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  1. Apr 09, 2009
    • Nathan Lynch's avatar
      sched: do not count frozen tasks toward load · e3c8ca83
      Nathan Lynch authored
      
      
      Freezing tasks via the cgroup freezer causes the load average to climb
      because the freezer's current implementation puts frozen tasks in
      uninterruptible sleep (D state).
      
      Some applications which perform job-scheduling functions consult the
      load average when making decisions.  If a cgroup is frozen, the load
      average does not provide a useful measure of the system's utilization
      to such applications.  This is especially inconvenient if the job
      scheduler employs the cgroup freezer as a mechanism for preempting low
      priority jobs.  Contrast this with using SIGSTOP for the same purpose:
      the stopped tasks do not count toward system load.
      
      Change task_contributes_to_load() to return false if the task is
      frozen.  This results in /proc/loadavg behavior that better meets
      users' expectations.
      
      Signed-off-by: default avatarNathan Lynch <ntl@pobox.com>
      Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Acked-by: default avatarNigel Cunningham <nigel@tuxonice.net>
      Tested-by: default avatarNigel Cunningham <nigel@tuxonice.net>
      Cc: <stable@kernel.org>
      Cc: containers@lists.linux-foundation.org
      Cc: linux-pm@lists.linux-foundation.org
      Cc: Matt Helsley <matthltc@us.ibm.com>
      LKML-Reference: <20090408194512.47a99b95@manatee.lan>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e3c8ca83
  2. Apr 08, 2009
  3. Apr 07, 2009