I know it is an old question! But this time I have different situation.
I'm running php/mysql/apache on OpenSuse. I have set php with 128MB of memory. I don't have any RLimitMEM for apache.
Everything was fine, birds singing, flowers blossoming but once I restarted my apache then bad things happened!
I get PHP Fatal error: out of memory blah blah. All php powered applications that were working fine, now log this error. What happened? I tried memory_limit = 512M without any progress.
I'm confused why all my php files now throw this error except really small scripts. I tried phpinfo() and I really have 128MB of memory there. ( And I know that php apache ini setting is different from standalone php, I configured the correct one! ).
UPDATE:
exact php error samples:
[Mon Jul 25 04:22:25 2011] [error] [client 31.57.122.252] PHP Fatal error: Out of memory (allocated 1048576) (tried to allocate 491520 bytes) in /srv/www/htdocs/phpMyAdmin/libraries/common.inc.php on line 796
[Mon Jul 25 04:26:39 2011] [error] [client 31.57.122.252] PHP Fatal error: Out of memory (allocated 1048576) (tried to allocate 4 bytes) in /srv/sbuta/library/Zend/Config/Ini.php on line 172
[Mon Jul 25 04:27:02 2011] [error] [client 31.57.122.252] PHP Fatal error: Out of memory (allocated 1048576) (tried to allocate 30720 bytes) in /srv/kode/library/Zend/Config/Ini.php on line 132