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docs/vm: swap_numa.txt: convert to ReST format 

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
hifive-unleashed-5.1
Mike Rapoport 2018-03-21 21:22:40 +02:00 committed by Jonathan Corbet
parent d18edf52f4
commit 5431998233
1 changed files with 32 additions and 21 deletions
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53
Documentation/vm/swap_numa.txt
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@ -1,5 +1,8 @@
.. _swap_numa:
===========================================
Automatically bind swap device to numa node
-------------------------------------------
===========================================
If the system has more than one swap device and swap device has the node
information, we can make use of this information to decide which swap
@ -7,15 +10,16 @@ device to use in get_swap_pages() to get better performance.
How to use this feature
-----------------------
=======================
Swap device has priority and that decides the order of it to be used. To make
use of automatically binding, there is no need to manipulate priority settings
for swap devices. e.g. on a 2 node machine, assume 2 swap devices swapA and
swapB, with swapA attached to node 0 and swapB attached to node 1, are going
to be swapped on. Simply swapping them on by doing:
# swapon /dev/swapA
# swapon /dev/swapB
to be swapped on. Simply swapping them on by doing::
# swapon /dev/swapA
# swapon /dev/swapB
Then node 0 will use the two swap devices in the order of swapA then swapB and
node 1 will use the two swap devices in the order of swapB then swapA. Note
@ -24,32 +28,39 @@ that the order of them being swapped on doesn't matter.
A more complex example on a 4 node machine. Assume 6 swap devices are going to
be swapped on: swapA and swapB are attached to node 0, swapC is attached to
node 1, swapD and swapE are attached to node 2 and swapF is attached to node3.
The way to swap them on is the same as above:
# swapon /dev/swapA
# swapon /dev/swapB
# swapon /dev/swapC
# swapon /dev/swapD
# swapon /dev/swapE
# swapon /dev/swapF
The way to swap them on is the same as above::
# swapon /dev/swapA
# swapon /dev/swapB
# swapon /dev/swapC
# swapon /dev/swapD
# swapon /dev/swapE
# swapon /dev/swapF
Then node 0 will use them in the order of::
swapA/swapB -> swapC -> swapD -> swapE -> swapF
Then node 0 will use them in the order of:
swapA/swapB -> swapC -> swapD -> swapE -> swapF
swapA and swapB will be used in a round robin mode before any other swap device.
node 1 will use them in the order of:
swapC -> swapA -> swapB -> swapD -> swapE -> swapF
node 1 will use them in the order of::
swapC -> swapA -> swapB -> swapD -> swapE -> swapF
node 2 will use them in the order of::
swapD/swapE -> swapA -> swapB -> swapC -> swapF
node 2 will use them in the order of:
swapD/swapE -> swapA -> swapB -> swapC -> swapF
Similaly, swapD and swapE will be used in a round robin mode before any
other swap devices.
node 3 will use them in the order of:
swapF -> swapA -> swapB -> swapC -> swapD -> swapE
node 3 will use them in the order of::
swapF -> swapA -> swapB -> swapC -> swapD -> swapE
Implementation details
----------------------
======================
The current code uses a priority based list, swap_avail_list, to decide
which swap device to use and if multiple swap devices share the same