[Mesa-dev] [PATCH v4 6/6] radeonsi: try to re-use previously deleted bindless descriptor slots

[Samuel Pitoiset]

Currently, when the array is full it is resized but it can grow
over and over because we don't try to re-use descriptor slots.

v4: - rebase on top of idalloc changes
v3: - use new idalloc gallium module

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/gallium/drivers/radeonsi/si_descriptors.c | 36 +++++++++++++++++++++------
 src/gallium/drivers/radeonsi/si_pipe.h        |  2 ++
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_descriptors.c b/src/gallium/drivers/radeonsi/si_descriptors.c
index f14fce103f..c869dac9bb 100644
--- a/src/gallium/drivers/radeonsi/si_descriptors.c
+++ b/src/gallium/drivers/radeonsi/si_descriptors.c
@@ -61,6 +61,7 @@
 #include "gfx9d.h"
 
 #include "util/hash_table.h"
+#include "util/u_idalloc.h"
 #include "util/u_format.h"
 #include "util/u_memory.h"
 #include "util/u_upload_mgr.h"
@@ -2335,23 +2336,27 @@ static void si_init_bindless_descriptors(struct si_context *sctx,
 	 * considered to be a valid handle.
 	 */
 	sctx->num_bindless_descriptors = 1;
+
+	/* Track which bindless slots are used (or not). */
+	util_idalloc_init(&sctx->bindless_used_slots);
+	util_idalloc_resize(&sctx->bindless_used_slots, num_elements);
+
+	/* Reserve slot 0 because it's an invalid handle for bindless. */
+	assert(!util_idalloc_alloc(&sctx->bindless_used_slots));
 }
 
 static void si_release_bindless_descriptors(struct si_context *sctx)
 {
 	si_release_descriptors(&sctx->bindless_descriptors);
+	util_idalloc_fini(&sctx->bindless_used_slots);
 }
 
-static unsigned
-si_create_bindless_descriptor(struct si_context *sctx, uint32_t *desc_list,
-			      unsigned size)
+static unsigned si_get_first_free_bindless_slot(struct si_context *sctx)
 {
 	struct si_descriptors *desc = &sctx->bindless_descriptors;
-	unsigned desc_slot, desc_slot_offset;
-
-	/* Reserve a new slot for this bindless descriptor. */
-	desc_slot = sctx->num_bindless_descriptors++;
+	unsigned desc_slot;
 
+	desc_slot = util_idalloc_alloc(&sctx->bindless_used_slots);
 	if (desc_slot >= desc->num_elements) {
 		/* The array of bindless descriptors is full, resize it. */
 		unsigned slot_size = desc->element_dw_size * 4;
@@ -2363,6 +2368,20 @@ si_create_bindless_descriptor(struct si_context *sctx, uint32_t *desc_list,
 		desc->num_active_slots = new_num_elements;
 	}
 
+	assert(desc_slot);
+	return desc_slot;
+}
+
+static unsigned
+si_create_bindless_descriptor(struct si_context *sctx, uint32_t *desc_list,
+			      unsigned size)
+{
+	struct si_descriptors *desc = &sctx->bindless_descriptors;
+	unsigned desc_slot, desc_slot_offset;
+
+	/* Find a free slot. */
+	desc_slot = si_get_first_free_bindless_slot(sctx);
+
 	/* For simplicity, sampler and image bindless descriptors use fixed
 	 * 16-dword slots for now. Image descriptors only need 8-dword but this
 	 * doesn't really matter because no real apps use image handles.
@@ -2475,6 +2494,9 @@ static void si_delete_texture_handle(struct pipe_context *ctx, uint64_t handle)
 
 	tex_handle = (struct si_texture_handle *)entry->data;
 
+	/* Allow this descriptor slot to be re-used. */
+	util_idalloc_free(&sctx->bindless_used_slots, tex_handle->desc_slot);
+
 	pipe_sampler_view_reference(&tex_handle->view, NULL);
 	_mesa_hash_table_remove(sctx->tex_handles, entry);
 	FREE(tex_handle);
diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
index 56c3b08188..8a475d3b05 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.h
+++ b/src/gallium/drivers/radeonsi/si_pipe.h
@@ -29,6 +29,7 @@
 #include "si_shader.h"
 
 #include "util/u_dynarray.h"
+#include "util/u_idalloc.h"
 
 #ifdef PIPE_ARCH_BIG_ENDIAN
 #define SI_BIG_ENDIAN 1
@@ -430,6 +431,7 @@ struct si_context {
 
 	/* Bindless descriptors. */
 	struct si_descriptors	bindless_descriptors;
+	struct util_idalloc	bindless_used_slots;
 	unsigned		num_bindless_descriptors;
 	bool			bindless_descriptors_dirty;
 	bool			graphics_bindless_pointer_dirty;
-- 
2.14.1