Bug #60139 [PATCH]: Anonymous functions create cycles not detected by the GC
Edit report at https://bugs.php.net/bug.php?id=60139edit=1
ID: 60139
Patch added by: dmi...@php.net
Reported by:lbarn...@php.net
Summary:Anonymous functions create cycles not detected by
the GC
Status: Assigned
Type: Bug
Package:Performance problem
PHP Version:5.4.0beta2
Assigned To:dmitry
Block user comment: N
Private report: N
New Comment:
The following patch has been added/updated:
Patch Name: gc-closure.diff
Revision: 1320050649
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure.diffrevision=1320050649
Previous Comments:
[2011-10-26 10:36:24] lbarn...@php.net
Description:
In the following Script 1 and Script 2, the created objects are not destructed
until the engine shutdowns because of a reference cycle.
The objects hold a reference to an anonymous function that itself hold a
reference to the object.
It seems that the garbage collector is unable to break the cycle.
Script 3 doesn't leak memory because the anonymous function doesn't hold a
reference to the object.
Test script:
---
# Script 1 (leaks with php5.4)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = function() {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 2 (leaks with php5.3)
?php
class Foo
{
public $x;
public function __construct() {
$self = $this;
$this-x = function() use ($self) {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 3 (no leak)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = get_fun();
}
}
function get_fun() {
return function() {};
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
Expected result:
Memory usage before and after is approximatel the same:
121040
121152
Actual result:
--
Objects are never freed and memory usage increases:
120724
417640
--
Edit this bug report at https://bugs.php.net/bug.php?id=60139edit=1
Bug #60139 [PATCH]: Anonymous functions create cycles not detected by the GC
Edit report at https://bugs.php.net/bug.php?id=60139edit=1
ID: 60139
Patch added by: dmi...@php.net
Reported by:lbarn...@php.net
Summary:Anonymous functions create cycles not detected by
the GC
Status: Assigned
Type: Bug
Package:Performance problem
PHP Version:5.4.0beta2
Assigned To:dmitry
Block user comment: N
Private report: N
New Comment:
The following patch has been added/updated:
Patch Name: gc-closure.diff
Revision: 1320059056
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure.diffrevision=1320059056
Previous Comments:
[2011-10-31 08:44:09] dmi...@php.net
The following patch has been added/updated:
Patch Name: gc-closure.diff
Revision: 1320050649
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure.diffrevision=1320050649
[2011-10-26 10:36:24] lbarn...@php.net
Description:
In the following Script 1 and Script 2, the created objects are not destructed
until the engine shutdowns because of a reference cycle.
The objects hold a reference to an anonymous function that itself hold a
reference to the object.
It seems that the garbage collector is unable to break the cycle.
Script 3 doesn't leak memory because the anonymous function doesn't hold a
reference to the object.
Test script:
---
# Script 1 (leaks with php5.4)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = function() {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 2 (leaks with php5.3)
?php
class Foo
{
public $x;
public function __construct() {
$self = $this;
$this-x = function() use ($self) {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 3 (no leak)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = get_fun();
}
}
function get_fun() {
return function() {};
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
Expected result:
Memory usage before and after is approximatel the same:
121040
121152
Actual result:
--
Objects are never freed and memory usage increases:
120724
417640
--
Edit this bug report at https://bugs.php.net/bug.php?id=60139edit=1
Bug #60139 [PATCH]: Anonymous functions create cycles not detected by the GC
Edit report at https://bugs.php.net/bug.php?id=60139edit=1
ID: 60139
Patch added by: dmi...@php.net
Reported by:lbarn...@php.net
Summary:Anonymous functions create cycles not detected by
the GC
Status: Assigned
Type: Bug
Package:Performance problem
PHP Version:5.4.0beta2
Assigned To:dmitry
Block user comment: N
Private report: N
New Comment:
The following patch has been added/updated:
Patch Name: gc-closure2.diff
Revision: 1320059088
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure2.diffrevision=1320059088
Previous Comments:
[2011-10-31 11:04:17] dmi...@php.net
The following patch has been added/updated:
Patch Name: gc-closure.diff
Revision: 1320059056
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure.diffrevision=1320059056
[2011-10-31 08:44:09] dmi...@php.net
The following patch has been added/updated:
Patch Name: gc-closure.diff
Revision: 1320050649
URL:
https://bugs.php.net/patch-display.php?bug=60139patch=gc-closure.diffrevision=1320050649
[2011-10-26 10:36:24] lbarn...@php.net
Description:
In the following Script 1 and Script 2, the created objects are not destructed
until the engine shutdowns because of a reference cycle.
The objects hold a reference to an anonymous function that itself hold a
reference to the object.
It seems that the garbage collector is unable to break the cycle.
Script 3 doesn't leak memory because the anonymous function doesn't hold a
reference to the object.
Test script:
---
# Script 1 (leaks with php5.4)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = function() {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 2 (leaks with php5.3)
?php
class Foo
{
public $x;
public function __construct() {
$self = $this;
$this-x = function() use ($self) {};
}
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
# Script 3 (no leak)
?php
class Foo
{
public $x;
public function __construct() {
$this-x = get_fun();
}
}
function get_fun() {
return function() {};
}
echo memory_get_usage(), \n;
for ($i = 0; $i 1000; ++$i) {
new Foo;
}
gc_collect_cycles();
echo memory_get_usage(), \n;
?
Expected result:
Memory usage before and after is approximatel the same:
121040
121152
Actual result:
--
Objects are never freed and memory usage increases:
120724
417640
--
Edit this bug report at https://bugs.php.net/bug.php?id=60139edit=1
