On 5/4/18 7:57 AM, Christopher Lameter wrote:
On Thu, 3 May 2018, prakash.sangappa wrote:
exact numa node from where the pages have been allocated.
Cant you write a small script that scans the information in numa_maps and
then displays the total pages per NUMA node and then a list of which
ranges have how many pages on a particular node?
Don't think we can determine which numa node a given user process
address range has pages from, based on the existing 'numa_maps' file.
Well the information is contained in numa_maps I thought. What is missing?
Currently 'numa_maps' gives a list of numa nodes, memory is allocated per
VMA.
Ex. we get something like from numa_maps.
04000 N0=1,N2=2 kernelpagesize_KB=4
First is the start address of a VMA. This VMA could be much larger then
3 4k pages.
It does not say which address in the VMA has the pages mapped.
reading this file will not be restricted(i.e requiring CAP_SYS_ADMIN).
So a prime motivator here is security restricted access to numa_maps?
No it is the opposite. A regular user should be able to determine
numa node information.
That used to be the case until changes were made to the permissions for
reading numa_maps.
