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    SubjectRe: [PATCH] per-backing dev unplugging #2
    Jens Axboe <> wrote:
    > > I reproduced on 2.6.4-mm1 + backing dev, but 2.6.4-mm1 alone ran fine.
    > > To make a long story short, the swap address space and backing dev don't
    > > define an unplug_io_fn. I was able to reproduce quickly with a swap
    > > heavy workload. The patch below should fix the oops, but probably isn't
    > > correct solution since no queues will get unplugged while waiting on
    > > swap pages.
    > Duh of course, that's pretty silly actually. So the question is if we
    > want to keep assigning a dummy unplug_io_fn (default_backing_dev already
    > has it), or just keep the check. I propose to check like Chris added,
    > and just kill the default_unplug_io_fn() from readahead.c

    I'd be inclined to leave that as-is actually. I'll run with Chris's patch
    temporarily, but we need a real unplug function for swapper_space. Which
    will leave default_backing_dev_info unique.

    I'll do swap_unplug_io_fn(). swap implements a poor-man's raid0. What are
    the locking rules for the unplug function btw? It can sleep, yes?

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      Last update: 2005-03-22 14:01    [W:0.021 / U:53.096 seconds]
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