Bro's problems:Out of memory !

    We are intresting in Bro.But when we test it under a simulative network,
it was killed a few minutes by the linux systerm,giving the message of"
Out of memory",while Bro 's message is "internal error:double signal".
    Besides considering the reasons of the traffic speed(about 300 http
connections per sec) and the hardware we used,I wonder wherether there's
some ways that Bro used to control it's memory allocation?
    I notice that in there's something like:

#ifdef malloc
extern "C" {
void* malloc(size_t);
void* realloc(void*, size_t);
void free(void*);
void* operator new(size_t t);
    Is it used to redefine the "new" and "delete" operator?Has that been used in Bro now?
Please give me some suggestions to resolve this.Thanks alot!