drm/amdgpu: reserve backup pages for bad page retirment

To ensure user has a constant of VRAM accessible in run-time, driver
reserves limit backup pages when init, and return ones when bad pages
retired, to keep no change of unused memory size.

v2: refine codes to calculate badpags threshold
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Dennis Li <Dennis.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -171,7 +171,7 @@ struct amdgpu_mgpu_info mgpu_info = {
 };
 int amdgpu_ras_enable = -1;
 uint amdgpu_ras_mask = 0xffffffff;
-int amdgpu_bad_page_threshold = -1;
+int amdgpu_bad_page_threshold = 100;
 
 /**
  * DOC: vramlimit (int)
@@ -805,7 +805,7 @@ module_param_named(reset_method, amdgpu_reset_method, int, 0444);
  * faulty pages by ECC exceed threshold value and leave it for user's further
  * check.
  */
-MODULE_PARM_DESC(bad_page_threshold, "Bad page threshold(-1 = auto(default value), 0 = disable bad page retirement)");
+MODULE_PARM_DESC(bad_page_threshold, "Bad page threshold(-1 = auto, 0 = disable bad page retirement, 100 = default value");
 module_param_named(bad_page_threshold, amdgpu_bad_page_threshold, int, 0444);
 
 MODULE_PARM_DESC(num_kcq, "number of kernel compute queue user want to setup (8 if set to greater than 8 or less than 0, only affect gfx 8+)");

drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c

@@ -1747,13 +1747,14 @@ static bool amdgpu_ras_check_bad_page(struct amdgpu_device *adev,
 	return ret;
 }
 
-static void amdgpu_ras_validate_threshold(struct amdgpu_device *adev,
-					uint32_t max_length)
+static uint32_t
+amdgpu_ras_calculate_badpags_threshold(struct amdgpu_device *adev)
 {
-	struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
 	int tmp_threshold = amdgpu_bad_page_threshold;
 	u64 val;
+	uint32_t max_length = 0;
 
+	max_length = amdgpu_ras_eeprom_get_record_max_length();
 	/*
 	 * Justification of value bad_page_cnt_threshold in ras structure
 	 *
@@ -1779,20 +1780,18 @@ static void amdgpu_ras_validate_threshold(struct amdgpu_device *adev,
 		tmp_threshold = max_length;
 
 	if (tmp_threshold == -1) {
-		val = adev->gmc.mc_vram_size;
+		val = adev->gmc.real_vram_size;
 		do_div(val, RAS_BAD_PAGE_RATE);
-		con->bad_page_cnt_threshold = min(lower_32_bits(val),
-						max_length);
-	} else {
-		con->bad_page_cnt_threshold = tmp_threshold;
+		tmp_threshold = min(lower_32_bits(val), max_length);
 	}
+
+	return tmp_threshold;
 }
 
 int amdgpu_ras_recovery_init(struct amdgpu_device *adev)
 {
 	struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
 	struct ras_err_handler_data **data;
-	uint32_t max_eeprom_records_len = 0;
 	bool exc_err_limit = false;
 	int ret;
 
@@ -1812,8 +1811,16 @@ int amdgpu_ras_recovery_init(struct amdgpu_device *adev)
 	atomic_set(&con->in_recovery, 0);
 	con->adev = adev;
 
-	max_eeprom_records_len = amdgpu_ras_eeprom_get_record_max_length();
-	amdgpu_ras_validate_threshold(adev, max_eeprom_records_len);
+	if (!con->bad_page_cnt_threshold) {
+		con->bad_page_cnt_threshold =
+			amdgpu_ras_calculate_badpags_threshold(adev);
+
+		ret = amdgpu_vram_mgr_reserve_backup_pages(
+			ttm_manager_type(&adev->mman.bdev, TTM_PL_VRAM),
+			con->bad_page_cnt_threshold);
+		if (ret)
+			goto out;
+	}
 
 	ret = amdgpu_ras_eeprom_init(&con->eeprom_control, &exc_err_limit);
 	/*

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h

@@ -48,6 +48,8 @@ struct amdgpu_vram_mgr {
 	spinlock_t lock;
 	struct list_head reservations_pending;
 	struct list_head reserved_pages;
+	struct list_head backup_pages;
+	uint32_t num_backup_pages;
 	atomic64_t usage;
 	atomic64_t vis_usage;
 };
@@ -123,6 +125,8 @@ uint64_t amdgpu_vram_mgr_usage(struct ttm_resource_manager *man);
 uint64_t amdgpu_vram_mgr_vis_usage(struct ttm_resource_manager *man);
 int amdgpu_vram_mgr_reserve_range(struct ttm_resource_manager *man,
 				  uint64_t start, uint64_t size);
+int amdgpu_vram_mgr_reserve_backup_pages(struct ttm_resource_manager *man,
+					 uint32_t num_pages);
 int amdgpu_vram_mgr_query_page_status(struct ttm_resource_manager *man,
 				      uint64_t start);
 

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c

@@ -28,6 +28,9 @@
 #include "amdgpu_atomfirmware.h"
 #include "atom.h"
 
+static int amdgpu_vram_mgr_free_backup_pages(struct amdgpu_vram_mgr *mgr,
+					     uint32_t num_pages);
+
 static inline struct amdgpu_vram_mgr *to_vram_mgr(struct ttm_resource_manager *man)
 {
 	return container_of(man, struct amdgpu_vram_mgr, manager);
@@ -186,6 +189,7 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev)
 	spin_lock_init(&mgr->lock);
 	INIT_LIST_HEAD(&mgr->reservations_pending);
 	INIT_LIST_HEAD(&mgr->reserved_pages);
+	INIT_LIST_HEAD(&mgr->backup_pages);
 
