On 11.10.2017 01:25, Gurchetan Singh wrote:
"The GL state tracker, which is the only one that runs into the
multi-context subtleties (due to share groups), already guarantees that
sampler views are destroyed before their context of creation is destroyed."
How does the GL state tracker guarantee this? Does this guarantee also
apply to pipe_surfaces? Context: ChromiumOS previously ran into an
issue where sampler_views and pipe_surfaces outlived the context that
created them [1], and we have technical debt [2][3][4] emanating from
this. It would be great to remove this, if things have changed in the
Gallium code.
st/mesa creates sampler views of two types:
1. There are sampler views associated to normal textures, which are
created in st_sampler_view.c. Those sampler views are always created by
the context that uses them; when the context is destroyed, they are all
released (via st_destroy_context --> destroy_tex_sampler_cb).
2. Temporary sampler views are created in some places (e.g. for blits),
but those are released immediately after setting them in the
pipe_context via cso.
I'm not so sure about pipe_surface objects, nor about other state trackers.
Unfortunately, none of your links is particularly informative about the
sequence of events that lead to whatever problems they were trying to fix :/
All I can say is that I've never seen a crash related to a sampler view
being destroyed after its owning context with Mesa master, but I realize
that may not be too helpful...
Cheers,
Nicolai
[1]
https://lists.freedesktop.org/archives/mesa-dev/2011-September/011578.html
[2]
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/mesa/files/10.3-state_tracker-gallium-fix-crash-with-st_renderbuffer.patch
[3]
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/mesa/files/10.3-state_tracker-gallium-fix-crash-with-st_renderbuffer-freedreno.patch
[4]
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/mesa/files/12.1-radeonsi-sampler_view_destroy.patch
On Tue, Oct 10, 2017 at 2:42 PM, Nicolai Hähnle <nhaeh...@gmail.com
<mailto:nhaeh...@gmail.com>> wrote:
Same as on IRC:
On 10.10.2017 04:06, Marek Olšák wrote:
Is there any difference with piglit/drawoverhead?
Yes, there is.
If yes, would this be useful?
https://patchwork.freedesktop.org/patch/41241/
<https://patchwork.freedesktop.org/patch/41241/>
Surprisingly, not that much. I'm going to think though a couple of
other options, but want to already push patch #3; I sent a version
that is rebased on master and disentangled from the locking stuff.
Cheers,
Nicolai
Marek
On Fri, Oct 6, 2017 at 10:38 PM, Nicolai Hähnle
<nhaeh...@gmail.com <mailto:nhaeh...@gmail.com>> wrote:
From: Nicolai Hähnle <nicolai.haeh...@amd.com
<mailto:nicolai.haeh...@amd.com>>
r600 expects the context that created the sampler view to
still be alive
(there is a per-context list of sampler views).
svga currently bails when the context of destruction is not
the same as
creation.
The GL state tracker, which is the only one that runs into the
multi-context subtleties (due to share groups), already
guarantees that
sampler views are destroyed before their context of creation
is destroyed.
Most drivers are context-agnostic, so the warning message in
pipe_sampler_view_release doesn't really make sense.
---
src/gallium/auxiliary/util/u_inlines.h | 16
++++++++++------
src/gallium/include/pipe/p_context.h | 10 ++++++++++
src/mesa/state_tracker/st_sampler_view.c | 1 -
3 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/src/gallium/auxiliary/util/u_inlines.h
b/src/gallium/auxiliary/util/u_inlines.h
index 79f62c32266..790352d7800 100644
--- a/src/gallium/auxiliary/util/u_inlines.h
+++ b/src/gallium/auxiliary/util/u_inlines.h
@@ -142,45 +142,49 @@ pipe_resource_reference(struct
pipe_resource **ptr, struct pipe_resource *tex)
struct pipe_resource *next = old_tex->next;
old_tex->screen->resource_destroy(old_tex->screen, old_tex);
old_tex = next;
} while
(pipe_reference_described(&old_tex->reference, NULL,
(debug_reference_descriptor)debug_describe_resource));
}
*ptr = tex;
}
+/**
+ * Set *ptr to \p view with proper reference counting.
