Revert SMResource splitting fix, the problem was the test

cuda_core/cuda/core/_device_resources.pxd

@@ -2,8 +2,6 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-cimport cython
-
 from cuda.bindings cimport cydriver
 from cuda.core._resource_handles cimport ContextHandle, GreenCtxHandle
 
@@ -17,7 +15,6 @@ cdef class SMResource:
         unsigned int _flags
         bint _is_usable
         object __weakref__
-        cython.pymutex _split_mutex
 
     @staticmethod
     cdef SMResource _from_dev_resource(cydriver.CUdevResource res, int device_id)

cuda_core/cuda/core/_device_resources.pyx

@@ -498,11 +498,10 @@ cdef class SMResource:
         )
         _resolve_group_count(opts)
         _check_green_ctx_support()
-        with self._split_mutex:
-            if _can_use_structured_sm_split():
-                return _split_with_general_api(self, opts, dry_run)
-            # SplitByCount requires the same 12.4+ as green ctx support (already checked above)
-            return _split_with_count_api(self, opts, dry_run)
+        if _can_use_structured_sm_split():
+            return _split_with_general_api(self, opts, dry_run)
+        # SplitByCount requires the same 12.4+ as green ctx support (already checked above)
+        return _split_with_count_api(self, opts, dry_run)
 
 
 cdef class WorkqueueResource:

cuda_core/tests/conftest.py

@@ -131,6 +131,18 @@ def wrapper(*args, **kwargs):
                 kwargs["mempool_device_x2"] = _mempool_device_impl(2)
             if "mempool_device_x3" in kwargs:
                 kwargs["mempool_device_x3"] = _mempool_device_impl(3)
+
+            # These are used by test_green_context.py.  The original fixtures include
+            # pytest.skip() but that should have correctly fired by this time.
+            if "sm_resource" in kwargs:
+                kwargs["sm_resource"] = device.resources.sm
+            if "wq_resource" in kwargs:
+                kwargs["wq_resource"] = device.resources.workqueue
+            if "green_ctx" in kwargs:
+                from cuda.core import ContextOptions, SMResourceOptions
+
+                groups, _ = device.resources.sm.split(SMResourceOptions(count=None))
+                kwargs["green_ctx"] = device.create_context(ContextOptions(resources=[groups[0]]))
             return func(*args, **kwargs)
 
     wrapper._cuda_core_worker_cuda_wrapped = True

cuda_core/tests/test_green_context.py

@@ -40,6 +40,8 @@
 # ---------------------------------------------------------------------------
 # Fixtures
 # ---------------------------------------------------------------------------
+# Note that the following fixtures (except fill_kernel) require per-thread setup
+# and are currently special cased to work with pytest-run-parallel in conftest.
 
 
 @pytest.fixture