From b1d4db0339c545fc21441582a3a3425322bad506 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Fri, 23 Feb 2018 23:25:52 -0600
Subject: [PATCH 1/3] Fix vim section bracketing

---
 loopy/kernel/tools.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/loopy/kernel/tools.py b/loopy/kernel/tools.py
index 15db06ad7..f2104ca76 100644
--- a/loopy/kernel/tools.py
+++ b/loopy/kernel/tools.py
@@ -1391,7 +1391,7 @@ def draw_dependencies_as_unicode_arrows(
             if value is None:
                 del columns_in_use[col]
 
-        # }}
+        # }}}
 
         processed_ids.add(insn.id)
 
-- 
GitLab


From f318819dcf6903e619d297ca3940f43a6dfd08a6 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Fri, 23 Feb 2018 23:28:17 -0600
Subject: [PATCH 2/3] Ensure the scheduler generator chain is GC'd before
 resetting the recursion limit

---
 loopy/schedule/__init__.py | 39 ++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

diff --git a/loopy/schedule/__init__.py b/loopy/schedule/__init__.py
index b196b343e..f40a943b0 100644
--- a/loopy/schedule/__init__.py
+++ b/loopy/schedule/__init__.py
@@ -29,6 +29,8 @@ import sys
 import islpy as isl
 from loopy.diagnostic import warn_with_kernel, LoopyError  # noqa
 
+from pytools import MinRecursionLimit
+
 from pytools.persistent_dict import WriteOncePersistentDict
 from loopy.tools import LoopyKeyBuilder
 from loopy.version import DATA_MODEL_VERSION
@@ -1810,12 +1812,27 @@ def insert_barriers(kernel, schedule, synchronization_kind, verify_only, level=0
 # }}}
 
 
+class MinRecursionLimitForScheduling(MinRecursionLimit):
+    def __init__(self, kernel):
+        MinRecursionLimit.__init__(self,
+                len(kernel.instructions) * 2 + len(kernel.all_inames()) * 4)
+
+
 # {{{ main scheduling entrypoint
 
 def generate_loop_schedules(kernel, debug_args={}):
-    from pytools import MinRecursionLimit
-    with MinRecursionLimit(max(len(kernel.instructions) * 2,
-                               len(kernel.all_inames()) * 4)):
+    """
+    .. warning::
+
+        This function needs to be called inside (another layer) of a
+        :class:`MinRecursionLimitForScheduling` context manager, and the
+        context manager needs to end *after* the last reference to the
+        generators has gone out of scope. Otherwise, the high-recursion-limit
+        generator chain may not be successfully garbage-collected and cause an
+        internal error in the Python runtime.
+    """
+
+    with MinRecursionLimitForScheduling(kernel):
         for sched in generate_loop_schedules_inner(kernel, debug_args=debug_args):
             yield sched
 
@@ -2003,6 +2020,19 @@ schedule_cache = WriteOncePersistentDict(
         key_builder=LoopyKeyBuilder())
 
 
+def _get_one_scheduled_kernel_inner(kernel):
+    # This helper function exists to ensure that the generator chain is fully
+    # out of scope after the function returns. This allows it to be
+    # garbage-collected in the exit handler of the
+    # MinRecursionLimitForScheduling context manager in the surrounding
+    # function, because it possilby cannot be safely collected with a lower
+    # recursion limit without crashing the Python runtime.
+    #
+    # See https://gitlab.tiker.net/inducer/sumpy/issues/31 for context.
+
+    return next(iter(generate_loop_schedules(kernel)))
+
+
 def get_one_scheduled_kernel(kernel):
     from loopy import CACHING_ENABLED
 
@@ -2024,7 +2054,8 @@ def get_one_scheduled_kernel(kernel):
 
         logger.info("%s: schedule start" % kernel.name)
 
-        result = next(iter(generate_loop_schedules(kernel)))
+        with MinRecursionLimitForScheduling(kernel):
+            result = _get_one_scheduled_kernel_inner(kernel)
 
         logger.info("%s: scheduling done after %.2f s" % (
             kernel.name, time()-start_time))
-- 
GitLab


From 60ed8850abd9b73240990e7f78779814e426fd1c Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Fri, 23 Feb 2018 23:33:42 -0600
Subject: [PATCH 3/3] Bump pytools requirement

---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index b8f36d125..bd94ea7e7 100644
--- a/setup.py
+++ b/setup.py
@@ -37,7 +37,7 @@ setup(name="loo.py",
           ],
 
       install_requires=[
-          "pytools>=2017.6",
+          "pytools>=2018.1",
           "pymbolic>=2016.2",
           "genpy>=2016.1.2",
           "cgen>=2016.1",
-- 
GitLab