linux kernel memory management

nyamiaka · 12-12-2015, 10:19 AM

I have read that linux uses paging in its virtual memory model. In this model physical memory and the virtual memory is divided into blocks called pages each with a unique identification number . Processes access physical address indirectly via the page tables its only the kernel (and kernel rou ines) that accesses memory directly.so if a programmer wants to manage the memory of his program as in c language which does not have a garbage collector which memory does one manage the virtual or physical

dugan · 12-12-2015, 10:25 AM

Virtual.

jpollard · 12-12-2015, 01:48 PM

The kernel itself only uses virtual memory - this is to provide the appearance of a contigueous memory range for itself. Then pages are allocations/recovered out of that - and the kernel itself pages data in/out of kernel memory.

berndbausch · 12-12-2015, 07:54 PM

Memory management, that is the mapping of virtual page numbers to physical, is done by the kernel and shielded from processes. There is no programming interface that allows a process to see what physical pages it uses.

The only exception to this rule is that a process can look at kernel memory /dev/kmem and, with the knowledge of kernel data structures, find out what mapping is effective at this point in time.