Revert "drm/amdkfd: Use partial migrations in GPU page faults"

This reverts commit dc427a473e. The change prevents migrating the entire range to VRAM because retry fault restore_pages map the remaining system memory range to GPUs. It will work correctly to submit together with partial mapping to GPU patch later. Signed-off-by: Philip Yang <Philip.Yang@amd.com> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2026-04-18 03:23:53 -04:00 · 2023-10-23 16:08:34 -04:00
parent afaec204d2
commit 541c341d2e
4 changed files with 85 additions and 160 deletions
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -442,10 +442,10 @@ svm_migrate_vma_to_vram(struct kfd_node *node, struct svm_range *prange,
 		goto out_free;
 	}
 	if (cpages != npages)
-		pr_debug("partial migration, 0x%lx/0x%llx pages collected\n",
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
 			 cpages, npages);
 	else
-		pr_debug("0x%lx pages collected\n", cpages);
+		pr_debug("0x%lx pages migrated\n", cpages);

 	r = svm_migrate_copy_to_vram(node, prange, &migrate, &mfence, scratch, ttm_res_offset);
 	migrate_vma_pages(&migrate);
@@ -479,8 +479,6 @@ out:
 * svm_migrate_ram_to_vram - migrate svm range from system to device
 * @prange: range structure
 * @best_loc: the device to migrate to
- * @start_mgr: start page to migrate
- * @last_mgr: last page to migrate
 * @mm: the process mm structure
 * @trigger: reason of migration
 *
@@ -491,7 +489,6 @@ out:
 */
 static int
 svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
-			unsigned long start_mgr, unsigned long last_mgr,
 			struct mm_struct *mm, uint32_t trigger)
 {
 	unsigned long addr, start, end;
@@ -501,30 +498,23 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
 	unsigned long cpages = 0;
 	long r = 0;

-	if (!best_loc) {
-		pr_debug("svms 0x%p [0x%lx 0x%lx] migrate to sys ram\n",
-			prange->svms, start_mgr, last_mgr);
+	if (prange->actual_loc == best_loc) {
+		pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
+			 prange->svms, prange->start, prange->last, best_loc);
 		return 0;
 	}

-	if (start_mgr < prange->start || last_mgr > prange->last) {
-		pr_debug("range [0x%lx 0x%lx] out prange [0x%lx 0x%lx]\n",
-				 start_mgr, last_mgr, prange->start, prange->last);
-		return -EFAULT;
-	}
-
 	node = svm_range_get_node_by_id(prange, best_loc);
 	if (!node) {
 		pr_debug("failed to get kfd node by id 0x%x\n", best_loc);
 		return -ENODEV;
 	}

-	pr_debug("svms 0x%p [0x%lx 0x%lx] in [0x%lx 0x%lx] to gpu 0x%x\n",
-		prange->svms, start_mgr, last_mgr, prange->start, prange->last,
-		best_loc);
+	pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms,
+		 prange->start, prange->last, best_loc);

-	start = start_mgr << PAGE_SHIFT;
-	end = (last_mgr + 1) << PAGE_SHIFT;
+	start = prange->start << PAGE_SHIFT;
+	end = (prange->last + 1) << PAGE_SHIFT;

 	r = svm_range_vram_node_new(node, prange, true);
 	if (r) {
@@ -554,11 +544,8 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,

 	if (cpages) {
 		prange->actual_loc = best_loc;
-		prange->vram_pages = prange->vram_pages + cpages;
-	} else if (!prange->actual_loc) {
-		/* if no page migrated and all pages from prange are at
-		 * sys ram drop svm_bo got from svm_range_vram_node_new
-		 */
+		svm_range_dma_unmap(prange);
+	} else {
 		svm_range_vram_node_free(prange);
 	}

@@ -676,8 +663,9 @@ out_oom:
 * Context: Process context, caller hold mmap read lock, prange->migrate_mutex
 *
 * Return:
+ *   0 - success with all pages migrated
 *   negative values - indicate error
- *   positive values or zero - number of pages got migrated
+ *   positive values - partial migration, number of pages not migrated
 */
 static long
 svm_migrate_vma_to_ram(struct kfd_node *node, struct svm_range *prange,
@@ -688,7 +676,6 @@ svm_migrate_vma_to_ram(struct kfd_node *node, struct svm_range *prange,
 	uint64_t npages = (end - start) >> PAGE_SHIFT;
 	unsigned long upages = npages;
 	unsigned long cpages = 0;
-	unsigned long mpages = 0;
 	struct amdgpu_device *adev = node->adev;
 	struct kfd_process_device *pdd;
 	struct dma_fence *mfence = NULL;
@@ -738,10 +725,10 @@ svm_migrate_vma_to_ram(struct kfd_node *node, struct svm_range *prange,
 		goto out_free;
 	}
 	if (cpages != npages)
-		pr_debug("partial migration, 0x%lx/0x%llx pages collected\n",
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
 			 cpages, npages);
 	else
-		pr_debug("0x%lx pages collected\n", cpages);
+		pr_debug("0x%lx pages migrated\n", cpages);

