What's the fastest way to consume enough memory to cause the app to be dumped by the OS?

Question

I have an app I call memory eater, which is meant to force other applications to be dumped by the os. It does this by consuming lots of memory over time until it is terminated due to memory pressure. In order to consume memory I basically make copies of JPEG representations of data:

-(IBAction)didTapStartButton:(id)sender{
    int i = 200;
    while (i>0) {
        NSData* data = [UIImagePNGRepresentation(self.image) mutableCopy] ;
        [self.array addObject:[[data description] mutableCopy]];
        [self.array addObject:data];
        i--;
    }
}

This was done entirely with trial and error, and I assume that there is a more straightforward way to consume lots and lots of memory.

Answer 1

You can use malloc() in a loop.

while (1) {
    int *ptr = malloc(4096);
    assert(ptr != NULL);
    *ptr = 0;
}

The *ptr = 0 line is necessary to force the page to be dirty, otherwise you will consume address space instead of memory. The number 4096 ensures that each iteration through the loop will add exactly one dirty page to the address space, since 4096 is the most common page size.