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Posted v5 a few days ago:
http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg00547.html
This is very likely to be the final version. It's also important to note that the QMP command from the RFC series (comment 4) has been dropped. We're only going to have command-line support for this (-machine mem-merge=on|off).
Verify this bug with qemu-kvm-1.5.3-10.el7.x86_64 and 3.10.0-37.el7.x86_64
steps:
Test Scenario-1
In host
1.echo 1 > /sys/kernel/mm/ksm/run
2.echo 50 > /sys/kernel/mm/ksm/sleep_millisecs
3.echo 5000 > /sys/kernel/mm/ksm/pages_to_scan
4.Boot two RHEL7.0 guests with "-machine mem-merge=on"
In guest
1.swapoff -a(disable swap)
2.mount -f tmpfs none /mnt
3. dd if=/dev/zero of=/mnt/zero
result:
This pages_sharing continues to rise(1444~1348592)
cat /sys/kernel/mm/ksm/pages_sharing
1348592
Test Scenario-2
Use the same test steps as Scenario1.
If booting two guests with -machine mem-merge=off.
result:
This pages_sharing is constant(no change)
cat /sys/kernel/mm/ksm/pages_sharing
1444
Test scanrio-3
Booting the first guest with -machine mem-merge=off
Booting the second guest with -machine mem-merge=on
result:
This pages_sharing is constant(no change) after booting the first guest and run dd command line in guest.
cat /sys/kernel/mm/ksm/pages_sharing
1444
This pages_sharing continues to rise(1444~59363) when booting the second guest.
cat /sys/kernel/mm/ksm/pages_sharing
59363
Base on test result above, qemu-kvm option "-machine mem-merge=on/off" can enable/disable ksm per guest. So this bug is fixed.
This request was resolved in Red Hat Enterprise Linux 7.0.
Contact your manager or support representative in case you have further questions about the request.