title: Does malloc only assign space in linear region structure vm_area_t insteading of real memory
body: <p>I read in "Understanding the linux kernel" that when malloc is invokded in user space, the kernel only add an linear region in the vm_area_t structure, insteading of allocating space in memory, which is called ostponing the allocation, and this space allocated in linear region can only be used when page interrupts occur. But if no page can be assigned during the page interrupts, isn't the user cheated when it invokes a malloc?</p>