From e58814d150b0652f5e11958b36b85d977fdd0426 Mon Sep 17 00:00:00 2001 From: Aaron Patterson Date: Wed, 6 Nov 2019 15:12:28 -0800 Subject: Revert "Use a monotonically increasing number for object_id" This reverts commit bd2b314a05ae9192b3143e1e678a37c370d8a9ce. --- bootstraptest/test_objectspace.rb | 9 --- gc.c | 138 +++++++++++++++++++------------------- hash.c | 8 +-- test/ruby/test_gc.rb | 8 --- test/ruby/test_gc_compact.rb | 90 +++++++++++++++++++++++++ 5 files changed, 162 insertions(+), 91 deletions(-) diff --git a/bootstraptest/test_objectspace.rb b/bootstraptest/test_objectspace.rb index 63a8d99322..24a1a0ce2c 100644 --- a/bootstraptest/test_objectspace.rb +++ b/bootstraptest/test_objectspace.rb @@ -44,12 +44,3 @@ assert_normal_exit %q{ Thread.new {} end }, '[ruby-core:37858]' - -assert_equal 'ok', %q{ - objects_and_ids = 1000.times.map { o = Object.new; [o, o.object_id] } - objects_and_ids.each { |expected, id| - actual = ObjectSpace._id2ref(id) - raise "expected #{expected.inspect}, got #{actual.inspect}" unless actual.equal?(expected) - } - 'ok' -} diff --git a/gc.c b/gc.c index a92a875c99..5a4f72d9ff 100644 --- a/gc.c +++ b/gc.c @@ -700,7 +700,6 @@ typedef struct rb_objspace { rb_event_flag_t hook_events; size_t total_allocated_objects; - VALUE next_object_id; rb_heap_t eden_heap; rb_heap_t tomb_heap; /* heap for zombies and ghosts */ @@ -748,6 +747,7 @@ typedef struct rb_objspace { #if USE_RGENGC size_t minor_gc_count; size_t major_gc_count; + size_t object_id_collisions; #if RGENGC_PROFILE > 0 size_t total_generated_normal_object_count; size_t total_generated_shady_object_count; @@ -2846,41 +2846,12 @@ obj_free(rb_objspace_t *objspace, VALUE obj) } } - -#define OBJ_ID_INCREMENT (sizeof(RVALUE) / 2) -#define OBJ_ID_INITIAL (OBJ_ID_INCREMENT * 2) - -static int -object_id_cmp(st_data_t x, st_data_t y) -{ - if (RB_TYPE_P(x, T_BIGNUM)) { - return !rb_big_eql(x, y); - } else { - return x != y; - } -} - -static st_index_t -object_id_hash(st_data_t n) -{ - if (RB_TYPE_P(n, T_BIGNUM)) { - return FIX2LONG(rb_big_hash(n)); - } else { - return st_numhash(n); - } -} -static const struct st_hash_type object_id_hash_type = { - object_id_cmp, - object_id_hash, -}; - void Init_heap(void) { rb_objspace_t *objspace = &rb_objspace; - objspace->next_object_id = INT2FIX(OBJ_ID_INITIAL); - objspace->id_to_obj_tbl = st_init_table(&object_id_hash_type); + objspace->id_to_obj_tbl = st_init_numtable(); objspace->obj_to_id_tbl = st_init_numtable(); #if RGENGC_ESTIMATE_OLDMALLOC @@ -3605,33 +3576,37 @@ id2ref(VALUE obj, VALUE objid) VALUE orig; void *p0; - if (FIXNUM_P(objid) || rb_big_size(objid) <= SIZEOF_VOIDP) { - ptr = NUM2PTR(objid); - if (ptr == Qtrue) return Qtrue; - if (ptr == Qfalse) return Qfalse; - if (ptr == Qnil) return Qnil; - if (FIXNUM_P(ptr)) return (VALUE)ptr; - if (FLONUM_P(ptr)) return (VALUE)ptr; - - ptr = obj_id_to_ref(objid); - if ((ptr % sizeof(RVALUE)) == (4 << 2)) { - ID symid = ptr / sizeof(RVALUE); - p0 = (void *)ptr; - if (rb_id2str(symid) == 0) - rb_raise(rb_eRangeError, "%p is not symbol id value", p0); - return