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Changing garbage collector to non-generational.

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This commit is contained in:
Ruben Ayrapetyan
2015-02-18 20:16:35 +03:00
parent d1f6760f01
commit a751ab4f9d
8 changed files with 59 additions and 352 deletions
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jerry-core/ecma/base/ecma-gc.cpp
+50 -310
View File
@@ -37,9 +37,9 @@
/**
* Global lists of objects sorted by generation identifier.
*/
static ecma_object_t *ecma_gc_objects_lists[ ECMA_GC_GEN_COUNT ];
static ecma_object_t *ecma_gc_objects_lists;
static void ecma_gc_mark (ecma_object_t *object_p, ecma_gc_gen_t maximum_gen_to_traverse);
static void ecma_gc_mark (ecma_object_t *object_p);
static void ecma_gc_sweep (ecma_object_t *object_p);
/**
@@ -70,39 +70,6 @@ ecma_gc_set_object_refs (ecma_object_t *object_p, /**< object */
ECMA_OBJECT_GC_REFS_WIDTH);
} /* ecma_gc_set_object_refs */
/**
* Get GC generation of the object.
*/
static ecma_gc_gen_t
ecma_gc_get_object_generation (ecma_object_t *object_p) /**< object */
{
JERRY_ASSERT (object_p != NULL);
ecma_gc_gen_t ret = (ecma_gc_gen_t) jrt_extract_bit_field (object_p->container,
ECMA_OBJECT_GC_GENERATION_POS,
ECMA_OBJECT_GC_GENERATION_WIDTH);
JERRY_ASSERT (ret < ECMA_GC_GEN_COUNT);
return ret;
} /* ecma_gc_get_object_generation */
/**
* Set GC generation of the object.
*/
static void
ecma_gc_set_object_generation (ecma_object_t *object_p, /**< object */
ecma_gc_gen_t generation) /**< generation */
{
JERRY_ASSERT (object_p != NULL);
JERRY_ASSERT (generation < ECMA_GC_GEN_COUNT);
object_p->container = jrt_set_bit_field_value (object_p->container,
generation,
ECMA_OBJECT_GC_GENERATION_POS,
ECMA_OBJECT_GC_GENERATION_WIDTH);
} /* ecma_gc_set_object_generation */
/**
* Get next object in list of objects with same generation.
*/
@@ -167,34 +134,6 @@ ecma_gc_set_object_visited (ecma_object_t *object_p, /**< object */
ECMA_OBJECT_GC_VISITED_WIDTH);
} /* ecma_gc_set_object_visited */
/**
* Get may_ref_younger_objects flag of the object.
*/
static bool
ecma_gc_is_object_may_ref_younger_objects (ecma_object_t *object_p) /**< object */
{
JERRY_ASSERT (object_p != NULL);
return jrt_extract_bit_field (object_p->container,
ECMA_OBJECT_GC_MAY_REF_YOUNGER_OBJECTS_POS,
ECMA_OBJECT_GC_MAY_REF_YOUNGER_OBJECTS_WIDTH);
} /* ecma_gc_is_object_may_ref_younger_objects */
/**
* Set may_ref_younger_objects flag of the object.
*/
static void
ecma_gc_set_object_may_ref_younger_objects (ecma_object_t *object_p, /**< object */
bool is_may_ref_younger_objects) /**< flag value */
{
JERRY_ASSERT (object_p != NULL);
object_p->container = jrt_set_bit_field_value (object_p->container,
is_may_ref_younger_objects,
ECMA_OBJECT_GC_MAY_REF_YOUNGER_OBJECTS_POS,
ECMA_OBJECT_GC_MAY_REF_YOUNGER_OBJECTS_WIDTH);
} /* ecma_gc_set_object_may_ref_younger_objects */
/**
* Initialize GC information for the object
*/
@@ -203,14 +142,11 @@ ecma_init_gc_info (ecma_object_t *object_p) /**< object */
{
ecma_gc_set_object_refs (object_p, 1);
ecma_gc_set_object_generation (object_p, ECMA_GC_GEN_0);
ecma_gc_set_object_next (object_p, ecma_gc_objects_lists[ ECMA_GC_GEN_0 ]);
ecma_gc_objects_lists[ ECMA_GC_GEN_0 ] = object_p;
ecma_gc_set_object_next (object_p, ecma_gc_objects_lists);
ecma_gc_objects_lists = object_p;
/* Should be set to false at the beginning of garbage collection */
ecma_gc_set_object_visited (object_p, true);
ecma_gc_set_object_may_ref_younger_objects (object_p, false);
} /* ecma_init_gc_info */
/**
@@ -232,66 +168,25 @@ ecma_deref_object (ecma_object_t *object_p) /**< object */
ecma_gc_set_object_refs (object_p, ecma_gc_get_object_refs (object_p) - 1);
} /* ecma_deref_object */
/**
* Set may_ref_younger_objects of specified object to true,
* if value is object-value and it's object's generation
* is less than generation of object specified by obj_p.
