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    SubjectRe: [Bug #14141] order 2 page allocation failures (generic)
    On Tue, Oct 20, 2009 at 03:50:12PM +0200, Tobias Oetiker wrote:
    > Hi Mel,
    >
    > Today Mel Gorman wrote:
    >
    > > On Tue, Oct 20, 2009 at 02:58:53PM +0200, Tobias Oetiker wrote:
    > > > you are saing that the problem might be even older ?
    > > >
    > > > we do have 8GB ram and 16 GB swap, so it should not fail to allocate all that
    > > > often
    > > >
    > > > top - 14:58:34 up 19:54, 6 users, load average: 2.09, 1.94, 1.97
    > > > Tasks: 451 total, 1 running, 449 sleeping, 0 stopped, 1 zombie
    > > > Cpu(s): 3.5%us, 15.5%sy, 2.0%ni, 72.2%id, 6.5%wa, 0.1%hi, 0.3%si, 0.0%st
    > > > Mem: 8198504k total, 7599132k used, 599372k free, 1212636k buffers
    > > > Swap: 16777208k total, 83568k used, 16693640k free, 610136k cached
    > > >
    > >
    > > High-order atomic allocations of the type you are trying at that frequency
    > > were always a very long shot. The most likely outcome is that something
    > > has changed that means a burst of allocations trigger an allocation failure
    > > where as before processes would delay long enough for the system not to notice.
    > >
    > > 1. Have MTU settings changed?
    >
    > no not to my knowledge
    >
    > > 2. As order-5 allocations are required to succeed, I'm surprised in a
    > > sense that there are only 5 failures because it implies the machine is
    > > actually recovering and continueing on as normal. Can you think of what
    > > happens in the morning that causes a burst of allocations to occur?
    >
    > the burts occur all day while the machine is in use ... its just
    > that I was writing this at noon so only the morning had passed. So
    > I compared things to the day before ...
    >

    Over the course of a day, how many would you see? By and large, it seems
    that the problem yourself and Frans are similar except his is a lot more
    severe.

    > > 3. Other than the failures, have you noticed any other problems with the
    > > machine or does it continue along happily?
    >
    > The machine seems to be fine.
    >
    > > 4. Does the following patch help by any chance?
    >
    > should I try this on vanilla 2.6.31.4 or ontop of your previous
    > patch?
    >

    Try on top of vanilla 2.6.31.4 first plase and if failures still occur,
    then on top of the previous patch.

    > we are running virtualbox 3.0.8 on this machine, virtualbox is using
    > the physical network interface in bridge mode access the network.
    > Could this have something todo with the problem ?
    >

    I do not know for sure. I'm assuming the configuration is the same on
    both kernels so it's unlikely to be the issue.

    --
    Mel Gorman
    Part-time Phd Student Linux Technology Center
    University of Limerick IBM Dublin Software Lab


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