Commit f0339db7 authored by Changbin Du's avatar Changbin Du Committed by Jonathan Corbet
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Documentation: x86: convert x86_64/fake-numa-for-cpusets to reST 



This converts the plain text documentation to reStructuredText format and
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Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
Reviewed-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 85a3bd41

Documentation/x86/x86_64/fake-numa-for-cpusets→Documentation/x86/x86_64/fake-numa-for-cpusets.rst

+18 −7
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.. SPDX-License-Identifier: GPL-2.0



=====================

Fake NUMA For CPUSets

=====================



:Author: David Rientjes <rientjes@cs.washington.edu>



Using numa=fake and CPUSets for Resource Management

Written by David Rientjes <rientjes@cs.washington.edu>



This document describes how the numa=fake x86_64 command-line option can be used

in conjunction with cpusets for coarse memory management.  Using this feature,
@@ -20,7 +27,7 @@ you become more familiar with using this combination for resource control, 
you'll determine a better setup to minimize the number of nodes you have to deal

with.



A machine may be split as follows with "numa=fake=4*512," as reported by dmesg:

A machine may be split as follows with "numa=fake=4*512," as reported by dmesg::



	Faking node 0 at 0000000000000000-0000000020000000 (512MB)

	Faking node 1 at 0000000020000000-0000000040000000 (512MB)
@@ -34,7 +41,7 @@ A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: 


Now following the instructions for mounting the cpusets filesystem from

Documentation/cgroup-v1/cpusets.txt, you can assign fake nodes (i.e. contiguous memory

address spaces) to individual cpusets:

address spaces) to individual cpusets::



	[root@xroads /]# mkdir exampleset

	[root@xroads /]# mount -t cpuset none exampleset
@@ -47,7 +54,7 @@ Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for 
memory allocations (1G).



You can now assign tasks to these cpusets to limit the memory resources

available to them according to the fake nodes assigned as mems:

available to them according to the fake nodes assigned as mems::



	[root@xroads /exampleset/ddset]# echo $$ > tasks

	[root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G
@@ -57,9 +64,13 @@ Notice the difference between the system memory usage as reported by 
/proc/meminfo between the restricted cpuset case above and the unrestricted

case (i.e. running the same 'dd' command without assigning it to a fake NUMA

cpuset):

				Unrestricted	Restricted

	MemTotal:		3091900 kB	3091900 kB

	MemFree:		  42113 kB	1513236 kB



	========	============	==========

	Name		Unrestricted	Restricted

	========	============	==========

	MemTotal	3091900 kB	3091900 kB

	MemFree		42113 kB	1513236 kB

	========	============	==========



This allows for coarse memory management for the tasks you assign to particular

cpusets.  Since cpusets can form a hierarchy, you can create some pretty

Documentation/x86/x86_64/index.rst

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@@ -11,3 +11,4 @@ x86_64 Support 
   uefi

   mm

   5level-paging

   fake-numa-for-cpusets