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diff --git a/python/gevent/_greenlet_primitives.py b/python/gevent/_greenlet_primitives.py
new file mode 100644
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+++ b/python/gevent/_greenlet_primitives.py
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+# -*- coding: utf-8 -*-
+# copyright (c) 2018 gevent. See  LICENSE.
+# cython: auto_pickle=False,embedsignature=True,always_allow_keywords=False
+"""
+A collection of primitives used by the hub, and suitable for
+compilation with Cython because of their frequency of use.
+
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from weakref import ref as wref
+
+from greenlet import greenlet
+
+from gevent.exceptions import BlockingSwitchOutError
+
+
+# In Cython, we define these as 'cdef inline' functions. The
+# compilation unit cannot have a direct assignment to them (import
+# is assignment) without generating a 'lvalue is not valid target'
+# error.
+locals()['getcurrent'] = __import__('greenlet').getcurrent
+locals()['greenlet_init'] = lambda: None
+locals()['_greenlet_switch'] = greenlet.switch
+
+__all__ = [
+    'TrackedRawGreenlet',
+    'SwitchOutGreenletWithLoop',
+]
+
+class TrackedRawGreenlet(greenlet):
+
+    def __init__(self, function, parent):
+        greenlet.__init__(self, function, parent)
+        # See greenlet.py's Greenlet class. We capture the cheap
+        # parts to maintain the tree structure, but we do not capture
+        # the stack because that's too expensive for 'spawn_raw'.
+
+        current = getcurrent() # pylint:disable=undefined-variable
+        self.spawning_greenlet = wref(current)
+        # See Greenlet for how trees are maintained.
+        try:
+            self.spawn_tree_locals = current.spawn_tree_locals
+        except AttributeError:
+            self.spawn_tree_locals = {}
+            if current.parent:
+                current.spawn_tree_locals = self.spawn_tree_locals
+
+
+class SwitchOutGreenletWithLoop(TrackedRawGreenlet):
+    # Subclasses must define:
+    # - self.loop
+
+    # This class defines loop in its .pxd for Cython. This lets us avoid
+    # circular dependencies with the hub.
+
+    def switch(self):
+        switch_out = getattr(getcurrent(), 'switch_out', None) # pylint:disable=undefined-variable
+        if switch_out is not None:
+            switch_out()
+        return _greenlet_switch(self) # pylint:disable=undefined-variable
+
+    def switch_out(self):
+        raise BlockingSwitchOutError('Impossible to call blocking function in the event loop callback')
+
+def _init():
+    greenlet_init() # pylint:disable=undefined-variable
+
+_init()
+
+from gevent._util import import_c_accel
+import_c_accel(globals(), 'gevent.__greenlet_primitives')