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From: Prakash Sangappa <prakash.sangappa@oracle.com>
To: Christopher Lameter <cl@linux.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-api@vger.kernel.org, akpm@linux-foundation.org,
	mhocko@suse.com, kirill.shutemov@linux.intel.com,
	n-horiguchi@ah.jp.nec.com, drepper@gmail.com,
	rientjes@google.com
Subject: Re: [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information
Date: Fri, 4 May 2018 09:27:04 -0700	[thread overview]
Message-ID: <98e34010-d55a-5f2d-7d98-cba424de2e74@oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1805040955550.10847@nuc-kabylake>



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.
>


WARNING: multiple messages have this Message-ID (diff)
From: Prakash Sangappa <prakash.sangappa@oracle.com>
To: Christopher Lameter <cl@linux.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-api@vger.kernel.org, akpm@linux-foundation.org,
	mhocko@suse.com, kirill.shutemov@linux.intel.com,
	n-horiguchi@ah.jp.nec.com, drepper@gmail.com,
	rientjes@google.com
Subject: Re: [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information
Date: Fri, 4 May 2018 09:27:04 -0700	[thread overview]
Message-ID: <98e34010-d55a-5f2d-7d98-cba424de2e74@oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1805040955550.10847@nuc-kabylake>



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.

04000A  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.
>

  reply	other threads:[~2018-05-04 16:28 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-02  5:58 [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information Prakash Sangappa
2018-05-02 21:33 ` Andrew Morton
2018-05-02 22:28   ` Dave Hansen
2018-05-02 23:17     ` prakash.sangappa
2018-05-03  8:46     ` Anshuman Khandual
2018-05-03 22:27       ` prakash.sangappa
2018-05-03 22:26         ` Dave Hansen
2018-05-07 23:22           ` prakash.sangappa
2018-05-08  0:05             ` Dave Hansen
2018-05-08  1:16               ` prakash.sangappa
2018-05-09 23:31                 ` Dave Hansen
2018-09-12 20:42                   ` prakash.sangappa
2018-09-12 20:57                     ` prakash.sangappa
2018-09-14  1:33                     ` Jann Horn
2018-09-14  6:21                       ` Michal Hocko
2018-09-14 12:49                         ` Jann Horn
2018-09-14 13:49                           ` Michal Hocko
2018-09-14 18:07                           ` Prakash Sangappa
2018-09-14 18:14                             ` Jann Horn
2018-05-02 23:43   ` prakash.sangappa
2018-05-03  8:57     ` Michal Hocko
2018-05-03 22:37       ` prakash.sangappa
2018-05-04 11:10         ` Michal Hocko
2018-05-03 18:03 ` Christopher Lameter
2018-05-03 22:39   ` prakash.sangappa
2018-05-04 11:12     ` Michal Hocko
2018-05-04 16:18       ` Prakash Sangappa
2018-05-04 16:18         ` Prakash Sangappa
2018-05-10  7:42         ` Michal Hocko
2018-05-10  7:42           ` Michal Hocko
2018-05-10 16:00           ` Prakash Sangappa
2018-05-10 16:00             ` Prakash Sangappa
2018-05-11  6:39             ` Michal Hocko
2018-05-04 14:57     ` Christopher Lameter
2018-05-04 16:27       ` Prakash Sangappa [this message]
2018-05-04 16:27         ` Prakash Sangappa
2018-05-07 14:47         ` Christopher Lameter
2018-05-07 14:47           ` Christopher Lameter
2018-05-07 22:50           ` prakash.sangappa
2018-05-08 12:53             ` Christopher Lameter
2018-09-12 23:02 Alexey Dobriyan
2018-09-13 22:17 ` prakash.sangappa

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