sna: Limit the tile size for uploading into large pixmaps

As we may have a constrained aperture, we need to be careful not to
exceed our resources limits when uploading the pixel data. (For example,
fitting two of the maximum bo into a single batch may fail due to
fragmentation of the GATT.) So be cautious and use more tiles to reduce
the size of each individual batch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

4 files changed, 31 insertions, 9 deletions

diff --git a/src/sna/kgem.c b/src/sna/kgem.c
index fff2d19b..7019638a 100644
--- a/src/sna/kgem.c
+++ b/src/sna/kgem.c
@@ -672,9 +672,15 @@ void kgem_init(struct kgem *kgem, int fd, struct pci_device *dev, int gen)
 	}
 	if (kgem->max_gpu_size > kgem->max_cpu_size)
 		kgem->max_gpu_size = kgem->max_cpu_size;
-
-	DBG(("%s: max object size (tiled=%d, linear=%d)\n",
-	     __FUNCTION__, kgem->max_gpu_size, kgem->max_cpu_size));
+	kgem->max_tile_size = kgem->aperture_total / 4;
+	if (kgem->max_tile_size < kgem->max_gpu_size / 2)
+		kgem->max_tile_size = kgem->max_gpu_size / 2;
+
+	DBG(("%s: max object size (gpu=%d, cpu=%d, tile=%d)\n",
+	     __FUNCTION__,
+	     kgem->max_gpu_size,
+	     kgem->max_cpu_size,
+	     kgem->max_tile_size));
 
 	/* Convert the aperture thresholds to pages */
 	kgem->aperture_low /= PAGE_SIZE;
diff --git a/src/sna/kgem.h b/src/sna/kgem.h
index f3869673..fea2d456 100644
--- a/src/sna/kgem.h
+++ b/src/sna/kgem.h
@@ -161,7 +161,7 @@ struct kgem {
 	uint32_t aperture_total, aperture_high, aperture_low, aperture_mappable;
 	uint32_t aperture, aperture_fenced;
 	uint32_t min_alignment;
-	uint32_t max_gpu_size, max_cpu_size, max_object_size;
+	uint32_t max_tile_size, max_gpu_size, max_cpu_size, max_object_size;
 	uint32_t partial_buffer_size;
 
 	void (*context_switch)(struct kgem *kgem, int new_mode);
diff --git a/src/sna/sna_io.c b/src/sna/sna_io.c
index 14a79013..4f86f8de 100644
--- a/src/sna/sna_io.c
+++ b/src/sna/sna_io.c
@@ -62,7 +62,8 @@ box_intersect(BoxPtr a, const BoxRec *b)
 static inline bool must_tile(struct sna *sna, int width, int height)
 {
 	return (width  > sna->render.max_3d_size ||
-		height > sna->render.max_3d_size);
+		height > sna->render.max_3d_size ||
+		width * height * 4 > sna->kgem.max_tile_size);
 }
 
 static void read_boxes_inplace(struct kgem *kgem,
@@ -199,6 +200,9 @@ fallback:
 
 			step = MIN(sna->render.max_3d_size,
 				   8*(MAXSHORT&~63) / dst->drawable.bitsPerPixel);
+			while (step * step * 4 > sna->kgem.max_tile_size)
+				step /= 2;
+
 			DBG(("%s: tiling download, using %dx%d tiles\n",
 			     __FUNCTION__, step, step));
 
@@ -577,6 +581,9 @@ fallback:
 
 			step = MIN(sna->render.max_3d_size,
 				   8*(MAXSHORT&~63) / dst->drawable.bitsPerPixel);
+			while (step * step * 4 > sna->kgem.max_tile_size)
+				step /= 2;
+
 			DBG(("%s: tiling upload, using %dx%d tiles\n",
 			     __FUNCTION__, step, step));
 
diff --git a/src/sna/sna_tiling.c b/src/sna/sna_tiling.c
index 52572bc6..eac664e3 100644
--- a/src/sna/sna_tiling.c
+++ b/src/sna/sna_tiling.c
@@ -138,7 +138,11 @@ sna_tiling_composite_done(struct sna *sna,
 {
 	struct sna_tile_state *tile = op->u.priv;
 	struct sna_composite_op tmp;
-	int x, y, n, step = sna->render.max_3d_size;
+	int x, y, n, step;
+
+	step = sna->render.max_3d_size;
+	while (step * step * 4 > sna->kgem.max_tile_size)
+		step /= 2;
 
 	DBG(("%s -- %dx%d, count=%d\n", __FUNCTION__,
 	     tile->width, tile->height, tile->rect_count));
@@ -318,21 +322,26 @@ sna_tiling_fill_boxes(struct sna *sna,
 {
 	RegionRec region, tile, this;
 	struct kgem_bo *bo;
+	int step;
 	Bool ret = FALSE;
 
 	pixman_region_init_rects(&region, box, n);
 
+	step = sna->render.max_3d_size;
+	while (step * step * 4 > sna->kgem.max_tile_size)
+		step /= 2;
+
 	DBG(("%s (op=%d, format=%x, color=(%04x,%04x,%04x, %04x), tile.size=%d, box=%dx[(%d, %d), (%d, %d)])\n",
 	     __FUNCTION__, op, (int)format,
 	     color->red, color->green, color->blue, color->alpha,
-	     sna->render.max_3d_size, n,
+	     step, n,
 	     region.extents.x1, region.extents.y1,
 	     region.extents.x2, region.extents.y2));
 
 	for (tile.extents.y1 = tile.extents.y2 = region.extents.y1;
 	     tile.extents.y2 < region.extents.y2;
 	     tile.extents.y1 = tile.extents.y2) {
-		tile.extents.y2 = tile.extents.y1 + sna->render.max_3d_size;
+		tile.extents.y2 = tile.extents.y1 + step;
 		if (tile.extents.y2 > region.extents.y2)
 			tile.extents.y2 = region.extents.y2;
 
@@ -341,7 +350,7 @@ sna_tiling_fill_boxes(struct sna *sna,
 		     tile.extents.x1 = tile.extents.x2) {
 			PixmapRec tmp;
 
-			tile.extents.x2 = tile.extents.x1 + sna->render.max_3d_size;
+			tile.extents.x2 = tile.extents.x1 + step;
 			if (tile.extents.x2 > region.extents.x2)
 				tile.extents.x2 = region.extents.x2;