*/
void
ecma_gc_update_may_ref_younger_object_flag_by_value (ecma_object_t *obj_p, /**< object */
const ecma_value_t& value) /**< value */
{
if (!ecma_is_value_object (value))
{
return;
}
ecma_object_t *ref_obj_p = ecma_get_object_from_value (value);
JERRY_ASSERT(ref_obj_p != NULL);
ecma_gc_update_may_ref_younger_object_flag_by_object (obj_p, ref_obj_p);
} /* ecma_gc_update_may_ref_younger_object_flag_by_value */
void
ecma_gc_update_may_ref_younger_object_flag_by_object (ecma_object_t *obj_p, /**< object */
ecma_object_t *ref_obj_p) /**< referenced object
or NULL */
{
if (ref_obj_p == NULL)
{
return;
}
if (ecma_gc_get_object_generation (ref_obj_p) < ecma_gc_get_object_generation (obj_p))
{
ecma_gc_set_object_may_ref_younger_objects (obj_p, true);
}
} /* ecma_gc_update_may_ref_younger_object_flag_by_object */
/**
* Initialize garbage collector
*/
void
ecma_gc_init (void)
{
memset (ecma_gc_objects_lists, 0, sizeof (ecma_gc_objects_lists));
ecma_gc_objects_lists = NULL;
} /* ecma_gc_init */
/**
* Mark objects as visited starting from specified object as root
* if referenced object's generation is less or equal to maximum_gen_to_traverse.
*/
void
ecma_gc_mark (ecma_object_t *object_p, /**< start object */
ecma_gc_gen_t maximum_gen_to_traverse) /**< start recursive traverse
if referenced object generation
is less or equal to maximum_gen_to_traverse */
ecma_gc_mark (ecma_object_t *object_p) /**< start object */
{
JERRY_ASSERT(object_p != NULL);
ecma_gc_set_object_visited (object_p, true);
bool does_ref_a_younger_object = false;
bool traverse_properties = true;
if (ecma_is_lexical_environment (object_p))
@@ -299,34 +194,18 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
ecma_object_t *lex_env_p = ecma_get_lex_env_outer_reference (object_p);
if (lex_env_p != NULL)
{
if (ecma_gc_get_object_generation (lex_env_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (lex_env_p))
{
if (!ecma_gc_is_object_visited (lex_env_p))
{
ecma_gc_mark (lex_env_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (lex_env_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (lex_env_p);
}
}
if (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_OBJECTBOUND)
{
ecma_object_t *binding_object_p = ecma_get_lex_env_binding_object (object_p);
if (ecma_gc_get_object_generation (binding_object_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (binding_object_p))
{
if (!ecma_gc_is_object_visited (binding_object_p))
{
ecma_gc_mark (binding_object_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (binding_object_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (binding_object_p);
}
traverse_properties = false;
@@ -337,17 +216,9 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
ecma_object_t *proto_p = ecma_get_object_prototype (object_p);
if (proto_p != NULL)
{
if (ecma_gc_get_object_generation (proto_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (proto_p))
{
if (!ecma_gc_is_object_visited (proto_p))
{
ecma_gc_mark (proto_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (proto_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (proto_p);
}
}
}
@@ -371,17 +242,9 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
{
ecma_object_t *value_obj_p = ecma_get_object_from_value (value);
if (ecma_gc_get_object_generation (value_obj_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (value_obj_p))
{
if (!ecma_gc_is_object_visited (value_obj_p))
{
ecma_gc_mark (value_obj_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (value_obj_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (value_obj_p);
}
}
@@ -395,33 +258,17 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
if (getter_obj_p != NULL)
{
if (ecma_gc_get_object_generation (getter_obj_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (getter_obj_p))
{
