[lkml]   [2007]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 10/28] i386: map enough initial memory to create lowmem mappings
    Jeremy Fitzhardinge wrote:
    > head.S creates the very initial pagetable for the kernel. This just
    > maps enough space for the kernel itself, and an allocation bitmap.
    > The amount of mapped memory is rounded up to 4Mbytes, and so this
    > typically ends up mapping 8Mbytes of memory.
    > When booting, pagetable_init() needs to create mappings for all
    > lowmem, and the pagetables for these mappings are allocated from the
    > free pages around the kernel in low memory. If the number of
    > pagetable pages + kernel size exceeds head.S's initial mapping, it
    > will end up faulting on an unmapped page. This will only happen with
    > specific combinations of kernel size and memory size.
    > This patch makes sure that head.S also maps enough space to fit the
    > kernel pagetables as well as the kernel itself. It ends up using an
    > additional two pages of unreclaimable memory.
    > Signed-off-by: Jeremy Fitzhardinge <>
    > Acked-by: "H. Peter Anvin" <>
    > Cc: Andi Kleen <>
    > Cc: Zachary Amsden <>
    > Cc: Chris Wright <>
    > Cc: "Eric W. Biederman" <>
    > Cc: Linus Torvalds <>,

    Is some version of this going in for 2.6.21, or is it not a real problem?
    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: 2007-04-19 22:51    [W:3.074 / U:0.920 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site