Author: Gregor Wegberg <[email protected]>
Branch: gc-incminimark-pinning
Changeset: r72810:f2e0b083a76b
Date: 2014-08-14 16:51 +0200
http://bitbucket.org/pypy/pypy/changeset/f2e0b083a76b/
Log: new GC flag that uses the same bit as GCFLAG_PINNED for parents
pointing to pinned objects.
Looks a bit cleaner than using GCFLAG_PINNED on old objects.
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
@@ -138,6 +138,14 @@
# details.
GCFLAG_PINNED = first_gcflag << 9
+# The following flag is set only on objects outside the nursery
+# (i.e. old objects). Therefore we can reuse GCFLAG_PINNED as it is used for
+# the same feature (object pinning) and GCFLAG_PINNED is only used on nursery
+# objects.
+# If this flag is set, the flagged object is already an element of
+# 'old_objects_pointing_to_pinned' and doesn't have to be added again.
+GCFLAG_PINNED_OBJECT_PARENT_KNOWN = GCFLAG_PINNED
+
_GCFLAG_FIRST_UNUSED = first_gcflag << 10 # the first unused bit
@@ -1676,6 +1684,7 @@
self.nursery_free = self.nursery
self.nursery_top = self.nursery_barriers.popleft()
+ # clear GCFLAG_PINNED_OBJECT_PARENT_KNOWN from all parents in the list.
self.old_objects_pointing_to_pinned.foreach(
self._reset_flag_old_objects_pointing_to_pinned, None)
@@ -1691,8 +1700,8 @@
debug_stop("gc-minor")
def _reset_flag_old_objects_pointing_to_pinned(self, obj, ignore):
- assert self.header(obj).tid & GCFLAG_PINNED
- self.header(obj).tid &= ~GCFLAG_PINNED
+ assert self.header(obj).tid & GCFLAG_PINNED_OBJECT_PARENT_KNOWN
+ self.header(obj).tid &= ~GCFLAG_PINNED_OBJECT_PARENT_KNOWN
def _visit_old_objects_pointing_to_pinned(self, obj, ignore):
self.trace(obj, self._trace_drag_out, obj)
@@ -1871,7 +1880,7 @@
hdr = self.header(obj)
# track parent of pinned object specially
if parent != llmemory.NULL and \
- not self.header(parent).tid & GCFLAG_PINNED:
+ not self.header(parent).tid &
GCFLAG_PINNED_OBJECT_PARENT_KNOWN:
#
self.old_objects_pointing_to_pinned.append(parent)
self.header(parent).tid |= GCFLAG_PINNED
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