 	r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
 				    scratch, npages);
@@ -764,21 +751,17 @@ out_free:
 	kvfree(buf);
 out:
 	if (!r && cpages) {
-		mpages = cpages - upages;
 		pdd = svm_range_get_pdd_by_node(prange, node);
 		if (pdd)
-			WRITE_ONCE(pdd->page_out, pdd->page_out + mpages);
+			WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
 	}
-
-	return r ? r : mpages;
+	return r ? r : upages;
 }

 /**
 * svm_migrate_vram_to_ram - migrate svm range from device to system
 * @prange: range structure
 * @mm: process mm, use current->mm if NULL
- * @start_mgr: start page need be migrated to sys ram
- * @last_mgr: last page need be migrated to sys ram
 * @trigger: reason of migration
 * @fault_page: is from vmf->page, svm_migrate_to_ram(), this is CPU page fault callback
 *
@@ -788,7 +771,6 @@ out:
 * 0 - OK, otherwise error code
 */
 int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
-			    unsigned long start_mgr, unsigned long last_mgr,
 			    uint32_t trigger, struct page *fault_page)
 {
 	struct kfd_node *node;
@@ -796,33 +778,26 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
 	unsigned long addr;
 	unsigned long start;
 	unsigned long end;
-	unsigned long mpages = 0;
+	unsigned long upages = 0;
 	long r = 0;

-	/* this pragne has no any vram page to migrate to sys ram */
 	if (!prange->actual_loc) {
 		pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
 			 prange->start, prange->last);
 		return 0;
 	}

-	if (start_mgr < prange->start || last_mgr > prange->last) {
-		pr_debug("range [0x%lx 0x%lx] out prange [0x%lx 0x%lx]\n",
-				 start_mgr, last_mgr, prange->start, prange->last);
-		return -EFAULT;
-	}
-
 	node = svm_range_get_node_by_id(prange, prange->actual_loc);
 	if (!node) {
 		pr_debug("failed to get kfd node by id 0x%x\n", prange->actual_loc);
 		return -ENODEV;
 	}
 	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] from gpu 0x%x to ram\n",
-		 prange->svms, prange, start_mgr, last_mgr,
+		 prange->svms, prange, prange->start, prange->last,
 		 prange->actual_loc);

-	start = start_mgr << PAGE_SHIFT;
-	end = (last_mgr + 1) << PAGE_SHIFT;
+	start = prange->start << PAGE_SHIFT;
+	end = (prange->last + 1) << PAGE_SHIFT;

 	for (addr = start; addr < end;) {
 		unsigned long next;
@@ -841,21 +816,14 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
 			pr_debug("failed %ld to migrate prange %p\n", r, prange);
 			break;
 		} else {
-			mpages += r;
+			upages += r;
 		}
 		addr = next;
 	}

-	if (r >= 0) {
-		prange->vram_pages -= mpages;
-
-		/* prange does not have vram page set its actual_loc to system
-		 * and drop its svm_bo ref
-		 */
-		if (prange->vram_pages == 0 && prange->ttm_res) {
-			prange->actual_loc = 0;
-			svm_range_vram_node_free(prange);
-		}
+	if (r >= 0 && !upages) {
+		svm_range_vram_node_free(prange);
+		prange->actual_loc = 0;
 	}

 	return r < 0 ? r : 0;
@@ -865,23 +833,17 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
 * svm_migrate_vram_to_vram - migrate svm range from device to device
 * @prange: range structure
 * @best_loc: the device to migrate to
- * @start: start page need be migrated to sys ram
- * @last: last page need be migrated to sys ram
 * @mm: process mm, use current->mm if NULL
 * @trigger: reason of migration
 *
 * Context: Process context, caller hold mmap read lock, svms lock, prange lock
 *
- * migrate all vram pages in prange to sys ram, then migrate
- * [start, last] pages from sys ram to gpu node best_loc.
- *
 * Return:
 * 0 - OK, otherwise error code
 */
 static int
 svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
-			unsigned long start, unsigned long last,
-			struct mm_struct *mm, uint32_t trigger)
+			 struct mm_struct *mm, uint32_t trigger)
 {
 	int r, retries = 3;

