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    SubjectRe: [PATCH 2/2] oom: give bonus to frozen processes
    On Mon, 26 Sep 2011, Michal Hocko wrote:

    > Let's try it with a heuristic change first. If you really do not like
    > it, we can move to oom_scode_adj. I like the heuristic change little bit
    > more because it is at the same place as the root bonus.

    The problem with the bonus is that, as mentioned previously, it doesn't
    protect against ANYTHING for the case you're trying to fix. This won't
    panic the machine because all killable threads are guaranteed to have a
    non-zero badness score, but it's a very valid configuration to have either

    - all eligible threads (system-wide, shared cpuset, shared mempolicy
    nodes) are frozen, or

    - all eligible frozen threads use <5% of memory whereas all other
    eligible killable threads use 1% of available memory.

    and that means the oom killer will repeatedly select those threads and the
    livelock still exists unless you can guarantee that they are successfully
    thawed, that thawing them in all situations is safe, and that once thawed
    they will make a timely exit.

    Additionally, I don't think biasing against frozen tasks makes sense from
    a heusritic standpoint of the oom killer. Why would we want give
    non-frozen tasks that are actually getting work done a preference over a
    task that is frozen and doing absolutely nothing? It seems like that's
    backwards and that we'd actually prefer killing the task doing nothing so
    it can free its memory.

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      Last update: 2011-09-26 11:05    [W:0.020 / U:8.880 seconds]
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