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    SubjectRe: Memory overcommit
    On Fri, 30 Oct 2009, KAMEZAWA Hiroyuki wrote:

    > > > - The kernel can't know the program is bad or not. just guess it.
    > >
    > > Totally irrelevant, given your fourth point about /proc/pid/oom_adj. We
    > > can tell the kernel what we'd like the oom killer behavior should be if
    > > the situation arises.
    > >
    > My point is that the server cannot distinguish memory leak from intentional
    > memory usage. No other than that.

    That's a different point. Today, we can influence the badness score of
    any user thread to prioritize oom killing from userspace and that can be
    done regardless of whether there's a memory leaker, a fork bomber, etc.
    The priority based oom killing is important to production scenarios and
    cannot be replaced by a heuristic that works everytime if it cannot be
    influenced by userspace.

    A spike in memory consumption when a process is initially forked would be
    defined as a memory leaker in your quiet_time model.

    > In this summer, at lunch with a daily linux user, I was said
    > "you, enterprise guys, don't consider desktop or laptop problem at all."
    > yes, I use only servers. My customer uses server, too. My first priority
    > is always on server users.
    > But, for this time, I wrote reply to Vedran and try to fix desktop problem.
    > Even if current logic works well for servers, "KDE/GNOME is killed" problem
    > seems to be serious. And this may be a problem for EMBEDED people, I guess.

    You argued before that the problem wasn't specific to X (after I said you
    could protect it very trivially with /proc/pid/oom_adj set to
    OOM_DISABLE), but that's now your reasoning for rewriting the oom killer

    > I can say the same thing to total_vm size. total_vm size doesn't include any
    > good information for oom situation. And tweaking based on that not-useful
    > parameter will make things worse.

    Tweaking on the heuristic will probably make it more convoluted and
    overall worse, I agree. But it's a more stable baseline than rss from
    which we can set oom killing priorities from userspace.

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      Last update: 2009-11-03 21:53    [W:0.023 / U:88.128 seconds]
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