Apache crashes on heavy load!

Hi!

On a server, an Xserve with 6 GB RAM which is dealing with thousands of small cache files we run Apache with Entropy.ch’s PHP. When on light load everything works, but when thousands log in Apache starts crashing, CPU load goes up to a steady 100% and I see a lot of this in the httpd error-log:

[Wed Aug 11 18:36:45 2004] [notice] child pid 1561 exit signal Alarm clock (14)
*** malloc[1340]: error for object 0xc4000: Can’t deallocate_pages region
*** malloc: vm_allocate(size=20480) failed (error code=4294966995)
*** malloc[1340]: error: Can’t allocate region
*** malloc[1340]: error for object 0x93000: Can’t deallocate_pages region
*** malloc: vm_allocate(size=20480) failed (error code=4294966995)
*** malloc[1340]: error: Can’t allocate region
FATAL: emalloc(): Unable to allocate 16384 bytes

I have, with no luck, tweeked the servers kernel values as follows:
kern.maxproc=4000
kern.maxprocperuid=2048
kern.maxfiles=122880
kern.maxfilesperproc=102400
kern.maxvnodes=337920
net.inet.icmp.icmplim=800

Does anyone know about this error message? Is there some other tweeking that can be made?

Thanks!

/Micke