 	/* Add the two VRAM-related sysfs files */
 	ret = sysfs_create_files(&adev->dev->kobj, amdgpu_vram_mgr_attributes);
@@ -226,6 +230,11 @@ void amdgpu_vram_mgr_fini(struct amdgpu_device *adev)
 		drm_mm_remove_node(&rsv->mm_node);
 		kfree(rsv);
 	}
+
+	list_for_each_entry_safe(rsv, temp, &mgr->backup_pages, node) {
+		drm_mm_remove_node(&rsv->mm_node);
+		kfree(rsv);
+	}
 	drm_mm_takedown(&mgr->mm);
 	spin_unlock(&mgr->lock);
 
@@ -297,12 +306,14 @@ static void amdgpu_vram_mgr_do_reserve(struct ttm_resource_manager *man)
 			continue;
 
 		dev_dbg(adev->dev, "Reservation 0x%llx - %lld, Succeeded\n",
-			rsv->mm_node.start, rsv->mm_node.size);
+			rsv->mm_node.start << PAGE_SHIFT, rsv->mm_node.size);
 
 		vis_usage = amdgpu_vram_mgr_vis_size(adev, &rsv->mm_node);
 		atomic64_add(vis_usage, &mgr->vis_usage);
 		atomic64_add(rsv->mm_node.size << PAGE_SHIFT, &mgr->usage);
 		list_move(&rsv->node, &mgr->reserved_pages);
+
+		amdgpu_vram_mgr_free_backup_pages(mgr, rsv->mm_node.size);
 	}
 }
 
@@ -319,6 +330,7 @@ int amdgpu_vram_mgr_reserve_range(struct ttm_resource_manager *man,
 				  uint64_t start, uint64_t size)
 {
 	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
+	struct amdgpu_device *adev = to_amdgpu_device(mgr);
 	struct amdgpu_vram_reservation *rsv;
 
 	rsv = kzalloc(sizeof(*rsv), GFP_KERNEL);
@@ -329,14 +341,94 @@ int amdgpu_vram_mgr_reserve_range(struct ttm_resource_manager *man,
 	rsv->mm_node.start = start >> PAGE_SHIFT;
 	rsv->mm_node.size = size >> PAGE_SHIFT;
 
+	dev_dbg(adev->dev, "Pending Reservation: 0x%llx\n", start);
+
 	spin_lock(&mgr->lock);
-	list_add_tail(&mgr->reservations_pending, &rsv->node);
+	list_add_tail(&rsv->node, &mgr->reservations_pending);
 	amdgpu_vram_mgr_do_reserve(man);
 	spin_unlock(&mgr->lock);
 
 	return 0;
 }
 
+static int amdgpu_vram_mgr_free_backup_pages(struct amdgpu_vram_mgr *mgr,
+					     uint32_t num_pages)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(mgr);
+	struct amdgpu_vram_reservation *rsv;
+	uint32_t i;
+	uint64_t vis_usage = 0, total_usage = 0;
+
+	if (num_pages > mgr->num_backup_pages) {
+		dev_warn(adev->dev, "No enough backup pages\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_pages; i++) {
+		rsv = list_first_entry(&mgr->backup_pages,
+				       struct amdgpu_vram_reservation, node);
+		vis_usage += amdgpu_vram_mgr_vis_size(adev, &rsv->mm_node);
+		total_usage += (rsv->mm_node.size << PAGE_SHIFT);
+		drm_mm_remove_node(&rsv->mm_node);
+		list_del(&rsv->node);
+		kfree(rsv);
+		mgr->num_backup_pages--;
+	}
+
+	atomic64_sub(total_usage, &mgr->usage);
+	atomic64_sub(vis_usage, &mgr->vis_usage);
+
+	return 0;
+}
+
+int amdgpu_vram_mgr_reserve_backup_pages(struct ttm_resource_manager *man,
+					 uint32_t num_pages)
+{
+	struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
+	struct amdgpu_device *adev = to_amdgpu_device(mgr);
+	struct amdgpu_vram_reservation *rsv;
+	struct drm_mm *mm = &mgr->mm;
+	uint32_t i;
+	int ret = 0;
+	uint64_t vis_usage, total_usage;
+
+	for (i = 0; i < num_pages; i++) {
+		rsv = kzalloc(sizeof(*rsv), GFP_KERNEL);
+		if (!rsv) {
+			ret = -ENOMEM;
+			goto pro_end;
+		}
+
+		INIT_LIST_HEAD(&rsv->node);
+
+		ret = drm_mm_insert_node(mm, &rsv->mm_node, 1);
+		if (ret) {
+			dev_err(adev->dev, "failed to reserve backup page %d, ret 0x%x\n", i, ret);
+			kfree(rsv);
+			goto pro_end;
+		}
+
+		vis_usage = amdgpu_vram_mgr_vis_size(adev, &rsv->mm_node);
+		total_usage = (rsv->mm_node.size << PAGE_SHIFT);
+
+		spin_lock(&mgr->lock);
+		atomic64_add(vis_usage, &mgr->vis_usage);
+		atomic64_add(total_usage, &mgr->usage);
+		list_add_tail(&rsv->node, &mgr->backup_pages);
+		mgr->num_backup_pages++;
+		spin_unlock(&mgr->lock);
+	}
+
+pro_end:
+	if (ret) {
+		spin_lock(&mgr->lock);
+		amdgpu_vram_mgr_free_backup_pages(mgr, mgr->num_backup_pages);
+		spin_unlock(&mgr->lock);
+	}
+
+	return ret;
+}
+
 /**
  * amdgpu_vram_mgr_query_page_status - query the reservation status
  *