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Description of problem: setmem doesn't take effect for lxc guest. Version-Release number of selected component (if applicable): libvirt-1.2.7-1.el7.x86_64 kernel-3.10.0-145.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1. define and start a lxc guest # virsh -c lxc:// dumpxml helloworld <domain type='lxc'> <name>helloworld</name> <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>102400</currentMemory> <vcpu placement='static'>1</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64'>exe</type> <init>/bin/sh</init> </os> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>destroy</on_crash> <devices> <emulator>/usr/libexec/libvirt_lxc</emulator> <filesystem type='mount' accessmode='passthrough'> <source dir='/'/> <target dir='/'/> </filesystem> <console type='pty' tty='/dev/pts/3'> <source path='/dev/pts/3'/> <target type='lxc' port='0'/> <alias name='console0'/> </console> </devices> <seclabel type='none' model='selinux'/> </domain> 2. check cur_balloon memory size # virsh -c lxc:// dumpxml helloworld | grep -1 memory <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>102400</currentMemory> # virsh memtune helloworld hard_limit : 102400 soft_limit : unlimited swap_hard_limit: unlimited # virsh dommemstat helloworld actual 102400 swap_in 948 rss 948 3. set cur_balloon memory to lower value # virsh -c lxc:// setmem helloworld 1000 # echo $? 0 4. check that value # virsh -c lxc:// dumpxml helloworld | grep -1 memory <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>102400</currentMemory> # virsh memtune helloworld hard_limit : 1000 soft_limit : unlimited swap_hard_limit: unlimited # virsh dommemstat helloworld actual 102400 swap_in 948 rss 948 only the output of memtune is changed as we specified, dumpxml and dommemstat aren't updated. check from cgroup memory controller: # cat /sys/fs/cgroup/memory/machine.slice/machine-lxc\\x2dhelloworld.scope/memory.limit_in_bytes 1024000 This value also didn't change. Expect result: cur_balloon memory is changed to what setmem specified.
Fixed upstream: commit c87f268a369eb0f275781abbf446731f6c23f522 Author: Erik Skultety <eskultet@redhat.com> Date: Fri Oct 24 11:17:20 2014 +0200 lxc: fix setmem effect on a running LXC machine When user calls setmem on a running LXC machine, we do update its cgroup entry, however we neither update domain's runtime XML nor we update our internal structures and this patch fixes it. v1.2.10-98-gc87f268
Verified on libvirt-1.2.15-1.el7.x86_64 Steps 1. prepare a lxc with following xml # virsh -c lxc:/// dumpxml helloworld <domain type='lxc' id='14079'> <name>helloworld</name> <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>1000</currentMemory> <vcpu placement='static' cpuset='1-3'>2</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64'>exe</type> <init>/bin/sh</init> </os> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>destroy</on_crash> <devices> <emulator>/usr/libexec/libvirt_lxc</emulator> <filesystem type='mount' accessmode='passthrough'> <source dir='/'/> <target dir='/'/> </filesystem> <console type='pty' tty='/dev/pts/11'> <source path='/dev/pts/11'/> <target type='lxc' port='0'/> <alias name='console0'/> </console> </devices> <seclabel type='dynamic' model='selinux' relabel='yes'> <label>system_u:system_r:svirt_lxc_net_t:s0:c822,c883</label> <imagelabel>system_u:object_r:svirt_sandbox_file_t:s0:c822,c883</imagelabel> </seclabel> </domain> 2. check mem # virsh -c lxc:// dumpxml helloworld | grep -1 memory <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>102300</currentMemory> # virsh -c lxc:/// memtune helloworld hard_limit : 102400 soft_limit : unlimited swap_hard_limit: unlimited # virsh -c lxc:/// dommemstat helloworld actual 102300 swap_in 564 rss 564 3. set memory # virsh -c lxc:/// setmem helloworld 1000 # virsh -c lxc:// dumpxml helloworld | grep -1 memory <uuid>ed1955f7-4e72-40ae-8265-c193e7436c8a</uuid> <memory unit='KiB'>102400</memory> <currentMemory unit='KiB'>1000</currentMemory> # virsh -c lxc:/// memtune helloworld hard_limit : 1000 soft_limit : unlimited swap_hard_limit: unlimited # virsh -c lxc:/// dommemstat helloworld actual 1000 swap_in 564 rss 564
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2015-2202.html