HI,
I have an ubuntu 10.04 with xen kernel 2.6.32.11 as Dom0. xm mem-set
does not seem to have any effect on the HVM domains.
Xen Version : 4.0.1
HVM : Ubuntu 10.04
I have allocated 512MB to dom0 and 2048MB to HVM.
$xm list
Name ID Mem VCPUs State
Time(s)
Domain-0 0 512 1 r-----
358.8
lucid_hvm 1 2048 1 -b----
5.9
The output of free command in the HVM
$free -m
total used free shared buffers cached
Mem: 2012 153 1858 0 24 74
-/+ buffers/cache: 55 1957
Swap: 228 0 228
Using xm mem-set, i tried to allocate 1024MB to the HVM
$xm mem-set lucid_hvm 1024
$xm list
Name ID Mem VCPUs State
Time(s)
Domain-0 0 512 1 r-----
363.1
lucid_hvm 1 1024 1 -b----
7.2
xm list shows that only 1024MB of physical memory is allocated to the HVM.
but, the output of free command in the HVM
$ free -m
total used free shared buffers cached
Mem: 2012 154 1858 0 24 74
-/+ buffers/cache: 55 1957
Swap: 228 0 228
No change in allocated memory. But, xm mem-set works perfectly with paraVM.
I migrated HVM to another machine and checked the amount of data transferred
which is 2048MB.
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On Sat, Sep 25, 2010 at 7:41 AM, cendhu <cendhu@gmail.com> wrote:> HI, > I have an ubuntu 10.04 with xen kernel 2.6.32.11 as Dom0. xm mem-set > does not seem to have any effect on the HVM domains. > Xen Version : 4.0.1 > HVM : Ubuntu 10.04 > I have allocated 512MB to dom0 and 2048MB to HVM. > $xm list > Name ID Mem VCPUs State > Time(s) > Domain-0 0 512 1 r----- > 358.8 > lucid_hvm 1 2048 1 -b---- > 5.9 > The output of free command in the HVM > $free -m > total used free shared buffers cached > Mem: 2012 153 1858 0 24 74 > -/+ buffers/cache: 55 1957 > Swap: 228 0 228 > Using xm mem-set, i tried to allocate 1024MB to the HVM > $xm mem-set lucid_hvm 1024 > $xm list > Name ID Mem VCPUs State > Time(s) > Domain-0 0 512 1 r----- > 363.1 > lucid_hvm 1 1024 1 -b---- > 7.2 > xm list shows that only 1024MB of physical memory is allocated to the HVM. > but, the output of free command in the HVM > $ free -m > total used free shared buffers cached > Mem: 2012 154 1858 0 24 74 > -/+ buffers/cache: 55 1957 > Swap: 228 0 228 > No change in allocated memory. But, xm mem-set works perfectly with paraVM. > I migrated HVM to another machine and checked the amount of data transferred > which is 2048MB. > > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel > >I noticed the same thing a few days ago, I think that the mem-set command should only work if there is a balloon driver running inside the hvm domU which can "take away" the memory from the OS and return it back to Xen, I don''t understand why the command succeeds without a balloon driver but your tests seem to show that it doesn''t actually work as migration moves the original amount of memory. I will investigate this further tomorrow. Andy _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Sun, 26 Sep 2010, Andrew Lyon wrote:> On Sat, Sep 25, 2010 at 7:41 AM, cendhu <cendhu@gmail.com> wrote: > > HI, > > ???? ?? I have an ubuntu 10.04 with xen kernel 2.6.32.11 as Dom0. xm mem-set > > does not seem to have any effect on the HVM domains. > > Xen Version : 4.0.1 > > HVM : Ubuntu 10.04 > > I have allocated 512MB to dom0 and 2048MB to HVM. > > $xm list > > Name ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??ID ?? Mem VCPUs ?? ?? ??State > > Time(s) > > Domain-0 ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? 0 ?? 512 ?? ?? 1 ?? ?? r----- > > ??358.8 > > lucid_hvm ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??1 ??2048 ?? ?? 1 ?? ?? -b---- > > ??5.9 > > The output of free command in the HVM > > $free -m > > ???? ?? ?? ?? ?? ?? total ?? ?? ?? used ?? ?? ?? free ?? ?? shared ?? ??buffers ?? ?? cached > > Mem: ?? ?? ?? ?? ??2012 ?? ?? ?? ??153 ?? ?? ?? 1858 ?? ?? ?? ?? ??0 ?? ?? ?? ?? 24 ?? ?? ?? ?? 74 > > -/+ buffers/cache: ?? ?? ?? ?? 55 ?? ?? ?? 1957 > > Swap: ?? ?? ?? ?? ??228 ?? ?? ?? ?? ??0 ?? ?? ?? ??228 > > Using xm mem-set, i tried to allocate 1024MB to the HVM > > $xm mem-set lucid_hvm 1024 > > $xm list > > Name ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??ID ?? Mem VCPUs ?? ?? ??State > > Time(s) > > Domain-0 ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? 0 ?? 512 ?? ?? 1 ?? ?? r----- > > ??363.1 > > lucid_hvm ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??1 ??1024 ?? ?? 1 ?? ?? -b---- > > ??7.2 > > ??xm list shows that only 1024MB of physical memory is allocated to the HVM. > > but, the output of free command in the HVM > > $ free -m > > ???? ?? ?? ?? ?? ?? total ?? ?? ?? used ?? ?? ?? free ?? ?? shared ?? ??buffers ?? ?? cached > > Mem: ?? ?? ?? ?? ??2012 ?? ?? ?? ??154 ?? ?? ?? 1858 ?? ?? ?? ?? ??0 ?? ?? ?? ?? 24 ?? ?? ?? ?? 74 > > -/+ buffers/cache: ?? ?? ?? ?? 55 ?? ?? ?? 1957 > > Swap: ?? ?? ?? ?? ??228 ?? ?? ?? ?? ??0 ?? ?? ?? ??228 > > No change in allocated memory. But, xm mem-set works perfectly with paraVM. > > I migrated HVM to another machine and checked the amount of data transferred > > which is 2048MB. > > > > > > > > > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xensource.com > > http://lists.xensource.com/xen-devel > > > > > > I noticed the same thing a few days ago, I think that the mem-set > command should only work if there is a balloon driver running inside > the hvm domU which can "take away" the memory from the OS and return > it back to Xen, I don''t understand why the command succeeds without a > balloon driver but your tests seem to show that it doesn''t actually > work as migration moves the original amount of memory. > > I will investigate this further tomorrow. >Yes, xm/xl mem-set only has an effect if there is a balloon driver running in the guest. The command succeeds anyway because all mem-set does is writing a value to xenstore, nothing is guaranteed to happen after that. However if you install a pv on hvm kernel in the guest, you should see the memory being given back to xen, you can download the latest pv on hvm branch from here: git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git 2.6.35-rc5-pvhvm-v7 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel