1 files changed, 244 insertions, 6 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index d939925efa81..15cab9bda17f 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -28,7 +28,7 @@
 /*
  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  */
-
+#include <linux/swap.h>
 #include <linux/vmalloc.h>
 
 #include <drm/ttm/ttm_bo.h>
@@ -769,12 +769,10 @@ error_destroy_tt:
 	return ret;
 }
 
-static bool ttm_lru_walk_trylock(struct ttm_lru_walk *walk,
+static bool ttm_lru_walk_trylock(struct ttm_operation_ctx *ctx,
 				 struct ttm_buffer_object *bo,
 				 bool *needs_unlock)
 {
-	struct ttm_operation_ctx *ctx = walk->ctx;
-
 	*needs_unlock = false;
 
 	if (dma_resv_trylock(bo->base.resv)) {
@@ -865,7 +863,8 @@ s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
 	s64 lret;
 
 	spin_lock(&bdev->lru_lock);
-	ttm_resource_manager_for_each_res(man, &cursor, res) {
+	ttm_resource_cursor_init(&cursor, man);
+	ttm_resource_manager_for_each_res(&cursor, res) {
 		struct ttm_buffer_object *bo = res->bo;
 		bool bo_needs_unlock = false;
 		bool bo_locked = false;
@@ -876,7 +875,7 @@ s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
 		 * since if we do it the other way around, and the trylock fails,
 		 * we need to drop the lru lock to put the bo.
 		 */
-		if (ttm_lru_walk_trylock(walk, bo, &bo_needs_unlock))
+		if (ttm_lru_walk_trylock(walk->ctx, bo, &bo_needs_unlock))
 			bo_locked = true;
 		else if (!walk->ticket || walk->ctx->no_wait_gpu ||
 			 walk->trylock_only)
@@ -919,3 +918,242 @@ s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
 
 	return progress;
 }
+EXPORT_SYMBOL(ttm_lru_walk_for_evict);
+
+static void ttm_bo_lru_cursor_cleanup_bo(struct ttm_bo_lru_cursor *curs)
+{
+	struct ttm_buffer_object *bo = curs->bo;
+
+	if (bo) {
+		if (curs->needs_unlock)
+			dma_resv_unlock(bo->base.resv);
+		ttm_bo_put(bo);
+		curs->bo = NULL;
+	}
+}
+
+/**
+ * ttm_bo_lru_cursor_fini() - Stop using a struct ttm_bo_lru_cursor
+ * and clean up any iteration it was used for.
+ * @curs: The cursor.
+ */
+void ttm_bo_lru_cursor_fini(struct ttm_bo_lru_cursor *curs)
+{
+	spinlock_t *lru_lock = &curs->res_curs.man->bdev->lru_lock;
+
+	ttm_bo_lru_cursor_cleanup_bo(curs);
+	spin_lock(lru_lock);
+	ttm_resource_cursor_fini(&curs->res_curs);
+	spin_unlock(lru_lock);
+}
+EXPORT_SYMBOL(ttm_bo_lru_cursor_fini);
+
+/**
+ * ttm_bo_lru_cursor_init() - Initialize a struct ttm_bo_lru_cursor
+ * @curs: The ttm_bo_lru_cursor to initialize.
+ * @man: The ttm resource_manager whose LRU lists to iterate over.
+ * @ctx: The ttm_operation_ctx to govern the locking.
+ *
+ * Initialize a struct ttm_bo_lru_cursor. Currently only trylocking
+ * or prelocked buffer objects are available as detailed by
+ * @ctx::resv and @ctx::allow_res_evict. Ticketlocking is not
+ * supported.
+ *
+ * Return: Pointer to @curs. The function does not fail.
+ */
+struct ttm_bo_lru_cursor *
+ttm_bo_lru_cursor_init(struct ttm_bo_lru_cursor *curs,
+		       struct ttm_resource_manager *man,
+		       struct ttm_operation_ctx *ctx)
+{
+	memset(curs, 0, sizeof(*curs));
+	ttm_resource_cursor_init(&curs->res_curs, man);
+	curs->ctx = ctx;
+
+	return curs;
+}
+EXPORT_SYMBOL(ttm_bo_lru_cursor_init);
+
+static struct ttm_buffer_object *
+ttm_bo_from_res_reserved(struct ttm_resource *res, struct ttm_bo_lru_cursor *curs)
+{
+	struct ttm_buffer_object *bo = res->bo;
+
+	if (!ttm_lru_walk_trylock(curs->ctx, bo, &curs->needs_unlock))
+		return NULL;
+
+	if (!ttm_bo_get_unless_zero(bo)) {
+		if (curs->needs_unlock)
+			dma_resv_unlock(bo->base.resv);
+		return NULL;
+	}
+
+	curs->bo = bo;
+	return bo;
+}
+
+/**
+ * ttm_bo_lru_cursor_next() - Continue iterating a manager's LRU lists
+ * to find and lock buffer object.
+ * @curs: The cursor initialized using ttm_bo_lru_cursor_init() and
+ * ttm_bo_lru_cursor_first().
+ *
+ * Return: A pointer to a locked and reference-counted buffer object,
+ * or NULL if none could be found and looping should be terminated.
+ */
+struct ttm_buffer_object *ttm_bo_lru_cursor_next(struct ttm_bo_lru_cursor *curs)
+{
+	spinlock_t *lru_lock = &curs->res_curs.man->bdev->lru_lock;
+	struct ttm_resource *res = NULL;
+	struct ttm_buffer_object *bo;
+
+	ttm_bo_lru_cursor_cleanup_bo(curs);
+
+	spin_lock(lru_lock);
+	for (;;) {
+		res = ttm_resource_manager_next(&curs->res_curs);
+		if (!res)
+			break;
+
+		bo = ttm_bo_from_res_reserved(res, curs);
+		if (bo)
+			break;
+	}
+
+	spin_unlock(lru_lock);
+	return res ? bo : NULL;
+}
+EXPORT_SYMBOL(ttm_bo_lru_cursor_next);
+
+/**
+ * ttm_bo_lru_cursor_first() - Start iterating a manager's LRU lists
+ * to find and lock buffer object.
+ * @curs: The cursor initialized using ttm_bo_lru_cursor_init().
+ *
+ * Return: A pointer to a locked and reference-counted buffer object,
+ * or NULL if none could be found and looping should be terminated.
+ */
+struct ttm_buffer_object *ttm_bo_lru_cursor_first(struct ttm_bo_lru_cursor *curs)
+{
+	spinlock_t *lru_lock = &curs->res_curs.man->bdev->lru_lock;
+	struct ttm_buffer_object *bo;
+	struct ttm_resource *res;
+
+	spin_lock(lru_lock);
+	res = ttm_resource_manager_first(&curs->res_curs);
+	if (!res) {
+		spin_unlock(lru_lock);
+		return NULL;
+	}
+
+	bo = ttm_bo_from_res_reserved(res, curs);
+	spin_unlock(lru_lock);
+
+	return bo ? bo : ttm_bo_lru_cursor_next(curs);
+}
+EXPORT_SYMBOL(ttm_bo_lru_cursor_first);
+
+/**
+ * ttm_bo_shrink() - Helper to shrink a ttm buffer object.
+ * @ctx: The struct ttm_operation_ctx used for the shrinking operation.
+ * @bo: The buffer object.
+ * @flags: Flags governing the shrinking behaviour.
+ *
+ * The function uses the ttm_tt_back_up functionality to back up or
+ * purge a struct ttm_tt. If the bo is not in system, it's first
+ * moved there.
+ *
+ * Return: The number of pages shrunken or purged, or
+ * negative error code on failure.
+ */
+long ttm_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
+		   const struct ttm_bo_shrink_flags flags)
+{
+	static const struct ttm_place sys_placement_flags = {
+		.fpfn = 0,
+		.lpfn = 0,
+		.mem_type = TTM_PL_SYSTEM,
+		.flags = 0,
+	};
+	static struct ttm_placement sys_placement = {
+		.num_placement = 1,
+		.placement = &sys_placement_flags,
+	};
+	struct ttm_tt *tt = bo->ttm;
+	long lret;
+
+	dma_resv_assert_held(bo->base.resv);
+
+	if (flags.allow_move && bo->resource->mem_type != TTM_PL_SYSTEM) {
+		int ret = ttm_bo_validate(bo, &sys_placement, ctx);
+
+		/* Consider -ENOMEM and -ENOSPC non-fatal. */
+		if (ret) {
+			if (ret == -ENOMEM || ret == -ENOSPC)
+				ret = -EBUSY;
+			return ret;
+		}
+	}
+
+	ttm_bo_unmap_virtual(bo);
+	lret = ttm_bo_wait_ctx(bo, ctx);
+	if (lret < 0)
+		return lret;
+
+	if (bo->bulk_move) {
+		spin_lock(&bo->bdev->lru_lock);
+		ttm_resource_del_bulk_move(bo->resource, bo);
+		spin_unlock(&bo->bdev->lru_lock);
+	}
+
+	lret = ttm_tt_backup(bo->bdev, tt, (struct ttm_backup_flags)
+			     {.purge = flags.purge,
+			      .writeback = flags.writeback});
+
+	if (lret <= 0 && bo->bulk_move) {
+		spin_lock(&bo->bdev->lru_lock);
+		ttm_resource_add_bulk_move(bo->resource, bo);
+		spin_unlock(&bo->bdev->lru_lock);
+	}
+
+	if (lret < 0 && lret != -EINTR)
+		return -EBUSY;
+
+	return lret;
+}
+EXPORT_SYMBOL(ttm_bo_shrink);
+
+/**
+ * ttm_bo_shrink_suitable() - Whether a bo is suitable for shinking
+ * @ctx: The struct ttm_operation_ctx governing the shrinking.
+ * @bo: The candidate for shrinking.
+ *
+ * Check whether the object, given the information available to TTM,
+ * is suitable for shinking, This function can and should be used
+ * before attempting to shrink an object.
+ *
+ * Return: true if suitable. false if not.
+ */
+bool ttm_bo_shrink_suitable(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx)
+{
+	return bo->ttm && ttm_tt_is_populated(bo->ttm) && !bo->pin_count &&
+		(!ctx->no_wait_gpu ||
+		 dma_resv_test_signaled(bo->base.resv, DMA_RESV_USAGE_BOOKKEEP));
+}
+EXPORT_SYMBOL(ttm_bo_shrink_suitable);
+
+/**
+ * ttm_bo_shrink_avoid_wait() - Whether to avoid waiting for GPU
+ * during shrinking
+ *
+ * In some situations, like direct reclaim, waiting (in particular gpu waiting)
+ * should be avoided since it may stall a system that could otherwise make progress
+ * shrinking something else less time consuming.
+ *
+ * Return: true if gpu waiting should be avoided, false if not.
+ */
+bool ttm_bo_shrink_avoid_wait(void)
+{
+	return !current_is_kswapd();
+}
+EXPORT_SYMBOL(ttm_bo_shrink_avoid_wait);