Bug #75511 [NEW]: fread not free unused buffer.

From: mix5003 at gmail dot com Operating system: * PHP version: Irrelevant Package: Performance problem Bug Type: Bug Bug description:fread not free unused buffer. Description: ------------ When use fread to read multiple small files with large buffer. it may make a memory limit error. i think it becuase php alloc memory equals length that i send to fread and it not trim to actual size of string. so many small string can reach a memory limit. or is it normal behavior? Test script: --------------- <?php ini_set('memory_limit', '256M'); // create file @mkdir('tmp_file'); for($i=0;$i<300;$i++){ file_put_contents("tmp_file/{$i}.txt", $i); } // read file $data = []; for($i=0;$i<300;$i++){ $fp = fopen("tmp_file/{$i}.txt", "r"); $data[$i] = fread($fp, 1024 * 1024); fclose($fp); echo strlen($data[$i])." ".memory_get_usage()."\n"; } Expected result: ---------------- it can run normally. no memory allocate error. Actual result: -------------- Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 1048577 bytes) -- Edit bug report at https://bugs.php.net/bug.php?id=75511&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75511&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75511&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75511&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75511&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75511&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75511&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75511&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75511&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75511&r=support Expected behavior: https://bugs.php.net/fix.php?id=75511&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75511&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75511&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75511&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75511&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75511&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75511&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75511&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75511&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75511&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75511&r=mysqlcfg