Author: Armin Rigo <[email protected]>
Branch:
Changeset: r67761:e2cc638553ad
Date: 2013-10-31 09:18 +0100
http://bitbucket.org/pypy/pypy/changeset/e2cc638553ad/
Log: Tweak 'more_objects_to_trace' to avoid recording *all* surviving
young objects during the marking phase.
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
@@ -1390,6 +1390,15 @@
if self.young_rawmalloced_objects:
self.remove_young_arrays_from_old_objects_pointing_to_young()
#
+ # A special step in the STATE_MARKING phase.
+ if self.gc_state == STATE_MARKING:
+ # Copy the 'old_objects_pointing_to_young' list so far to
+ # 'more_objects_to_trace'. Turn black objects back to gray.
+ # This is because these are precisely the old objects that
+ # have been modified and need rescanning.
+ self.old_objects_pointing_to_young.foreach(
+ self._add_to_more_objects_to_trace, None)
+ #
# First, find the roots that point to young objects. All nursery
# objects found are copied out of the nursery, and the occasional
# young raw-malloced object is flagged with GCFLAG_VISITED_RMY.
@@ -1459,10 +1468,14 @@
# then the write_barrier must have ensured that the prebuilt
# GcStruct is in the list self.old_objects_pointing_to_young.
debug_start("gc-minor-walkroots")
+ if self.gc_state == STATE_MARKING:
+ callback = IncrementalMiniMarkGC._trace_drag_out1_marking_phase
+ else:
+ callback = IncrementalMiniMarkGC._trace_drag_out1
self.root_walker.walk_roots(
- IncrementalMiniMarkGC._trace_drag_out1, # stack roots
- IncrementalMiniMarkGC._trace_drag_out1, # static in prebuilt
non-gc
- None) # static in prebuilt gc
+ callback, # stack roots
+ callback, # static in prebuilt non-gc
+ None) # static in prebuilt gc
debug_stop("gc-minor-walkroots")
def collect_cardrefs_to_nursery(self):
@@ -1522,21 +1535,14 @@
interval_start = next_byte_start
#
# If we're incrementally marking right now, sorry, we also
- # need to add the object to 'objects_to_trace' and have it
- # fully traced very soon.
+ # need to add the object to 'more_objects_to_trace' and have
+ # it fully traced once at the end of the current marking phase.
if self.gc_state == STATE_MARKING:
self.header(obj).tid &= ~GCFLAG_VISITED
self.more_objects_to_trace.append(obj)
def collect_oldrefs_to_nursery(self):
- if self.gc_state == STATE_MARKING:
- self._collect_oldrefs_to_nursery(True)
- else:
- self._collect_oldrefs_to_nursery(False)
-
- @specialize.arg(1)
- def _collect_oldrefs_to_nursery(self, state_is_marking):
# Follow the old_objects_pointing_to_young list and move the
# young objects they point to out of the nursery.
oldlist = self.old_objects_pointing_to_young
@@ -1553,15 +1559,6 @@
# have this flag set after a nursery collection.
self.header(obj).tid |= GCFLAG_TRACK_YOUNG_PTRS
#
- # If the incremental major collection is currently at
- # STATE_MARKING, then we must add to 'objects_to_trace' all
- # objects that go through 'old_objects_pointing_to_young'.
- # This basically turns black objects gray again, but also
- # makes sure that we see otherwise-white objects.
- if state_is_marking:
- self.header(obj).tid &= ~GCFLAG_VISITED
- self.more_objects_to_trace.append(obj)
- #
# Trace the 'obj' to replace pointers to nursery with pointers
# outside the nursery, possibly forcing nursery objects out
# and adding them to 'old_objects_pointing_to_young' as well.
@@ -1584,15 +1581,21 @@
def _trace_drag_out1(self, root):
- # In the MARKING state, we must also record this old object,
- # if it is not VISITED yet.
- if self.gc_state == STATE_MARKING:
- obj = root.address[0]
- if not self.is_in_nursery(obj):
- if not self.header(obj).tid & GCFLAG_VISITED:
- self.more_objects_to_trace.append(obj)
+ self._trace_drag_out(root, None)
+
+ def _trace_drag_out1_marking_phase(self, root):
+ self._trace_drag_out(root, None)
#
- self._trace_drag_out(root, None)
+ # We are in the MARKING state: we must also record this object
+ # if it was young. Don't bother with old objects in general,
+ # as they are anyway added to 'more_objects_to_trace' if they
+ # are modified (see _add_to_more_objects_to_trace). But we do
+ # need to record the not-visited-yet (white) old objects. So
+ # as a conservative approximation, we need to add the object to
+ # the list if and only if it doesn't have GCFLAG_VISITED yet.
+ obj = root.address[0]
+ if not self.header(obj).tid & GCFLAG_VISITED:
+ self.more_objects_to_trace.append(obj)
def _trace_drag_out(self, root, ignored):
obj = root.address[0]
@@ -1668,12 +1671,6 @@
if self.has_gcptr(typeid):
# we only have to do it if we have any gcptrs
self.old_objects_pointing_to_young.append(newobj)
- else:
- # we don't need to add this to 'old_objects_pointing_to_young',
- # but in the STATE_MARKING phase we still need this bit...
- if self.gc_state == STATE_MARKING:
- self.header(newobj).tid &= ~GCFLAG_VISITED
- self.more_objects_to_trace.append(newobj)
_trace_drag_out._always_inline_ = True
@@ -1756,6 +1753,10 @@
old.append(new.pop())
new.delete()
+ def _add_to_more_objects_to_trace(self, obj, ignored):
+ self.header(obj).tid &= ~GCFLAG_VISITED
+ self.more_objects_to_trace.append(obj)
+
def minor_and_major_collection(self):
# First, finish the current major gc, if there is one in progress.
# This is a no-op if the gc_state is already STATE_SCANNING.
_______________________________________________
pypy-commit mailing list
[email protected]
https://mail.python.org/mailman/listinfo/pypy-commit
