 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -643,13 +643,13 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry)
if (!entry->bo)
return;
- entry->bo->vm_bo = NULL;
shadow = amdgpu_bo_shadowed(entry->bo);
if (shadow) {
ttm_bo_set_bulk_move(&shadow->tbo, NULL);
amdgpu_bo_unref(&shadow);
}
ttm_bo_set_bulk_move(&entry->bo->tbo, NULL);
+ entry->bo->vm_bo = NULL;
spin_lock(&entry->vm->status_lock);
list_del(&entry->vm_status);
@@ -657,6 +657,38 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry)
amdgpu_bo_unref(&entry->bo);
}
+static void amdgpu_vm_pt_flush_waitlist(struct amdgpu_vm *vm)
+{
+ struct amdgpu_vm_bo_base *entry, *next;
+ LIST_HEAD(tlb_flush_waitlist);
+
+ if (!vm || list_empty(&vm->tlb_flush_waitlist))
+ return;
+
+ /* Wait for pending TLB flush before freeing PT BOs */
+ mutex_lock(&vm->tlb_fence_lock);
+ if (vm->tlb_fence_last && !dma_fence_is_signaled(vm->tlb_fence_last)) {
+ if (dma_fence_wait_timeout(vm->tlb_fence_last, false,
+ MAX_SCHEDULE_TIMEOUT) <= 0) {
+ DRM_ERROR("Timedout waiting for TLB flush, not freeing PT BOs\n");
+ mutex_unlock(&vm->tlb_fence_lock);
+ return;
+ }
+
+ vm->tlb_fence_last = NULL;
+ }
+
+ /* Save the waitlist locally and reset the flushlist */
+ list_splice_init(&vm->tlb_flush_waitlist, &tlb_flush_waitlist);
+ mutex_unlock(&vm->tlb_fence_lock);
+
+ /* Now free the entries */
+ list_for_each_entry_safe(entry, next, &tlb_flush_waitlist, vm_status) {
+ if (entry)
+ amdgpu_vm_pt_free(entry);
+ }
+}
+
void amdgpu_vm_pt_free_work(struct work_struct *work)
{
struct amdgpu_vm_bo_base *entry, *next;
@@ -673,7 +705,7 @@ void amdgpu_vm_pt_free_work(struct work_struct *work)
amdgpu_bo_reserve(vm->root.bo, true);
list_for_each_entry_safe(entry, next, &pt_freed, vm_status)
- amdgpu_vm_pt_free(entry);
+ list_move(&entry->vm_status, &vm->tlb_flush_waitlist);
amdgpu_bo_unreserve(vm->root.bo);
}
@@ -708,11 +740,17 @@ static void amdgpu_vm_pt_free_dfs(struct amdgpu_device *adev,
return;
}
- for_each_amdgpu_vm_pt_dfs_safe(adev, vm, start, cursor, entry)
- amdgpu_vm_pt_free(entry);
+ mutex_lock(&vm->tlb_fence_lock);
+
+ for_each_amdgpu_vm_pt_dfs_safe(adev, vm, start, cursor, entry) {
+ if (entry)
+ list_add(&entry->vm_status, &vm->tlb_flush_waitlist);
+ }
if (start)
- amdgpu_vm_pt_free(start->entry);
+ list_add(&start->entry->vm_status, &vm->tlb_flush_waitlist);
+
+ mutex_unlock(&vm->tlb_fence_lock);
Because pt bo attached with tlb flush fence already, so amdgpu_vm_pt_free will not free the bo, the tlb flush work will signal the tlb fence, and then the pt bo will be freed.
To add freed pt bo to vm->tlb_flush_waitlist, and then wait for tlb flush fence at end of updating mapping is unnecessary, this patch seems redundant.
Regards,
Philip
}
/**
@@ -725,6 +763,7 @@ 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, false);
+ amdgpu_vm_pt_flush_waitlist(vm);
}
/**
@@ -1070,6 +1109,8 @@ int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params *params,
}
}
+ /* Actually free the buffers now */
+ amdgpu_vm_pt_flush_waitlist(params->vm);
return 0;
}
