lkml.org 
[lkml]   [2000]   [Mar]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: HIGH MEMORY access
    Ingo Molnar wrote:
    >
    > On Fri, 3 Mar 2000, Manfred Spraul wrote:
    >
    > > Now I'm confused: I thought that ioremap() should be used for reserved
    > > memory, and kmap() for normal memory (e820: ram) with
    > > page->virtual==NULL.
    >
    > well you can use kmap() for anything, not just high memory.

    kmap() assumes that a "struct page" exists.

    It's not guaranteed that a "struct page" exists for reserved memory:
    this could happen if you boot with "mem=32M", or if the ACPI tables are
    the last element in the e820 map:

    * max_pfn is set to the end if the last usable block.
    * then the ACPI tables follow --> they are behind max_pfn --> behind the
    end of mem_map.

    Not everyone has 8 GB memory :-(

    --
    Manfred

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:56    [W:0.020 / U:178.956 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site