Messages in this thread | | | Date | Mon, 10 Sep 2012 11:54:56 +0800 | From | "zhenzhong.duan" <> | Subject | Re: [RFC] x86: mtrr: Constrain WB MTRR to max phys mem prior to cleanup |
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于 2012-09-08 02:40, H. Peter Anvin 写道: > On 09/07/2012 10:44 AM, Peter Hurley wrote: > \> >> diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c >> b/arch/x86/kernel/cpu/mtrr/cleanup.c > > I really don't like it as it introduces yet another user of max_pfn, > which should be going away. Furthermore, the better question is what > remaining needs there are for MTRR cleanup; historically the reason > was that it prevented the display from being mapped WC via MTRR due to > the MTRR conflict resolution rules favoring UC. For a large memory system, mtrr_cleanup offten fail in most case. Even if it succeed, it often occupy all of MTRR entrys. How was display mapped as WC in above case? Why did bios give a lot of space then real mem, for hotplug? > > However, the right way to fix that is to use the PAT interfaces, which > doesn't have this drawback -- then MTRR cleanup becomes entirely > superfluous and the problem goes away. Do you mean disable MTRR totally here? Regards zduan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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