if (!ecma_gc_is_object_visited (getter_obj_p))
{
ecma_gc_mark (getter_obj_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (getter_obj_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (getter_obj_p);
}
}
if (setter_obj_p != NULL)
{
if (ecma_gc_get_object_generation (setter_obj_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (setter_obj_p))
{
if (!ecma_gc_is_object_visited (setter_obj_p))
{
ecma_gc_mark (setter_obj_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (setter_obj_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (setter_obj_p);
}
}
@@ -470,17 +317,9 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
{
ecma_object_t *obj_p = ECMA_GET_NON_NULL_POINTER(ecma_object_t, property_value);
if (ecma_gc_get_object_generation (obj_p) <= maximum_gen_to_traverse)
if (!ecma_gc_is_object_visited (obj_p))
{
if (!ecma_gc_is_object_visited (obj_p))
{
ecma_gc_mark (obj_p, ECMA_GC_GEN_COUNT);
}
}
if (ecma_gc_get_object_generation (obj_p) < ecma_gc_get_object_generation (object_p))
{
does_ref_a_younger_object = true;
ecma_gc_mark (obj_p);
}
break;
@@ -492,11 +331,6 @@ ecma_gc_mark (ecma_object_t *object_p, /**< start object */
}
}
}
if (!does_ref_a_younger_object)
{
ecma_gc_set_object_may_ref_younger_objects (object_p, false);
}
} /* ecma_gc_mark */
/**
@@ -530,34 +364,26 @@ ecma_gc_sweep (ecma_object_t *object_p) /**< object to free */
* Run garbage collecting
*/
void
ecma_gc_run (ecma_gc_gen_t max_gen_to_collect) /**< maximum generation to run collection on */
ecma_gc_run (void)
{
JERRY_ASSERT(max_gen_to_collect < ECMA_GC_GEN_COUNT);
/* clearing visited flags for all objects of generations to be processed */
for (ecma_gc_gen_t gen_id = ECMA_GC_GEN_0; gen_id <= max_gen_to_collect; gen_id = (ecma_gc_gen_t) (gen_id + 1))
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists;
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
{
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists[ gen_id ];
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
{
ecma_gc_set_object_visited (obj_iter_p, false);
}
ecma_gc_set_object_visited (obj_iter_p, false);
}
/* if some object is referenced from stack or globals (i.e. it is root),
* start recursive marking traverse from the object */
for (ecma_gc_gen_t gen_id = ECMA_GC_GEN_0; gen_id <= max_gen_to_collect; gen_id = (ecma_gc_gen_t) (gen_id + 1))
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists;
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
{
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists[ gen_id ];
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
if (ecma_gc_get_object_refs (obj_iter_p) > 0
&& !ecma_gc_is_object_visited (obj_iter_p))
{
if (ecma_gc_get_object_refs (obj_iter_p) > 0
&& !ecma_gc_is_object_visited (obj_iter_p))
{
ecma_gc_mark (obj_iter_p, ECMA_GC_GEN_COUNT);
}
ecma_gc_mark (obj_iter_p);
}
}
@@ -577,119 +403,36 @@ ecma_gc_run (ecma_gc_gen_t max_gen_to_collect) /**< maximum generation to run co
if (!ecma_gc_is_object_visited (obj_p))
{
ecma_gc_mark (obj_p, ECMA_GC_GEN_COUNT);
ecma_gc_mark (obj_p);
}
}
}
}
/* if some object from generations that are not processed during current session may reference
* younger generations, start recursive marking traverse from the object, but one the first level
* consider only references to object of at most max_gen_to_collect generation */
for (ecma_gc_gen_t gen_id = (ecma_gc_gen_t) (max_gen_to_collect + 1);
gen_id < ECMA_GC_GEN_COUNT;
gen_id = (ecma_gc_gen_t) (gen_id + 1))
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists, *obj_prev_p = NULL, *obj_next_p;
obj_iter_p != NULL;
obj_iter_p = obj_next_p)
{
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists[ gen_id ];
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
obj_next_p = ecma_gc_get_object_next (obj_iter_p);
