[lkml]   [2005]   [Jun]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    Patch in this message
    Subject[PATCH] 2/2 swap token tuning
    It turns out that the original swap token implementation, by Song
    Jiang, only enforced the swap token while the task holding the
    token is handling a page fault. This patch approximates that,
    without adding an additional flag to the mm_struct, by checking
    whether the mm->mmap_sem is held for reading, like the page
    fault code does.

    This patch should have the effect of automatically, and gradually,
    disabling the enforcement of the swap token when there is little
    or no paging going on, and "turning up" the intensity of the swap
    token code the more the task holding the token is thrashing.

    Thanks to Song Jiang for pointing out this aspect of the token
    based thrashing control concept.

    Signed-off-by: Rik van Riel

    --- 2.6.12-swaptoken/mm/thrash.c.orig 2005-06-17 15:48:29.000000000 -0400
    +++ 2.6.12-swaptoken/mm/thrash.c 2005-06-26 17:17:04.000000000 -0400
    @@ -19,7 +19,7 @@ static unsigned long swap_token_check;
    struct mm_struct * swap_token_mm = &init_mm;

    -#define SWAP_TOKEN_TIMEOUT 0
    +#define SWAP_TOKEN_TIMEOUT 300
    * Currently disabled; Needs further code to work at HZ * 300.
    --- 2.6.12-swaptoken/mm/rmap.c.orig 2005-06-26 17:16:50.000000000 -0400
    +++ 2.6.12-swaptoken/mm/rmap.c 2005-06-26 17:13:17.000000000 -0400
    @@ -301,7 +301,11 @@ static int page_referenced_one(struct pa
    if (ptep_clear_flush_young(vma, address, pte))

    - if (mm != current->mm && !ignore_token && has_swap_token(mm))
    + /* Pretend the page is referenced if the task has the
    + swap token and is in the middle of a page fault. */
    + if (mm != current->mm && !ignore_token &&
    + has_swap_token(mm) &&
    + sem_is_read_locked(mm->mmap_sem))

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at
     \ /
      Last update: 2005-06-27 00:42    [W:0.020 / U:1.976 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site