[pypy-commit] stmgc default: Backed out changeset: 191c168da60e (readding of objects during minor collections to old_objects_to_trace)

[Raemi]

Author: Remi Meier <remi.meier at gmail.com>
Branch: 
Changeset: r419:ff208391e85c
Date: 2013-07-19 11:51 +0200
http://bitbucket.org/pypy/stmgc/changeset/ff208391e85c/

Log:	Backed out changeset: 191c168da60e (readding of objects during minor
	collections to old_objects_to_trace)

diff --git a/c4/nursery.c b/c4/nursery.c
--- a/c4/nursery.c
+++ b/c4/nursery.c
@@ -125,9 +125,6 @@
 }
 
 /************************************************************/
-/* list for private/protected, old roots that need to be
-   kept in old_objects_to_trace */
-static __thread struct GcPtrList private_or_protected_roots = {0, 0, NULL};
 
 static inline gcptr create_old_object_copy(gcptr obj)
 {
@@ -207,22 +204,6 @@
                                    (revision_t)END_MARKER_ON)) {
             /* 'item' is a regular, non-null pointer */
             visit_if_young(end);
-            item = *end;
-            /* if private or protected, this object needs to be
-               traced again in the next minor_collect if it is
-               currently in old_objects_to_trace. Because then
-               it may be seen as write-ready in the view of
-               someone:
-               pw = write_barrier(); push_root(pw);
-               minor_collect(); pw = pop_root(); // pw still write-ready
-            */
-            if (item
-                && !(item->h_tid & GCFLAG_WRITE_BARRIER) /* not set in
-                                                          obj_to_trace*/
-                && (item->h_tid & GCFLAG_PRIVATE_FROM_PROTECTED
-                    || item->h_revision == stm_private_rev_num)) {
-                gcptrlist_insert(&private_or_protected_roots, item);
-            }
         }
         else if (item != NULL) {
             if (item == END_MARKER_OFF)
@@ -545,15 +526,10 @@
                d->num_read_objects_known_old);
         assert(gcptrlist_size(&d->private_from_protected) >=
                d->num_private_from_protected_known_old);
-#if 0
-        /* we could here force the following, but there is little point
-           and it's a bad idea to do things in this function that is
-           compiled only in debug mode */
         d->num_read_objects_known_old =
             gcptrlist_size(&d->list_of_read_objects);
         d->num_private_from_protected_known_old =
             gcptrlist_size(&d->private_from_protected);
-#endif
         return 0;
     }
     else {
diff --git a/c4/test/test_et.py b/c4/test/test_et.py
--- a/c4/test/test_et.py
+++ b/c4/test/test_et.py
@@ -205,6 +205,7 @@
     assert list_of_read_objects() == [p2]
 
 def test_write_barrier_after_minor_collect():
+    # should fail
     p = oalloc_refs(1)
     pw = lib.stm_write_barrier(p)
 
@@ -220,8 +221,10 @@
     assert pw.h_tid & GCFLAG_OLD
     rawsetptr(pw, 0, r)
 
-    # pw needs to be readded to old_objects_to_trace
-    # before the next minor gc in order for this test to pass
+    # pw not in old_objects_to_trace. A
+    # repeated write_barrier before
+    # rawsetptr() would fix that
+    
     lib.stm_push_root(r)
     minor_collect()
     minor_collect()
@@ -232,24 +235,13 @@
     
     pr = lib.stm_read_barrier(p)
     assert r != r2
+    # these will fail because pw/pr was
+    # not traced in the last minor_collect,
+    # because they were not registered in
+    # old_objects_to_trace.
     assert getptr(pr, 0) != r
     assert getptr(pr, 0) == r2
 
-    # the following shouldn't be done
-    # because pw was not saved. Just
-    # here to check that pw gets removed
-    # from old_objects_to_trace when not found
-    # on the root stack anymore
-    rawsetptr(pw, 0, q)
-    lib.stm_push_root(q)
-    minor_collect()
-    q2 = lib.stm_pop_root()
-    check_nursery_free(q)
-    pr = lib.stm_read_barrier(p)
-    assert q != q2
-    assert getptr(pr, 0) == q
-    assert getptr(pr, 0) != q2
-
 def test_write_barrier_after_minor_collect_young_to_old():
     p = nalloc_refs(1)
     pw = lib.stm_write_barrier(p)
diff --git a/duhton/listobject.c b/duhton/listobject.c
--- a/duhton/listobject.c
+++ b/duhton/listobject.c
@@ -75,7 +75,7 @@
 
 void _list_append(DuListObject *ob, DuObject *x)
 {
-    _du_write1(ob);
+    _du_read1(ob);
     DuTupleObject *olditems = ob->ob_tuple;
 
     _du_read1(olditems);
@@ -85,6 +85,8 @@
     DuTupleObject *newitems = DuTuple_New(newcount);
     _du_restore3(ob, x, olditems);
 
+    _du_write1(ob);
+
     for (i=0; i<newcount-1; i++)
         newitems->ob_items[i] = olditems->ob_items[i];
     newitems->ob_items[newcount-1] = x;