if (!ecma_gc_is_object_visited (obj_iter_p))
{
if (ecma_gc_is_object_may_ref_younger_objects (obj_iter_p))
ecma_gc_sweep (obj_iter_p);
if (likely (obj_prev_p != NULL))
{
ecma_gc_mark (obj_iter_p, max_gen_to_collect);
}
#ifndef JERRY_NDEBUG
else if (gen_id > ECMA_GC_GEN_0)
{
ecma_gc_set_object_may_ref_younger_objects (obj_iter_p, true);
ecma_gc_mark (obj_iter_p, (ecma_gc_gen_t) (gen_id - 1));
JERRY_ASSERT (!ecma_gc_is_object_may_ref_younger_objects (obj_iter_p));
}
#endif /* !JERRY_NDEBUG */
}
}
JERRY_ASSERT (max_gen_to_collect <= ECMA_GC_GEN_COUNT);
ecma_object_t *gen_last_obj_p[ ECMA_GC_GEN_COUNT ];
#ifndef JERRY_NDEBUG
memset (gen_last_obj_p, 0, sizeof (gen_last_obj_p));
#endif /* !JERRY_NDEBUG */
for (ecma_gc_gen_t gen_id = ECMA_GC_GEN_0; gen_id <= max_gen_to_collect; gen_id = (ecma_gc_gen_t) (gen_id + 1))
{
ecma_object_t *obj_prev_p = NULL;
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists[ gen_id ],
*obj_next_p;
obj_iter_p != NULL;
obj_iter_p = obj_next_p)
{
obj_next_p = ecma_gc_get_object_next (obj_iter_p);
if (!ecma_gc_is_object_visited (obj_iter_p))
{
ecma_gc_sweep (obj_iter_p);
if (likely (obj_prev_p != NULL))
{
ecma_gc_set_object_next (obj_prev_p, obj_next_p);
}
else
{
ecma_gc_objects_lists[ gen_id ] = obj_next_p;
}
ecma_gc_set_object_next (obj_prev_p, obj_next_p);
}
else
{
obj_prev_p = obj_iter_p;
if (ecma_gc_get_object_generation (obj_iter_p) != ECMA_GC_GEN_COUNT - 1)
{
/* the object will be promoted to next generation */
ecma_gc_set_object_generation (obj_iter_p, (ecma_gc_gen_t) (ecma_gc_get_object_generation (obj_iter_p) + 1));
}
ecma_gc_objects_lists = obj_next_p;
}
}
gen_last_obj_p[ gen_id ] = obj_prev_p;
}
ecma_gc_gen_t gen_to_promote = max_gen_to_collect;
if (unlikely (gen_to_promote == ECMA_GC_GEN_COUNT - 1))
{
/* not promoting last generation */
gen_to_promote = (ecma_gc_gen_t) (gen_to_promote - 1);
}
/* promoting to next generation */
if (gen_last_obj_p[ gen_to_promote ] != NULL)
{
ecma_gc_set_object_next (gen_last_obj_p [gen_to_promote], ecma_gc_objects_lists[ gen_to_promote + 1 ]);
ecma_gc_objects_lists[ gen_to_promote + 1 ] = ecma_gc_objects_lists[ gen_to_promote ];
ecma_gc_objects_lists[ gen_to_promote ] = NULL;
}
for (int32_t gen_id = (int32_t)gen_to_promote - 1;
gen_id >= 0;
gen_id--)
{
ecma_gc_objects_lists[ gen_id + 1 ] = ecma_gc_objects_lists[ gen_id ];
ecma_gc_objects_lists[ gen_id ] = NULL;
}
#ifndef JERRY_NDEBUG
for (ecma_gc_gen_t gen_id = ECMA_GC_GEN_0;
gen_id < ECMA_GC_GEN_COUNT;
gen_id = (ecma_gc_gen_t) (gen_id + 1))
{
for (ecma_object_t *obj_iter_p = ecma_gc_objects_lists[ gen_id ];
obj_iter_p != NULL;
obj_iter_p = ecma_gc_get_object_next (obj_iter_p))
else
{
JERRY_ASSERT(ecma_gc_get_object_generation (obj_iter_p) == gen_id);
obj_prev_p = obj_iter_p;
}
}
#endif /* !JERRY_NDEBUG */
} /* ecma_gc_run */
/**
@@ -701,15 +444,12 @@ ecma_try_to_give_back_some_memory (mem_try_give_memory_back_severity_t severity)
{
if (severity == MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_LOW)
{
ecma_gc_run (ECMA_GC_GEN_0);
ecma_gc_run ();
}
else if (severity == MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_MEDIUM)
else if (severity == MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_MEDIUM
|| severity == MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_HIGH)
{
ecma_gc_run (ECMA_GC_GEN_1);
}
else if (severity == MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_HIGH)
{
ecma_gc_run (ECMA_GC_GEN_2);
/* we have already done simple GC as requests come in ascending severity order */
}
else
{
@@ -718,7 +458,7 @@ ecma_try_to_give_back_some_memory (mem_try_give_memory_back_severity_t severity)
/* Freeing as much memory as we currently can */
ecma_lcache_invalidate_all ();
ecma_gc_run ((ecma_gc_gen_t) (ECMA_GC_GEN_COUNT - 1));
ecma_gc_run ();
}
} /* ecma_try_to_give_back_some_memory */