@@ -893,8 +855,7 @@ svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
 	pr_debug("from gpu 0x%x to gpu 0x%x\n", prange->actual_loc, best_loc);

 	do {
-		r = svm_migrate_vram_to_ram(prange, mm, prange->start, prange->last,
-								trigger, NULL);
+		r = svm_migrate_vram_to_ram(prange, mm, trigger, NULL);
 		if (r)
 			return r;
 	} while (prange->actual_loc && --retries);
@@ -902,21 +863,17 @@ svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
 	if (prange->actual_loc)
 		return -EDEADLK;

-	return svm_migrate_ram_to_vram(prange, best_loc, start, last, mm, trigger);
+	return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
 }

 int
 svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
-			unsigned long start, unsigned long last,
-			struct mm_struct *mm, uint32_t trigger)
+		    struct mm_struct *mm, uint32_t trigger)
 {
-	if  (!prange->actual_loc || prange->actual_loc == best_loc)
-		return svm_migrate_ram_to_vram(prange, best_loc, start, last,
-						mm, trigger);
-
+	if  (!prange->actual_loc)
+		return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
 	else
-		return svm_migrate_vram_to_vram(prange, best_loc, start, last,
-						mm, trigger);
+		return svm_migrate_vram_to_vram(prange, best_loc, mm, trigger);

 }

@@ -932,9 +889,10 @@ svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
 */
 static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
 {
-	unsigned long start, last, size;
 	unsigned long addr = vmf->address;
 	struct svm_range_bo *svm_bo;
+	enum svm_work_list_ops op;
+	struct svm_range *parent;
 	struct svm_range *prange;
 	struct kfd_process *p;
 	struct mm_struct *mm;
@@ -971,31 +929,51 @@ static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)

 	mutex_lock(&p->svms.lock);

-	prange = svm_range_from_addr(&p->svms, addr, NULL);
+	prange = svm_range_from_addr(&p->svms, addr, &parent);
 	if (!prange) {
 		pr_debug("failed get range svms 0x%p addr 0x%lx\n", &p->svms, addr);
 		r = -EFAULT;
 		goto out_unlock_svms;
 	}

-	mutex_lock(&prange->migrate_mutex);
+	mutex_lock(&parent->migrate_mutex);
+	if (prange != parent)
+		mutex_lock_nested(&prange->migrate_mutex, 1);

 	if (!prange->actual_loc)
 		goto out_unlock_prange;

-	/* Align migration range start and size to granularity size */
-	size = 1UL << prange->granularity;
-	start = max(ALIGN_DOWN(addr, size), prange->start);
-	last = min(ALIGN(addr + 1, size) - 1, prange->last);
+	svm_range_lock(parent);
+	if (prange != parent)
+		mutex_lock_nested(&prange->lock, 1);
+	r = svm_range_split_by_granularity(p, mm, addr, parent, prange);
+	if (prange != parent)
+		mutex_unlock(&prange->lock);
+	svm_range_unlock(parent);
+	if (r) {
+		pr_debug("failed %d to split range by granularity\n", r);
+		goto out_unlock_prange;
+	}

-	r = svm_migrate_vram_to_ram(prange, vmf->vma->vm_mm, start, last,
-						KFD_MIGRATE_TRIGGER_PAGEFAULT_CPU, vmf->page);
+	r = svm_migrate_vram_to_ram(prange, vmf->vma->vm_mm,
+				    KFD_MIGRATE_TRIGGER_PAGEFAULT_CPU,
+				    vmf->page);
 	if (r)
 		pr_debug("failed %d migrate svms 0x%p range 0x%p [0x%lx 0x%lx]\n",
-			r, prange->svms, prange, start, last);
+			 r, prange->svms, prange, prange->start, prange->last);
+
+	/* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
+	if (p->xnack_enabled && parent == prange)
+		op = SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP;
+	else
+		op = SVM_OP_UPDATE_RANGE_NOTIFIER;
+	svm_range_add_list_work(&p->svms, parent, mm, op);
+	schedule_deferred_list_work(&p->svms);

 out_unlock_prange:
-	mutex_unlock(&prange->migrate_mutex);
+	if (prange != parent)
+		mutex_unlock(&prange->migrate_mutex);
+	mutex_unlock(&parent->migrate_mutex);
 out_unlock_svms:
 	mutex_unlock(&p->svms.lock);
 out_unref_process: