[PATCH 08/10] vmwgfx: Restrict number of GMR pages to device limit

[Thomas Hellstrom <thellstrom@vmware.com>]

When GMR2 is available, make sure we restrict the number of used GMR pages
to the limit indicated by the device.
This is done by failing a GMRID allocation if the total number of GMR pages
exceeds the limit.
As a result TTM will then start evicting buffers in GMR memory on a
LRU basis until the allocation succeeds.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c           |   12 ++++++
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.h           |    2 +
 drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c |   46 +++++++++++++++++++------
 3 files changed, 49 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 0f3648e..4ac7039 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -326,6 +326,12 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 		dev_priv->max_gmr_ids =
 			vmw_read(dev_priv, SVGA_REG_GMR_MAX_IDS);
 	}
+	if (dev_priv->capabilities & SVGA_CAP_GMR2) {
+		dev_priv->max_gmr_pages =
+			vmw_read(dev_priv, SVGA_REG_GMRS_MAX_PAGES);
+		dev_priv->memory_size =
+			vmw_read(dev_priv, SVGA_REG_MEMORY_SIZE);
+	}
 
 	dev_priv->vram_size = vmw_read(dev_priv, SVGA_REG_VRAM_SIZE);
 	dev_priv->mmio_size = vmw_read(dev_priv, SVGA_REG_MEM_SIZE);
@@ -342,6 +348,12 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 		DRM_INFO("Max GMR descriptors is %u\n",
 			 (unsigned)dev_priv->max_gmr_descriptors);
 	}
+	if (dev_priv->capabilities & SVGA_CAP_GMR2) {
+		DRM_INFO("Max number of GMR pages is %u\n",
+			 (unsigned)dev_priv->max_gmr_pages);
+		DRM_INFO("Max dedicated hypervisor graphics memory is %u\n",
+			 (unsigned)dev_priv->memory_size);
+	}
 	DRM_INFO("VRAM at 0x%08x size is %u kiB\n",
 		 dev_priv->vram_start, dev_priv->vram_size / 1024);
 	DRM_INFO("MMIO at 0x%08x size is %u kiB\n",
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index a341946..d1196c8 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -185,6 +185,8 @@ struct vmw_private {
 	uint32_t capabilities;
 	uint32_t max_gmr_descriptors;
 	uint32_t max_gmr_ids;
+	uint32_t max_gmr_pages;
+	uint32_t memory_size;
 	bool has_gmr;
 	struct mutex hw_mutex;
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c
index ac6e0d1..5f71715 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c
@@ -40,6 +40,8 @@ struct vmwgfx_gmrid_man {
 	spinlock_t lock;
 	struct ida gmr_ida;
 	uint32_t max_gmr_ids;
+	uint32_t max_gmr_pages;
+	uint32_t used_gmr_pages;
 };
 
 static int vmw_gmrid_man_get_node(struct ttm_mem_type_manager *man,
@@ -49,33 +51,50 @@ static int vmw_gmrid_man_get_node(struct ttm_mem_type_manager *man,
 {
 	struct vmwgfx_gmrid_man *gman =
 		(struct vmwgfx_gmrid_man *)man->priv;
-	int ret;
+	int ret = 0;
 	int id;
 
 	mem->mm_node = NULL;
 
-	do {
-		if (unlikely(ida_pre_get(&gman->gmr_ida, GFP_KERNEL) == 0))
-			return -ENOMEM;
+	spin_lock(&gman->lock);
+
+	if (gman->max_gmr_pages > 0) {
+		gman->used_gmr_pages += bo->num_pages;
+		if (unlikely(gman->used_gmr_pages > gman->max_gmr_pages))
+			goto out_err_locked;
+	}
 
+	do {
+		spin_unlock(&gman->lock);
+		if (unlikely(ida_pre_get(&gman->gmr_ida, GFP_KERNEL) == 0)) {
+			ret = -ENOMEM;
+			goto out_err;
+		}
 		spin_lock(&gman->lock);
-		ret = ida_get_new(&gman->gmr_ida, &id);
 
+		ret = ida_get_new(&gman->gmr_ida, &id);
 		if (unlikely(ret == 0 && id >= gman->max_gmr_ids)) {
 			ida_remove(&gman->gmr_ida, id);
-			spin_unlock(&gman->lock);
-			return 0;
+			ret = 0;
+			goto out_err_locked;
 		}
-
-		spin_unlock(&gman->lock);
-
 	} while (ret == -EAGAIN);
 
 	if (likely(ret == 0)) {
 		mem->mm_node = gman;
 		mem->start = id;
-	}
+		mem->num_pages = bo->num_pages;
+	} else
+		goto out_err_locked;
+
+	spin_unlock(&gman->lock);
+	return 0;
 
+out_err:
+	spin_lock(&gman->lock);
+out_err_locked:
+	gman->used_gmr_pages -= bo->num_pages;
+	spin_unlock(&gman->lock);
 	return ret;
 }
 
@@ -88,6 +107,7 @@ static void vmw_gmrid_man_put_node(struct ttm_mem_type_manager *man,
 	if (mem->mm_node) {
 		spin_lock(&gman->lock);
 		ida_remove(&gman->gmr_ida, mem->start);
+		gman->used_gmr_pages -= mem->num_pages;
 		spin_unlock(&gman->lock);
 		mem->mm_node = NULL;
 	}
@@ -96,6 +116,8 @@ static void vmw_gmrid_man_put_node(struct ttm_mem_type_manager *man,
 static int vmw_gmrid_man_init(struct ttm_mem_type_manager *man,
 			      unsigned long p_size)
 {
+	struct vmw_private *dev_priv =
+		container_of(man->bdev, struct vmw_private, bdev);
 	struct vmwgfx_gmrid_man *gman =
 		kzalloc(sizeof(*gman), GFP_KERNEL);
 
@@ -103,6 +125,8 @@ static int vmw_gmrid_man_init(struct ttm_mem_type_manager *man,
 		return -ENOMEM;
 
 	spin_lock_init(&gman->lock);
+	gman->max_gmr_pages = dev_priv->max_gmr_pages;
+	gman->used_gmr_pages = 0;
 	ida_init(&gman->gmr_ida);
 	gman->max_gmr_ids = p_size;
 	man->priv = (void *) gman;
-- 
1.7.4.4