From 4fccb4834d0455519ff6d7a81551a8dfd360fefa Mon Sep 17 00:00:00 2001 From: Zhu Guihua Date: Mon, 27 Apr 2015 16:47:15 +0800 Subject: docs: update documentation for memory hot unplug Add specification about how to use memory hot unplug, and add a flow diagram to explain memory hot unplug process. Reviewed-by: Igor Mammedov Signed-off-by: Zhu Guihua Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/memory-hotplug.txt | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) (limited to 'docs/memory-hotplug.txt') diff --git a/docs/memory-hotplug.txt b/docs/memory-hotplug.txt index f70571df0c..56bdd0a47b 100644 --- a/docs/memory-hotplug.txt +++ b/docs/memory-hotplug.txt @@ -4,9 +4,7 @@ QEMU memory hotplug This document explains how to use the memory hotplug feature in QEMU, which is present since v2.1.0. -Please, note that memory hotunplug is not supported yet. This means -that you're able to add memory, but you're not able to remove it. -Also, proper guest support is required for memory hotplug to work. +Guest support is required for memory hotplug to work. Basic RAM hotplug ----------------- @@ -74,3 +72,22 @@ comes from regular RAM, 1GB is a 1GB hugepage page and 256MB is from -device pc-dimm,id=dimm1,memdev=mem1 \ -object memory-backend-file,id=mem2,size=256M,mem-path=/mnt/hugepages-2MB \ -device pc-dimm,id=dimm2,memdev=mem2 + + +RAM hot-unplug +--------------- + +In order to be able to hot unplug pc-dimm device, QEMU has to be told the ids +of pc-dimm device and memory backend object. The ids were assigned when you hot +plugged memory. + +Two monitor commands are used to hot unplug memory: + + - "device_del": deletes a front-end pc-dimm device + - "object_del": deletes a memory backend object + +For example, assuming that the pc-dimm device with id "dimm1" exists, and its memory +backend is "mem1", the following commands tries to remove it. + + (qemu) device_del dimm1 + (qemu) object_del mem1 -- cgit v1.2.3