From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751040Ab3FIUAq (ORCPT ); Sun, 9 Jun 2013 16:00:46 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:34622 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822Ab3FIUAo (ORCPT ); Sun, 9 Jun 2013 16:00:44 -0400 From: Yinghai Lu To: "H. Peter Anvin" , Andrew Morton Cc: Thomas Gleixner , Ingo Molnar , Joshua Covington , linux-kernel@vger.kernel.org, Yinghai Lu , Subject: [PATCH 1/2] x86,mtrr: Fix original mtrr range get for mtrr_cleanup Date: Sun, 9 Jun 2013 13:00:04 -0700 Message-Id: <1370808005-23565-1-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.1.4 X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joshua reported: Commit cd7b304dfaf1 (x86, range: fix missing merge during add range) broke mtrr cleanup on his setup in 3.9.5. corresponding commit in upstream is fbe06b7bae7c. *BAD*gran_size: 64K chunk_size: 16M num_reg: 6 lose cover RAM: -0G https://bugzilla.kernel.org/show_bug.cgi?id=59491 So it rejects new var mtrr layout. It turns out we have some problem with initial mtrr range retrievel. current sequence is: x86_get_mtrr_mem_range ==> bunchs of add_range_with_merge ==> bunchs of subract_range ==> clean_sort_range add_range_with_merge for [0,1M) sort_range() add_range_with_merge could have blank slots, so we can not just sort only, that will have final result have extra blank slot in head. So move that calling add_range_with_merge for [0,1M), with that we could avoid extra clean_sort_range calling. Reported-by: Joshua Covington Signed-off-by: Yinghai Lu Cc: v3.9 --- arch/x86/kernel/cpu/mtrr/cleanup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) Index: linux-2.6/arch/x86/kernel/cpu/mtrr/cleanup.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/cleanup.c +++ linux-2.6/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -714,15 +714,15 @@ int __init mtrr_cleanup(unsigned address if (mtrr_tom2) x_remove_size = (mtrr_tom2 >> PAGE_SHIFT) - x_remove_base; - nr_range = x86_get_mtrr_mem_range(range, 0, x_remove_base, x_remove_size); /* * [0, 1M) should always be covered by var mtrr with WB * and fixed mtrrs should take effect before var mtrr for it: */ nr_range = add_range_with_merge(range, RANGE_NUM, nr_range, 0, 1ULL<<(20 - PAGE_SHIFT)); - /* Sort the ranges: */ - sort_range(range, nr_range); + /* add from var mtrr at last */ + nr_range = x86_get_mtrr_mem_range(range, nr_range, + x_remove_base, x_remove_size); range_sums = sum_ranges(range, nr_range); printk(KERN_INFO "total RAM covered: %ldM\n",