drm/ttm: move swapout logic around v3

Move the iteration of the global lru into the new function
ttm_global_swapout() and use that instead in drivers.

v2: consistently return int
v3: fix build fail
Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/424008/

drivers/gpu/drm/ttm/ttm_bo.c

@@ -1193,56 +1193,35 @@ int ttm_bo_wait(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(ttm_bo_wait);
 
-/*
- * A buffer object shrink method that tries to swap out the first
- * buffer object on the bo_global::swap_lru list.
- */
-int ttm_bo_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
+int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
+		   gfp_t gfp_flags)
 {
 	struct ttm_global *glob = &ttm_glob;
-	struct ttm_buffer_object *bo;
-	int ret = -EBUSY;
 	bool locked;
-	unsigned i;
-
-	spin_lock(&glob->lru_lock);
-	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
-		list_for_each_entry(bo, &glob->swap_lru[i], swap) {
-			if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
-							    NULL))
-				continue;
-
-			if (!ttm_bo_get_unless_zero(bo)) {
-				if (locked)
-					dma_resv_unlock(bo->base.resv);
-				continue;
-			}
+	int ret;
 
-			ret = 0;
-			break;
-		}
-		if (!ret)
-			break;
-	}
+	if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked, NULL))
+		return -EBUSY;
 
-	if (ret) {
-		spin_unlock(&glob->lru_lock);
-		return ret;
+	if (!ttm_bo_get_unless_zero(bo)) {
+		if (locked)
+			dma_resv_unlock(bo->base.resv);
+		return -EBUSY;
 	}
 
 	if (bo->deleted) {
-		ret = ttm_bo_cleanup_refs(bo, false, false, locked);
+		ttm_bo_cleanup_refs(bo, false, false, locked);
 		ttm_bo_put(bo);
-		return ret;
+		return 0;
 	}
 
 	ttm_bo_del_from_lru(bo);
+	/* TODO: Cleanup the locking */
 	spin_unlock(&glob->lru_lock);
 
-	/**
+	/*
 	 * Move to system cached
 	 */
-
 	if (bo->mem.mem_type != TTM_PL_SYSTEM) {
 		struct ttm_operation_ctx ctx = { false, false };
 		struct ttm_resource evict_mem;
@@ -1262,29 +1241,26 @@ int ttm_bo_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
 		}
 	}
 
-	/**
+	/*
 	 * Make sure BO is idle.
 	 */
-
 	ret = ttm_bo_wait(bo, false, false);
 	if (unlikely(ret != 0))
 		goto out;
 
 	ttm_bo_unmap_virtual(bo);
 
-	/**
+	/*
 	 * Swap out. Buffer will be swapped in again as soon as
 	 * anyone tries to access a ttm page.
 	 */
-
 	if (bo->bdev->funcs->swap_notify)
 		bo->bdev->funcs->swap_notify(bo);
 
 	ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
 out:
 
-	/**
-	 *
+	/*
 	 * Unreserve without putting on LRU to avoid swapping out an
 	 * already swapped buffer.
 	 */
@@ -1293,7 +1269,6 @@ int ttm_bo_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
 	ttm_bo_put(bo);
 	return ret;
 }
-EXPORT_SYMBOL(ttm_bo_swapout);
 
 void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)
 {

drivers/gpu/drm/ttm/ttm_device.c

@@ -102,6 +102,35 @@ static int ttm_global_init(void)
 	return ret;
 }
 
+/**
+ * A buffer object shrink method that tries to swap out the first
+ * buffer object on the global::swap_lru list.
+ */
+int ttm_global_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
+{
+	struct ttm_global *glob = &ttm_glob;
+	struct ttm_buffer_object *bo;
+	unsigned i;
+	int ret;
+
+	spin_lock(&glob->lru_lock);
+	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
+		list_for_each_entry(bo, &glob->swap_lru[i], swap) {
+			uint32_t num_pages = bo->ttm->num_pages;
+
+			ret = ttm_bo_swapout(bo, ctx, gfp_flags);
+			/* ttm_bo_swapout has dropped the lru_lock */
+			if (!ret)
+				return num_pages;
+			if (ret != -EBUSY)
+				return ret;
+		}
+	}
+	spin_unlock(&glob->lru_lock);
+	return 0;
+}
+EXPORT_SYMBOL(ttm_global_swapout);
+
 static void ttm_init_sysman(struct ttm_device *bdev)
 {
 	struct ttm_resource_manager *man = &bdev->sysman;

drivers/gpu/drm/ttm/ttm_tt.c

@@ -369,7 +369,7 @@ static unsigned long ttm_tt_shrinker_scan(struct shrinker *shrink,
 	};
 	int ret;
 
-	ret = ttm_bo_swapout(&ctx, GFP_NOFS);
+	ret = ttm_global_swapout(&ctx, GFP_NOFS);
 	return ret < 0 ? SHRINK_EMPTY : ret;
 }
 

drivers/gpu/drm/vmwgfx/ttm_memory.c

@@ -38,6 +38,7 @@
 
 #include <drm/drm_device.h>
 #include <drm/drm_file.h>
+#include <drm/ttm/ttm_device.h>
 
 #include "ttm_memory.h"
 
@@ -277,7 +278,7 @@ static void ttm_shrink(struct ttm_mem_global *glob, bool from_wq,
 
 	while (ttm_zones_above_swap_target(glob, from_wq, extra)) {
 		spin_unlock(&glob->lock);
-		ret = ttm_bo_swapout(ctx, GFP_KERNEL);
+		ret = ttm_global_swapout(ctx, GFP_KERNEL);
 		spin_lock(&glob->lock);
 		if (unlikely(ret < 0))
 			break;

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -1371,7 +1371,7 @@ static int vmw_pm_freeze(struct device *kdev)
 	vmw_execbuf_release_pinned_bo(dev_priv);
 	vmw_resource_evict_all(dev_priv);
 	vmw_release_device_early(dev_priv);
-	while (ttm_bo_swapout(&ctx, GFP_KERNEL) > 0);
+	while (ttm_global_swapout(&ctx, GFP_KERNEL) > 0);
 	if (dev_priv->enable_fb)
 		vmw_fifo_resource_dec(dev_priv);
 	if (atomic_read(&dev_priv->num_fifo_resources) != 0) {

include/drm/ttm/ttm_bo_api.h

@@ -560,7 +560,8 @@ ssize_t ttm_bo_io(struct ttm_device *bdev, struct file *filp,
 		  const char __user *wbuf, char __user *rbuf,
 		  size_t count, loff_t *f_pos, bool write);
 
-int ttm_bo_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags);
+int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
+		   gfp_t gfp_flags);
 
 /**
  * ttm_bo_uses_embedded_gem_object - check if the given bo uses the

include/drm/ttm/ttm_device.h

@@ -297,6 +297,8 @@ struct ttm_device {
 	struct delayed_work wq;
 };
 
+int ttm_global_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags);
+
 static inline struct ttm_resource_manager *
 ttm_manager_type(struct ttm_device *bdev, int mem_type)
 {