lkml.org 
[lkml]   [2007]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch] cache pipe buf page address for non-highmem arch
    On Fri, Mar 23, 2007 at 10:14:52AM +0000, Christoph Hellwig wrote:
    > I think you're fixing the symptom here and not the cause. If calculating
    > the virtual address of a page is so expensive on your setup it should
    > define WANT_PAGE_VIRTUAL and we should always cache the virtual address
    > in struct page. There's a lot more code, epecially in filesystems that's
    > rather upset about a slow page_address.

    Andi shot that down when I brought it up a while ago, as it does show
    up in profiles for networking and other code paths. His argument is that
    the loss of memory is excessive. Personally, I think the benefits of a
    64 byte struct page on x86-64 outweigh the memory loss, as it means page
    index to address translations are a simple shift.

    -ben
    --
    "Time is of no importance, Mr. President, only life is important."
    Don't Email: <zyntrop@kvack.org>.
    -
    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: 2007-03-24 02:43    [W:0.018 / U:30.944 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site