+ *
+ * The caller must guarantee that \p view and *ptr must
have been created in
+ * the same context (if they exist), and that this must be
the current context.
+ */
static inline void
pipe_sampler_view_reference(struct pipe_sampler_view
**ptr, struct pipe_sampler_view *view)
{
struct pipe_sampler_view *old_view = *ptr;
if (pipe_reference_described(&(*ptr)->reference,
&view->reference,
(debug_reference_descriptor)debug_describe_sampler_view))
old_view->context->sampler_view_destroy(old_view->context,
old_view);
*ptr = view;
}
/**
* Similar to pipe_sampler_view_reference() but always
set the pointer to
- * NULL and pass in an explicit context. Passing an
explicit context is a
- * work-around for fixing a dangling context pointer
problem when textures
- * are shared by multiple contexts. XXX fix this someday.
+ * NULL and pass in the current context explicitly.
+ *
+ * If *ptr is non-NULL, it may refer to a view that was
created in a different
+ * context (however, that context must still be alive).
*/
static inline void
pipe_sampler_view_release(struct pipe_context *ctx,
struct pipe_sampler_view **ptr)
{
struct pipe_sampler_view *old_view = *ptr;
- if (*ptr && (*ptr)->context != ctx) {
- debug_printf_once(("context mis-match in
pipe_sampler_view_release()\n"));
- }
if (pipe_reference_described(&(*ptr)->reference, NULL,
(debug_reference_descriptor)debug_describe_sampler_view)) {
ctx->sampler_view_destroy(ctx, old_view);
}
*ptr = NULL;
}
static inline void
pipe_so_target_reference(struct pipe_stream_output_target
**ptr,
struct pipe_stream_output_target
*target)
diff --git a/src/gallium/include/pipe/p_context.h
b/src/gallium/include/pipe/p_context.h
index 4609d4dbf23..087836d1c0c 100644
--- a/src/gallium/include/pipe/p_context.h
+++ b/src/gallium/include/pipe/p_context.h
@@ -501,20 +501,30 @@ struct pipe_context {
void (*fence_server_sync)(struct pipe_context *pipe,
struct pipe_fence_handle
*fence);
/**
* Create a view on a texture to be used by a shader
stage.
*/
struct pipe_sampler_view *
(*create_sampler_view)(struct pipe_context *ctx,
struct pipe_resource *texture,
const struct pipe_sampler_view *templat);
+ /**
+ * Destroy a view on a texture.
+ *
+ * \param ctx the current context
+ * \param view the view to be destroyed
+ *
+ * \note The current context may not be the context in
which the view was
+ * created (view->context). However, the caller
must guarantee that
+ * the context which created the view is still alive.
+ */
void (*sampler_view_destroy)(struct pipe_context *ctx,
struct pipe_sampler_view
*view);
/**
* Get a surface which is a "view" into a resource,
used by
* render target / depth stencil stages.
*/
struct pipe_surface *(*create_surface)(struct
pipe_context *ctx,
struct
pipe_resource *resource,
diff --git a/src/mesa/state_tracker/st_sampler_view.c
b/src/mesa/state_tracker/st_sampler_view.c
index fbf0aaeb03a..d1715a888d9 100644
--- a/src/mesa/state_tracker/st_sampler_view.c
+++ b/src/mesa/state_tracker/st_sampler_view.c
@@ -109,21 +109,20 @@ st_texture_release_sampler_view(struct
st_context *st,
/**
* Release all sampler views attached to the given
texture object, regardless
* of the context.
*/
void
st_texture_release_all_sampler_views(struct st_context *st,
struct
st_texture_object *stObj)
{
GLuint i;
- /* XXX This should use sampler_views[i]->pipe, not
st->pipe */
for (i = 0; i < stObj->num_sampler_views; ++i)
pipe_sampler_view_release(st->pipe,
&stObj->sampler_views[i]);
}
void
st_texture_free_sampler_views(struct st_texture_object
*stObj)
{
free(stObj->sampler_views);
stObj->sampler_views = NULL;
--
2.11.0
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