ID2SYM(symid); - } - } + ptr = NUM2PTR(objid); + p0 = (void *)ptr; + + if (ptr == Qtrue) return Qtrue; + if (ptr == Qfalse) return Qfalse; + if (ptr == Qnil) return Qnil; + if (FIXNUM_P(ptr)) return (VALUE)ptr; + if (FLONUM_P(ptr)) return (VALUE)ptr; + ptr = obj_id_to_ref(objid); - if (st_lookup(objspace->id_to_obj_tbl, objid, &orig)) { + if (st_lookup(objspace->id_to_obj_tbl, ptr, &orig)) { return orig; } - if (rb_int_ge(objid, objspace->next_object_id)) { - rb_raise(rb_eRangeError, "%+"PRIsVALUE" is not id value", rb_int2str(objid, 10)); - } else { - rb_raise(rb_eRangeError, "%+"PRIsVALUE" is recycled object", rb_int2str(objid, 10)); + if ((ptr % sizeof(RVALUE)) == (4 << 2)) { + ID symid = ptr / sizeof(RVALUE); + if (rb_id2str(symid) == 0) + rb_raise(rb_eRangeError, "%p is not symbol id value", p0); + return ID2SYM(symid); + } + + if (!is_id_value(objspace, ptr)) { + rb_raise(rb_eRangeError, "%p is not id value", p0); + } + if (!is_live_object(objspace, ptr)) { + rb_raise(rb_eRangeError, "%p is recycled object", p0); + } + if (RBASIC(ptr)->klass == 0) { + rb_raise(rb_eRangeError, "%p is internal object", p0); } + return (VALUE)ptr; } static VALUE @@ -3662,20 +3637,27 @@ cached_object_id(VALUE obj) if (st_lookup(objspace->obj_to_id_tbl, (st_data_t)obj, &id)) { GC_ASSERT(FL_TEST(obj, FL_SEEN_OBJ_ID)); - return id; + return nonspecial_obj_id(id); } else { GC_ASSERT(!FL_TEST(obj, FL_SEEN_OBJ_ID)); + id = obj; - id = objspace->next_object_id; - objspace->next_object_id = rb_int_plus(id, INT2FIX(OBJ_ID_INCREMENT)); - - st_insert(objspace->obj_to_id_tbl, (st_data_t)obj, (st_data_t)id); - st_insert(objspace->id_to_obj_tbl, (st_data_t)id, (st_data_t)obj); - FL_SET(obj, FL_SEEN_OBJ_ID); - - return id; + while (1) { + /* id is the object id */ + if (st_is_member(objspace->id_to_obj_tbl, (st_data_t)id)) { + objspace->profile.object_id_collisions++; + id += sizeof(VALUE); + } + else { + st_insert(objspace->obj_to_id_tbl, (st_data_t)obj, (st_data_t)id); + st_insert(objspace->id_to_obj_tbl, (st_data_t)id, (st_data_t)obj); + FL_SET(obj, FL_SEEN_OBJ_ID); + return nonspecial_obj_id(id); + } + } } + return nonspecial_obj_id(obj); } static VALUE @@ -5584,10 +5566,6 @@ gc_mark_roots(rb_objspace_t *objspace, const char **categoryp) MARK_CHECKPOINT("global_tbl"); rb_gc_mark_global_tbl(); - MARK_CHECKPOINT("object_id"); - rb_gc_mark(objspace->next_object_id); - mark_tbl_no_pin(objspace, objspace->obj_to_id_tbl); /* Only mark ids */ - if (stress_to_class) rb_gc_mark(stress_to_class); MARK_CHECKPOINT("finish"); @@ -7573,6 +7551,18 @@ gc_is_moveable_obj(rb_objspace_t *objspace, VALUE obj) return FALSE; } +static int +update_id_to_obj(st_data_t *key, st_data_t *value, st_data_t arg, int exists) +{ + if (exists) { + *value = arg; + return ST_CONTINUE; + } + else { + return ST_STOP; + } +} + static VALUE gc_move(rb_objspace_t *objspace, VALUE scan, VALUE free, VALUE moved_list) { @@ -7606,6 +7596,17 @@ gc_move(rb_objspace_t *objspace, VALUE scan, VALUE free, VALUE moved_list) rb_mv_generic_ivar((VALUE)src, (VALUE)dest); } + VALUE id; + + /* If the source object's object_id has been