ios4 - iPhone app uses 150 MB memory and still no low memory warning!

Question

I have a questionary application, navigation based which I create and push my tableviews eachtime from a nib. there is no leakage and in instruments live bytes seems around 2-3 MB.

I tested in real device (jailbroken IOS4 iPhone), when I go through deep in the navigation (around 200 page pushes) I can see that memory usage goes upto 150 MB! when I navigate back to root then they are all freed, but isnt this a weird behavior? (around 800 KB for each nib view and no big data or images in it)

The most weird thing is, I put some alerts to didreceivememorywarning and didunloadview methods, and yet didnt receive any memory alerts!

-Why I never get any memory warning and viewDidUnload even the app uses 150 MB and more of memory? -Application works but is this memory usage a problem for Apple store?

Answer 1

Something Funky is going on. Try the following code to check the OS version of how much memory you app uses

-(void) report_memory {
    struct task_basic_info info;
    mach_msg_type_number_t size = sizeof(info);
    kern_return_t kerr = task_info(mach_task_self(),
                                   TASK_BASIC_INFO,
                                   (task_info_t)&info,
                                   &size);
    if( kerr == KERN_SUCCESS ) {
        NSLog(@"Memory in use (in bytes): %u", info.resident_size);
    } else {
        NSLog(@"Error with task_info(): %s", mach_error_string(kerr));
    }


}

You will need to #import "mach/mach.h"

This will tell you how much memory the operating system has granted your app. So if what you are seeing is some weird Instruments behavior, this should shed some light.