Author: Gregor Wegberg <[email protected]>
Branch: gc-incminimark-pinning
Changeset: r72157:8306f5ed33e9
Date: 2014-06-23 11:45 +0200
http://bitbucket.org/pypy/pypy/changeset/8306f5ed33e9/
Log: (hopefully) finish work on stepwise useage of the nursery
diff --git a/rpython/memory/gc/incminimark.py b/rpython/memory/gc/incminimark.py
--- a/rpython/memory/gc/incminimark.py
+++ b/rpython/memory/gc/incminimark.py
@@ -686,15 +686,23 @@
else:
self.minor_and_major_collection()
- def move_nursery_top(self, totalsize):
- size = self.nursery_cleanup
- ll_assert(self.nursery_real_top - self.nursery_top >= size,
- "nursery_cleanup not a divisor of nursery_size - initial_cleanup")
- ll_assert(llmemory.raw_malloc_usage(totalsize) <= size,
- "totalsize > nursery_cleanup")
+ def try_move_nursery_top(self, totalsize):
+ """Tries to move 'self.nursery_top' to accommodate
+ an object of 'totalsize'. Returns 'True' on success, otherwise
+ 'False'. In case of failing (returned 'False') a minor collection
+ is needed."""
+
+ # in general we always move 'self.nursery_top' by
'self.nursery_cleanup'.
+ # However, because of the presence of pinned objects there are cases
where
+ # the GC can't move by 'self.nursery_cleanup' without overflowing the
arena.
+ # For such a case we use the space left in the nursery.
+ size = min(self.nursery_cleanup, self.nursery_real_top -
self.nursery_top)
+ if llmemory.raw_malloc_usage(totalsize) > size:
+ return False
llarena.arena_reset(self.nursery_top, size, 2)
self.nursery_top += size
- move_nursery_top._always_inline_ = True
+ return True
+ try_move_nursery_top._always_inline_ = True
def collect_and_reserve(self, prev_result, totalsize):
"""To call when nursery_free overflows nursery_top.
@@ -728,10 +736,9 @@
else:
#
# no barriers (i.e. pinned objects) after 'nursery_free'.
- # if possible just enlarge the used part of the nursery.
- # otherwise we are forced to clean up the nursery.
- if self.nursery_top < self.nursery_real_top:
- self.move_nursery_top(totalsize)
+ # If possible just enlarge the used part of the nursery.
+ # Otherwise we are forced to clean up the nursery.
+ if self.try_move_nursery_top(totalsize):
return prev_result
#
self.minor_collection()
@@ -1623,13 +1630,16 @@
# reset everything after the last pinned object till the end of the
arena
llarena.arena_reset(prev, self.nursery_real_top - prev, 0)
#
- # make sure we have some clean space to use after a minor collection
- if self.nursery_real_top - prev >= self.nursery_cleanup:
+ # We assume that there are only a few pinned objects. Therefore, if
there
+ # is 'self.nursery_cleanup' space between the nursery's start
('self.nursery')
+ # and the last pinned object ('prev'), we conclude that there is
enough zeroed
+ # space inside the arena to use for new allocation. Otherwise we fill
+ # the nursery with zeros for 'self.nursery_cleanup' of space.
+ if prev - self.nursery >= self.nursery_cleanup:
+ nursery_barriers.append(prev)
+ else:
llarena.arena_reset(prev, self.nursery_cleanup, 2)
nursery_barriers.append(prev + self.nursery_cleanup)
- else:
- llarena.arena_reset(prev, self.nursery_real_top - prev, 2)
- nursery_barriers.append(self.nursery_real_top)
#
self.nursery_barriers = nursery_barriers
self.surviving_pinned_objects.delete()
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