Module: Mesa
Branch: master
Commit: 2f351408467a1d2e46927b8df0d3047b67ae2623
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=2f351408467a1d2e46927b8df0d3047b67ae2623
Author: Mathias Fröhlich <mathias.froehl...@web.de>
Date: Sat Feb 3 15:22:33 2018 +0100
mesa: Use atomics for shared VAO reference counts.
VAOs will be used in the next change as immutable object across multiple
contexts. Only reference counting may write concurrently on the VAO. So,
make the reference count thread safe for those and only those VAO objects.
v3: Use bool/true/false for gl_vertex_array_object::SharedAndImmutable.
Signed-off-by: Mathias Fröhlich <mathias.froehl...@web.de>
Reviewed-by: Brian Paul <bri...@vmware.com>
---
src/mesa/main/arrayobj.c | 35 ++++++++++++++++++++++++++++++-----
src/mesa/main/arrayobj.h | 9 +++++++++
src/mesa/main/mtypes.h | 7 +++++++
3 files changed, 46 insertions(+), 5 deletions(-)
diff --git a/src/mesa/main/arrayobj.c b/src/mesa/main/arrayobj.c
index cf9c5d7ecc..2526404fda 100644
--- a/src/mesa/main/arrayobj.c
+++ b/src/mesa/main/arrayobj.c
@@ -53,6 +53,7 @@
#include "varray.h"
#include "main/dispatch.h"
#include "util/bitscan.h"
+#include "util/u_atomic.h"
const GLubyte
@@ -331,10 +332,16 @@ _mesa_reference_vao_(struct gl_context *ctx,
/* Unreference the old array object */
struct gl_vertex_array_object *oldObj = *ptr;
- assert(oldObj->RefCount > 0);
- oldObj->RefCount--;
+ bool deleteFlag;
+ if (oldObj->SharedAndImmutable) {
+ deleteFlag = p_atomic_dec_zero(&oldObj->RefCount);
+ } else {
+ assert(oldObj->RefCount > 0);
+ oldObj->RefCount--;
+ deleteFlag = (oldObj->RefCount == 0);
+ }
- if (oldObj->RefCount == 0)
+ if (deleteFlag)
_mesa_delete_vao(ctx, oldObj);
*ptr = NULL;
@@ -343,9 +350,13 @@ _mesa_reference_vao_(struct gl_context *ctx,
if (vao) {
/* reference new array object */
- assert(vao->RefCount > 0);
+ if (vao->SharedAndImmutable) {
+ p_atomic_inc(&vao->RefCount);
+ } else {
+ assert(vao->RefCount > 0);
+ vao->RefCount++;
+ }
- vao->RefCount++;
*ptr = vao;
}
}
@@ -407,6 +418,7 @@ _mesa_initialize_vao(struct gl_context *ctx,
vao->Name = name;
vao->RefCount = 1;
+ vao->SharedAndImmutable = false;
/* Init the individual arrays */
for (i = 0; i < ARRAY_SIZE(vao->VertexAttrib); i++) {
@@ -452,6 +464,9 @@ _mesa_update_vao_derived_arrays(struct gl_context *ctx,
{
GLbitfield arrays = vao->NewArrays;
+ /* Make sure we do not run into problems with shared objects */
+ assert(!vao->SharedAndImmutable || vao->NewArrays == 0);
+
while (arrays) {
const int attrib = u_bit_scan(&arrays);
struct gl_vertex_array *array = &vao->_VertexArray[attrib];
@@ -465,6 +480,16 @@ _mesa_update_vao_derived_arrays(struct gl_context *ctx,
}
+void
+_mesa_set_vao_immutable(struct gl_context *ctx,
+ struct gl_vertex_array_object *vao)
+{
+ _mesa_update_vao_derived_arrays(ctx, vao);
+ vao->NewArrays = 0;
+ vao->SharedAndImmutable = true;
+}
+
+
bool
_mesa_all_varyings_in_vbos(const struct gl_vertex_array_object *vao)
{
diff --git a/src/mesa/main/arrayobj.h b/src/mesa/main/arrayobj.h
index 5de74505bb..8da5c9ffe0 100644
--- a/src/mesa/main/arrayobj.h
+++ b/src/mesa/main/arrayobj.h
@@ -81,6 +81,15 @@ extern void
_mesa_update_vao_derived_arrays(struct gl_context *ctx,
struct gl_vertex_array_object *vao);
+
+/**
+ * Mark the vao as shared and immutable, do remaining updates.
+ */
+extern void
+_mesa_set_vao_immutable(struct gl_context *ctx,
+ struct gl_vertex_array_object *vao);
+
+
/* Returns true if all varying arrays reside in vbos */
extern bool
_mesa_all_varyings_in_vbos(const struct gl_vertex_array_object *vao);
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index bdecd422a9..15f39cbacc 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1608,6 +1608,13 @@ struct gl_vertex_array_object
GLboolean EverBound;
/**
+ * Marked to true if the object is shared between contexts and immutable.
+ * Then reference counting is done using atomics and thread safe.
+ * Is used for dlist VAOs.
+ */
+ bool SharedAndImmutable;
+
+ /**
* Derived vertex attribute arrays
*
* This is a legacy data structure created from gl_array_attributes and
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