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  1. OpenShift Virtualization
  2. CNV-71819

KSM can't enable when the node under memory pressure

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: Major Major
    • CNV v4.21.0
    • CNV v4.21.0
    • CNV Virt-Node
    • None
    • CNV Virt-Node Sprint 279, CNV Virt-Node Sprint 280, CNV Virt-Node Sprint 281
    • None

      Description of problem:

      KSM can't enable when the node under memory pressure

      Version-Release number of selected component (if applicable):

      CNV-v4.20.0.rhel9-70

      How reproducible:

      100%

      Steps to Reproduce:

      1.Enable KSM in HCO by using matchLabels
      spec:
        ksmConfiguration:
          nodeLabelSelector:
            matchLabels:
              label-test-ksm: ""
      2. Add label `label-test-ksm: ""` to one of the node
      
      3. Create 3 vms on that node (by using label selector) 
      
      4. Add annotation to the node to override KSM value:
         kubevirt.io/ksm-free-percent-override: "1.0"
      
      5. Wait when KSM activated on the node

      Actual results:

      $ oc describe node cnv-qe-infra-02.cnvqe3.lab.eng.rdu2.redhat.com | grep ksm
       kubevirt.io/ksm-enabled=true
       kubevirt.io/ksm-free-percent-override: 1.0
       kubevirt.io/ksm-handler-managed: false
      
      sh-5.1# chroot /host
      sh-5.1# cat /sys/kernel/mm/ksm/run
      0

      Expected results:

      1. the value of kubevirt.io/ksm-handler-managed should be "true"
      2. /sys/kernel/mm/ksm/run should be 1

      Additional info:

       

              ffossemo@redhat.com Federico Fossemo
              rh-ee-siwang Sibo Wang
              Denys Shchedrivyi Denys Shchedrivyi
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                Created:
                Updated: