[lkml]   [2007]   [Mar]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [QUICKLIST 0/4] Arch independent quicklists V2
    > On Tue, 13 Mar 2007 04:17:26 -0700 (PDT) Christoph Lameter <> wrote:
    > On Tue, 13 Mar 2007, Andrew Morton wrote:
    > > > On Tue, 13 Mar 2007 00:13:25 -0700 (PDT) Christoph Lameter <> wrote:
    > > > Page table pages have the characteristics that they are typically zero
    > > > or in a known state when they are freed.
    > >
    > > Well if they're zero then perhaps they should be released to the page
    > > allocator to satisfy the next __GFP_ZERO request. If that request is
    > > for a pagetable page, we break even (except we get to remove
    > > special-case code). If that __GFP_ZERO allocation was or some
    > > application other than for a pagetable, we win.
    > Nope that wont work.
    > 1. We need to support other states of pages other than zeroed.

    What does this mean?

    > 2. Prezeroing does not make much sense if a large portion of the
    > page is being used. Performance is better if the whole page
    > is zeroed directly before use.Prezeroing only makes sense for sparse
    > allocations like the page table pages.

    This is not related to the above discussion.

    > > (Will require some work in the page allocator)
    > > (That work will open the path to using the idle thread to prezero pages)
    > I already tried that 3 years ago and there was *no* benefit for usual
    > users of the a page allocator. The advantage exists only if a small
    > portion of the page is used. F.e. For one cacheline there was a 4x
    > improvement. See lkml archives for prezeroing.

    Unsurprised. Were non-temporal stores tried?
    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: 2007-03-13 12:31    [W:0.021 / U:23.940 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site