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  1. Lustre
  2. LU-12651

High kworker CPU usage (osc_grant_work_handler) on IDLE connections

    Details

    • Severity:
      3
    • Rank (Obsolete):
      9223372036854775807

      Description

      We discovered that on our systems with lustre mounted, the kworker is using signifficant amount of CPU.
      perf top shows on an idle system:

       39.44%  [kernel]                  [k] osc_should_shrink_grant
        12.14%  [kernel]                  [k] osc_grant_work_handler
         2.81%  [kernel]                  [k] process_one_work
         2.64%  [kernel]                  [k] __queue_work
         2.56%  [kernel]                  [k] read_tsc
      

      We currently have grant_shrink=0 on this system.

      Looks like doing just du -hs /fs makes the problem go away for some time.
      Also unmounting the filesystem makes the problem go away.
      This is Centos 7.6 system with Lustre 2.12.0

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              • Assignee:
                zam Alexander Zarochentsev
                Reporter:
                Tomaka Jacek Tomaka
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                • Created:
                  Updated:
                  Resolved: