ruby-changes:58620
From: John <ko1@a...>
Date: Fri, 8 Nov 2019 02:31:26 +0900 (JST)
Subject: [ruby-changes:58620] b99833baec (master): Use a monotonically increasing number for object_id
https://git.ruby-lang.org/ruby.git/commit/?id=b99833baec From b99833baec2e567e38758f4fd017c90c7ce57d75 Mon Sep 17 00:00:00 2001 From: John Hawthorn <john@h...> Date: Thu, 31 Oct 2019 17:21:01 -0700 Subject: Use a monotonically increasing number for object_id This changes object_id from being based on the objects location in memory (or a nearby memory location in the case of a conflict) to be based on an always increasing number. This number is a Ruby Integer which allows it to overflow the size of a pointer without issue (very unlikely to happen in real programs especially on 64-bit, but a nice guarantee). This changes obj_to_id_tbl and id_to_obj_tbl to both be maps of Ruby objects to Ruby objects (previously they were Ruby object to C integer) which simplifies updating them after compaction as we can run them through gc_update_table_refs. Co-authored-by: Aaron Patterson <tenderlove@r...> diff --git a/bootstraptest/test_objectspace.rb b/bootstraptest/test_objectspace.rb index 24a1a0c..63a8d99 100644 --- a/bootstraptest/test_objectspace.rb +++ b/bootstraptest/test_objectspace.rb @@ -44,3 +44,12 @@ assert_normal_exit %q{ https://github.com/ruby/ruby/blob/trunk/bootstraptest/test_objectspace.rb#L44 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 cee8f6c..e1bc984 100644 --- a/gc.c +++ b/gc.c @@ -700,6 +700,7 @@ typedef struct rb_objspace { https://github.com/ruby/ruby/blob/trunk/gc.c#L700 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 */ @@ -747,7 +748,6 @@ typedef struct rb_objspace { https://github.com/ruby/ruby/blob/trunk/gc.c#L748 #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; @@ -2846,12 +2846,41 @@ obj_free(rb_objspace_t *objspace, VALUE obj) https://github.com/ruby/ruby/blob/trunk/gc.c#L2846 } } + +#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->id_to_obj_tbl = st_init_numtable(); + objspace->next_object_id = INT2FIX(OBJ_ID_INITIAL); + objspace->id_to_obj_tbl = st_init_table(&object_id_hash_type); objspace->obj_to_id_tbl = st_init_numtable(); #if RGENGC_ESTIMATE_OLDMALLOC @@ -3576,37 +3605,33 @@ id2ref(VALUE obj, VALUE objid) https://github.com/ruby/ruby/blob/trunk/gc.c#L3605 VALUE orig; void *p0; - 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, ptr, &orig)) { - return orig; + 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); + } } - 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 (st_lookup(objspace->id_to_obj_tbl, objid, &orig)) { + return orig; } - if (!is_id_value(objspace, ptr)) { - rb_raise(rb_eRangeError, "%p is not id value", p0); + 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 (!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 @@ -3637,27 +3662,20 @@ cached_object_id(VALUE obj) https://github.com/ruby/ruby/blob/trunk/gc.c#L3662 if (st_lookup(objspace->obj_to_id_tbl, (st_data_t)obj, &id)) { GC_ASSERT(FL_TEST(obj, FL_SEEN_OBJ_ID)); - return nonspecial_obj_id(id); + return id; } else { GC_ASSERT(!FL_TEST(obj, FL_SEEN_OBJ_ID)); - id = obj; - 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); - } - } + 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; } - return nonspecial_obj_id(obj); } static VALUE @@ -5566,6 +5584,10 @@ gc_mark_roots(rb_objspace_t *objspace, const char **categoryp) https://github.com/ruby/ruby/blob/trunk/gc.c#L5584 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"); @@ -7551,18 +7573,6 @@ gc_is_moveable_obj(rb_objspace_t *objspace, VALUE obj) https://github.com/ruby/ruby/blob/trunk/gc.c#L7573 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) { @@ -7604,7 +7614,6 @@ gc_move(rb_objspace_t *objspace, VALUE scan, VALUE free, VALUE moved_list) https://github.com/ruby/ruby/blob/trunk/gc.c#L7614 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 */ @@ -8422,6 +8431,8 @@ gc_update_references(rb_objspace_t * objspace) https://github.com/ruby/ruby/blob/trunk/gc.c#L8431 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_tbl_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); } @@ -8879,7 +8890,6 @@ enum gc_stat_sym { https://github.com/ruby/ruby/blob/trunk/gc.c#L8890 #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, @@ -8955,7 +8965,6 @@ setup_gc_stat_symbols(void) https://github.com/ruby/ruby/blob/trunk/gc.c#L8965 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); @@ -9128,7 +9137,6 @@ gc_stat_internal(VALUE hash_or_sym) https://github.com/ruby/ruby/blob/trunk/gc.c#L9137 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 0f5d418..a5de9fd 100644 --- a/hash.c +++ b/hash.c @@ -273,10 +273,14 @@ rb_objid_hash(st_index_t index) https://g (... truncated) -- ML: ruby-changes@q... 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