2.4.0-test9-pre4: __alloc_pages(...) try_again:

From: Roger Larsson (roger.larsson@norran.net)
Date: Wed Sep 20 2000 - 16:23:36 EDT

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    Hi,

    Trying to find out why test9-pre4 freezes with mmap002
    I added a counter for try_again loops.

    ... __alloc_pages(...)

            int direct_reclaim = 0;
            unsigned int gfp_mask = zonelist->gfp_mask;
            struct page * page = NULL;
    + int try_again_loops = 0;

    - - -

    + printk("VM: sync kswapd (direct_reclaim: %d) try_again #
    %d\n",
    + direct_reclaim, ++try_again_loops);
                            wakeup_kswapd(1);
                            goto try_again;

    Result was surprising:
      direct_reclaim was 1.
      try_again_loops did never stop increasing (note: it is not static,
      and should restart from zero after each success)

    Why does this happen?
    a) kswapd did not succeed in freeing a suitable page?
    b) __alloc_pages did not succeed in grabbing the page?

    /RogerL 

    --
Home page:
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