Messages in this thread | | | Subject | Re: [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information | From | Prakash Sangappa <> | Date | Fri, 4 May 2018 09:27:04 -0700 |
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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. >
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