Bug #75091 [NEW]: The memory taken from opcache.interned_strings_buffer isn't refreshed

From: j3mata at gmail dot com Operating system: CentOS 6 PHP version: 7.0.22 Package: opcache Bug Type: Bug Bug description:The memory taken from opcache.interned_strings_buffer isn't refreshed Description: ------------ Hello, I have came accross this issue after we have recieved random complains for 500ISE errors, which are solved after increasing opcache.interned_strings_buffer value. Through series of tests, it seems that the memory set for opcache.interned_strings_buffer is filled the first time the opcache cache files are created and then if the value set for opcache.interned_strings_buffer is changed, the same amount of memory is requested as the first run. Clearing up the opcache file_cache restarts the above described process. This leads to unexpected behaviour: * if the value is changed to smaller then the initial value -> most likely the site will not load and will return various errors. It seems the cached files are loaded from the opcache code, until the memory is filled ( set by the smaller value ) and just doesn't load the whole application. * if the value is changed to bigger then the initial value -> the opcache uses the same amount of memory for interned_strings_buffer as the initial run. * This is produced in this environment: * shared hosting, where the users applications are kept and loaded from /home/USER/ * opcache file_cache is stored in /home/USER/.opcache * install a application which will take more then 3MB of the interned_strings_buffer memory. Observe with opcache_get_status() the interned_strings_buffer usage ** Here I am using a default WP install, add some big plugings so it has enough modiles/classes to load and somewhere in the code to print out opcache_get_status(). * Set interned_strings_buffer to 4MB and load the application - the interned_strings_buffer memory usage would be somewhere between 3MB and 4MB. * Set interned_strings_buffer to 2MB - it should break ( most often - not able to load some class or 500ISE ). * Clear /home/USER/.opcache/ files. * Set interned_strings_buffer to 2MB and again observe its usage the same way as above - it uses all 2MB ( with a few bytes left free ). * Set interned_strings_buffer to 16MB and again observe its usage - it uses exactly the same amount of memory as the first run ~ 2MB. For the tests I was using opcache.memory_consumption with values 64/128/256. Tested on PHP versions 7.0.22 and 7.1.8. I am not sure this a bug in the opcache, but certainly doesn't seem to be expected behaviour. Regards, Ilian. -- Edit bug report at https://bugs.php.net/bug.php?id=75091&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75091&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75091&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75091&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75091&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75091&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75091&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75091&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75091&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75091&r=support Expected behavior: https://bugs.php.net/fix.php?id=75091&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75091&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75091&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75091&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75091&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75091&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75091&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75091&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75091&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75091&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75091&r=mysqlcfg