On 07.10.2017 00:36, Roland Scheidegger wrote:
I can't help but think that there'd be none of those problems if those
views were actually used as specced by gallium initially: all sampler
views (and surfaces) are per context, and they simply cannot be used in
another context.
That is actually the case today, with the exception that when a texture
object is destroyed, all of sampler views are destroyed as well, from
within whatever happens to be the current context. (This can be solved
with some kind of "orphaned" list, but I'd rather not do that in st/mesa.)
The problem is that when we need a sampler view for a texture, we have
(a) the context pointer and (b) the texture object pointer, and we need
to map those to a sampler view. This happens via a mutable per-texture
object structure, access to which must be protected somehow.
Cheers,
Nicolai
Roland
Am 06.10.2017 um 22:38 schrieb Nicolai Hähnle:
Hi all,
This series is a first result of debugging some random crashes in dEQP's
multi-threaded EGL tests.
The OpenGL spec is pretty clear that application must not modify a texture
in one context while simultaneously using it for texturing (or even
modifying) it in another context. Texturing simultaneously in multiple
contexts is fine, though.
This can lead to races when st_finalize_texture is called simultaneously
for two contexts, or if two contexts simultaneously attempt to access the
sampler view array of a texture.
This series should fix most (all?) issues where our internal data
structures could become corrupted. I am aware of one remaining corner
case that could lead to rendering corruption. It appears rather non-trivial
to fix, and it is documented in a comment of patch #5.
Please review!
Thanks,
Nicolai
--
src/gallium/auxiliary/util/u_inlines.h | 16 ++-
src/gallium/include/pipe/p_context.h | 10 ++
src/mesa/state_tracker/st_atom_sampler.c | 12 +-
src/mesa/state_tracker/st_atom_texture.c | 12 --
src/mesa/state_tracker/st_cb_texture.c | 59 +++++++--
src/mesa/state_tracker/st_manager.c | 3 +
src/mesa/state_tracker/st_sampler_view.c | 137 +++++++++++++++++----
src/mesa/state_tracker/st_sampler_view.h | 7 ++
src/mesa/state_tracker/st_texture.h | 23 +++-
9 files changed, 205 insertions(+), 74 deletions(-)
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