iPhone after textFieldDoneEditing memory skyrockets

I have a uiview->uiscrollview->textfield and using textFieldDoneEditing method as below, I also made the connection the IB to use it. But I dont use any delegation, it is one of the views in the navigation stack, method works but when I use it and push the uiview t开发者_运维问答o stack, in real device(iPhone4) I see the total used memory increases around 2MB's and it cant be released even I send receivedLowmemory warning.

If I dont edit the textfiled and push the view directly to stack then memory is OK, But even if I only tap on the textfield and close it without editing it then the memory skyrockets after the push. what is the deal with this method? or is it about textField object?

 @property (nonatomic,retain) UITextField *textField;

- (IBAction)textFieldDoneEditing:(id)sender { 
    [sender resignFirstResponder];
}

I read this textfield in my local localNextView method, which I force user to enter input before he press next button;

as I mentioned I dont need to read the value of the field to skyrocket the memory, keyboard open-close is enough. in allocations tool the heap growth can be seen when I open and close the keyboaard