lkml.org 
[lkml]   [2007]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH 1/1] mm: add dirty_highmem option
    On Thu, 22 Nov 2007 14:42:04 +1100 Bron Gondwana <brong@fastmail.fm> wrote:

    > /*
    > + * free highmem will not be subtracted from the total free memory
    > + * for calculating free ratios if vm_dirty_highmem is true
    > + */
    > +int vm_dirty_highmem;

    One would expect that setting dirty_highmem to true would cause highmem to
    be accounted in dirty-memory calculations. However with this change
    reality is in fact the inverse of that.

    So how about this?

    Documentation/filesystems/proc.txt | 4 ++--
    mm/page-writeback.c | 8 ++++----
    2 files changed, 6 insertions(+), 6 deletions(-)

    diff -puN Documentation/filesystems/proc.txt~mm-add-dirty_highmem-option-fix Documentation/filesystems/proc.txt
    --- a/Documentation/filesystems/proc.txt~mm-add-dirty_highmem-option-fix
    +++ a/Documentation/filesystems/proc.txt
    @@ -1265,8 +1265,8 @@ Contains, as a boolean, a switch to allo
    part of the "available" memory against which the dirty ratios will be
    applied.

    -Setting this to 1 can be useful on 32 bit machines where you want to make
    -random changes within an MMAPed file that is larger than your available
    +Setting this to 0 (false) can be useful on 32 bit machines where you wish to
    +make random changes within an MMAPed file that is larger than your available
    lowmem, however it is potentially dangerous and has serious bounce-buffer
    issues.

    diff -puN mm/page-writeback.c~mm-add-dirty_highmem-option-fix mm/page-writeback.c
    --- a/mm/page-writeback.c~mm-add-dirty_highmem-option-fix
    +++ a/mm/page-writeback.c
    @@ -69,10 +69,10 @@ static inline long sync_writeback_pages(
    int dirty_background_ratio = 5;

    /*
    - * free highmem will not be subtracted from the total free memory
    - * for calculating free ratios if vm_dirty_highmem is true
    + * free highmem will be subtracted from the total free memory for calculating
    + * free ratios if vm_dirty_highmem is true
    */
    -int vm_dirty_highmem;
    +int vm_dirty_highmem = 1;

    /*
    * The generator of dirty data starts writeback at this percentage
    @@ -293,7 +293,7 @@ static unsigned long determine_dirtyable
    x = global_page_state(NR_FREE_PAGES)
    + global_page_state(NR_INACTIVE)
    + global_page_state(NR_ACTIVE);
    - if (!vm_dirty_highmem)
    + if (vm_dirty_highmem)
    x -= highmem_dirtyable_memory(x);
    return x + 1; /* Ensure that we never return 0 */
    }
    _



    (I dropped the already-merged part of your patch)

    (I fixed a build error in kernel/sysctl.c: "one" was defined twice when
    suitable config options were set).

    (It's an unpleasing patch, btw. But it's an unpleasant problem and at least
    this way people can tell us "hey, I did <this> and it started to work")
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-11-27 05:57    [W:0.023 / U:35.656 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site