2.2.17pre10 pauses fixed by Andrea's VM-global-patch-1

From: Chip Salzenberg (chip@valinux.com)
Date: Fri Jul 07 2000 - 23:00:31 EDT

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    While running the "brutal" (-- Alan Cox) Cerberus test suite on a
    2.2.17pre10 kernel, we've been seeing pauses of from five to twenty
    seconds every two minutes or so. As best I can tell from SysReq, when
    the kernel pauses, it's spending time in shrink_mmap(). When pauses
    occur, free RAM is down to about 1M; but it's not a true OOM, since
    there's always lots of free swap space. (Cerberus scales its memory
    usage to avoid filling swap.)

    Good News: The pauses are *almost* completely gone after applying
    Andrea's patch entitled "VM-global-patch-1". The kernel still pauses,
    but only very occasionally, and for no more than two to four seconds;
    and even during the pauses, interactive performance is reasonable.
    According to Jason Collins, creator of Cerberus, it's at least as good
    as any previous 2.2.x when subjected to a Cerberus attack.

    Thanks, Andrea!

    PS: Anyone who wants to stress the VM, I recommend trying Cerberus
        as part of your testing mix. Get it from SourceForge:
          <URL:https://sourceforge.net/projects/va-ctcs/>

    Testing Details:
      Kernel: 2.2.17pre10
      Config: SMP, 2G, NFS root
      Hardware: Intel Lancewood, two P3s, 512M RAM, DAC960 RAID
      Relevant Patches:
                 Dave/Trond/Neil's NFS merge
                 Andrea's VM-global-patch-1
                 Andrea's BIGMEM
                 Solar Designer's security
      Probably Irrelevant Patches:
                 Rik's fair share scheduler (but disabled at the time)
                 Andre Hedrick's IDE
                 Mingo's RAID
                 VA's E820 memory probe
                 Backport of 2.4's AGP driver 

    -- 
Chip Salzenberg              - a.k.a. -              <chip@valinux.com>
"I wanted to play hopscotch with the impenetrable mystery of existence,
    but he stepped in a wormhole and had to go in early."  // MST3K

    -
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