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    SubjectRe: [PATCH] trim memory not covered by WB MTRRs

    > On some machines, buggy BIOSes don't properly setup WB MTRRs to
    > cover all available RAM, meaning the last few megs (or even gigs)
    > of memory will be marked uncached. Since Linux tends to allocate
    > from high memory addresses first, this causes the machine to be
    > unusably slow as soon as the kernel starts really using memory
    > (i.e. right around init time).

    > + if ((highest_addr >> PAGE_SHIFT) != end_pfn) {
    > + printk(KERN_WARNING "***************\n");
    > + printk(KERN_WARNING "**** WARNING: likely BIOS bug\n");
    > + printk(KERN_WARNING "**** MTRRs don't cover all of "
    > + "memory, trimmed %ld pages\n", end_pfn -
    > + (highest_addr >> PAGE_SHIFT));
    > + printk(KERN_WARNING "***************\n");
    > + end_pfn = highest_addr >> PAGE_SHIFT;

    Missing 4K of memory is not worth 4K of junk in syslog per boot. Can
    you drop the stars and stop shouting?

    (cesky, pictures)
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      Last update: 2007-06-12 16:53    [W:0.020 / U:85.960 seconds]
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