Stress test stops

Matthew Dillon dillon at apollo.backplane.com
Mon Mar 17 16:35:52 PDT 2008


:
:Hi,
:
:I followed the stress test guide[1] using "./run.sh all.cfg".
:After some time it suddenly stopped. The last line said something
:like parant 18, scm 9. Since I got no answer on IRC I triggered
:a panic. The results can be found here:
:http://reezer.freeshell.org/dragonfly/
:
:[1] from http://wiki.dragonflybsd.org/index.cgi/HowToStressTest

    Everything is stuck waiting for VM pages to free up, and the pageout
    demon is stuck in wdrain which means it is waiting for in-progress
    writes to the device driver to complete.

    Hmm.  The pageout demon is locked up trying to flush to a MFS
    filesystem (your /tmp) and because of that it can't actually flush
    out any VM pages to a real disk.  The MFS filesystem itself is
    stuck in the page-fault code, resulting in a deadlock.

    There is no easy fix for this at the moment, short of not running
    a stress test on a large MFS filesystem.  The pageout daemon would have
    to be split into a light-weight and heavy-weight version, similar
    to how I split the bufdaemon into two threads.  Alternatively the MFS
    code would need to be redone.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>





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