On Wednesday, June 6, 2007 1:26 pm Justin Piszcz wrote: > On Wed, 6 Jun 2007, Jesse Barnes wrote: > > 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). > > > > This patch works around the problem by scanning the MTRRs at > > boot and figuring out whether the current end_pfn value (setup > > by early e820 code) goes beyond the highest WB MTRR range, and > > if so, trimming it to match. A fairly obnoxious KERN_WARNING > > is printed too, letting the user know that not all of their > > memory is available due to a likely BIOS bug. > > > > Something similar could be done on i386 if needed, but the boot > > ordering would be slightly different, since the MTRR code on i386 > > depends on the boot_cpu_data structure being setup. > > > > Justin, can you please test and make sure this patch works for > > you too? It'll only work around the problem, but it's better > > than having to do mem= by hand or waiting for a fix from your > > BIOS vendor. > > > > Thanks, > > Jesse > > Against what kernel version does this patch apply?
Um... git as of b4946ffb1860597b187d78d61ac6504177eb0ff8. Sorry I should have updated before spinning the patch (will do now). Jesse - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