seen, we need to update + * the object to object id mapping. */ + if (st_lookup(objspace->obj_to_id_tbl, (VALUE)src, &id)) { + gc_report(4, objspace, "Moving object with seen id: %p -> %p\n", (void *)src, (void *)dest); + st_delete(objspace->obj_to_id_tbl, (st_data_t *)&src, 0); + st_insert(objspace->obj_to_id_tbl, (VALUE)dest, id); + st_update(objspace->id_to_obj_tbl, (st_data_t)id, update_id_to_obj, (st_data_t)dest); + } + /* Move the object */ memcpy(dest, src, sizeof(RVALUE)); memset(src, 0, sizeof(RVALUE)); @@ -8427,8 +8428,6 @@ gc_update_references(rb_objspace_t * objspace) rb_transient_heap_update_references(); global_symbols.ids = rb_gc_location(global_symbols.ids); global_symbols.dsymbol_fstr_hash = rb_gc_location(global_symbols.dsymbol_fstr_hash); - gc_update_table_refs(objspace, objspace->obj_to_id_tbl); - gc_update_table_refs(objspace, objspace->id_to_obj_tbl); gc_update_table_refs(objspace, global_symbols.str_sym); gc_update_table_refs(objspace, finalizer_table); } @@ -8886,6 +8885,7 @@ enum gc_stat_sym { #if USE_RGENGC gc_stat_sym_minor_gc_count, gc_stat_sym_major_gc_count, + gc_stat_sym_object_id_collisions, gc_stat_sym_remembered_wb_unprotected_objects, gc_stat_sym_remembered_wb_unprotected_objects_limit, gc_stat_sym_old_objects, @@ -8961,6 +8961,7 @@ setup_gc_stat_symbols(void) S(malloc_increase_bytes_limit); #if USE_RGENGC S(minor_gc_count); + S(object_id_collisions); S(major_gc_count); S(remembered_wb_unprotected_objects); S(remembered_wb_unprotected_objects_limit); @@ -9133,6 +9134,7 @@ gc_stat_internal(VALUE hash_or_sym) SET(malloc_increase_bytes_limit, malloc_limit); #if USE_RGENGC SET(minor_gc_count, objspace->profile.minor_gc_count); + SET(object_id_collisions, objspace->profile.object_id_collisions); SET(major_gc_count, objspace->profile.major_gc_count); SET(remembered_wb_unprotected_objects, objspace->rgengc.uncollectible_wb_unprotected_objects); SET(remembered_wb_unprotected_objects_limit, objspace->rgengc.uncollectible_wb_unprotected_objects_limit); diff --git a/hash.c b/hash.c index a5de9fde07..0f5d418534 100644 --- a/hash.c +++ b/hash.c @@ -273,14 +273,10 @@ rb_objid_hash(st_index_t index) static st_index_t objid_hash(VALUE obj) { - VALUE object_id = rb_obj_id(obj); - if (!FIXNUM_P(object_id)) - object_id = rb_big_hash(object_id); - #if SIZEOF_LONG == SIZEOF_VOIDP - return (st_index_t)st_index_hash((st_index_t)NUM2LONG(object_id)); + return (st_index_t)st_index_hash((st_index_t)NUM2LONG(rb_obj_id(obj))); #elif SIZEOF_LONG_LONG == SIZEOF_VOIDP - return (st_index_t)st_index_hash((st_index_t)NUM2LL(object_id)); + return (st_index_t)st_index_hash((st_index_t)NUM2LL(rb_obj_id(obj))); #endif } diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb index f42e098863..1511ea3011 100644 --- a/test/ruby/test_gc.rb +++ b/test/ruby/test_gc.rb @@ -461,12 +461,4 @@ class TestGc < Test::Unit::TestCase skip "finalizers did not get run" if @result.empty? assert_equal([:c1, :c2], @result) end - - def test_object_ids_never_repeat - GC.start - a = 1000.times.map { Object.new.object_id } - GC.start - b = 1000.times.map { Object.new.object_id } - assert_empty(a & b) - end end diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb index bc26897386..eaffccda08 100644 --- a/test/ruby/test_gc_compact.rb +++ b/test/ruby/test_gc_compact.rb @@ -7,6 +7,13 @@ class TestGCCompact < Test::Unit::TestCase (Fiddle.dlwrap(obj) >> 1) end + def assert_object_ids(list) + same_count = list.find_all { |obj| + memory_location(obj) == obj.object_id + }.count + list.count - same_count + end + def big_list(level = 10) if level > 0 big_list(level - 1) @@ -34,6 +41,89 @@ class TestGCCompact < Test::Unit::TestCase new_object end + def try_to_move_objects + 10.times do + list_of_objects = big_list + + ids = list_of_objects.map(&:object_id) # store id in map + addresses = list_of_objects.map(&self.:memory_location) + + assert_equal ids, addresses + + # All object ids should be equal + assert_equal 0, assert_object_ids(list_of_objects) # should be 0 + + GC.verify_compaction_references(toward: :empty) + + # Some should have moved + id_count = assert_object_ids(list_of_objects) + skip "couldn't get objects to move" if id_count == 0 + assert_operator id_count, :>, 0 + + new_ids = list_of_objects.map(&:object_id) + + # Object ids should not change after compaction + assert_equal ids, new_ids + + new_tenant = find_object_in_recycled_slot(addresses) + return [list_of_objects, addresses, new_tenant] if new_tenant + end + + flunk "Couldn't get objects to move" + end + + def test_find_collided_object + skip "figure out how to guarantee move" + + list_of_objects, addresses, new_tenant = try_to_move_objects + + # This is the object that used to be in new_object's position + loc = memory_location(new_tenant) + assert loc, "should have a memory location" + + if (ENV['TRAVIS'] && RUBY_PLATFORM =~ /darwin/) + skip "tests are failing on Travis osx / Wercker from here" + end + + address_idx = addresses.index(loc) + assert address_idx, "should have an address index" + + previous_tenant = list_of_objects[address_idx] + assert previous_tenant, "should have a previous tenant" + + assert_not_equal previous_tenant.object_id, new_tenant.object_id + + # Should be able to look up object by object_id + assert_equal new_tenant, ObjectSpace._id2ref(new_tenant.object_id) + + # Should be able to look up object by object_id + assert_equal previous_tenant, ObjectSpace._id2ref(previous_tenant.object_id) + + int = (new_tenant.object_id >> 1) + # These two should be the same! but they are not :( + assert_equal int, ObjectSpace._id2ref(int.object_id) + end + + def test_many_collisions + list_of_objects = big_list + ids = list_of_objects.map(&:object_id) + addresses = list_of_objects.map(&self.:memory_location) + + GC.verify_compaction_references(toward: :empty) + + skip "time consuming" + + new_tenants = 10.times.map { + find_object_in_recycled_slot(addresses) + } + + collisions = GC.stat(:object_id_collisions) + skip "couldn't get objects to collide" if collisions == 0 + assert_operator collisions, :>, 0 + ids.clear + new_tenants.clear + end + def test_complex_hash_keys list_of_objects = big_list hash = list_of_objects.hash -- cgit v1.2.3