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Commit 99e1aa17 authored by Yinghai Lu's avatar Yinghai Lu Committed by H. Peter Anvin
Browse files

x86: mtrr_cleanup: first 1M may be covered in var mtrrs 



The first 1M is don't care when it comes to the variables MTRRs.
Cover it as WB as a heuristic approximation; this is generally what we
want to minimize the number of registers.

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 42fde7a0

arch/x86/kernel/cpu/mtrr/main.c

+9 −0
Original line number Diff line number Diff line
@@ -1293,6 +1293,15 @@ static int __init mtrr_cleanup(unsigned address_bits) 
	}

	nr_range = x86_get_mtrr_mem_range(range, 0, extra_remove_base,

					  extra_remove_size);

	/*

	 * [0, 1M) should always be coverred by var mtrr with WB

	 * and fixed mtrrs should take effective before var mtrr for it

	 */

	nr_range = add_range_with_merge(range, nr_range, 0,

					(1ULL<<(20 - PAGE_SHIFT)) - 1);

	/* sort the ranges */

	sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);



	range_sums = sum_ranges(range, nr_range);

	printk(KERN_INFO "total RAM coverred: %ldM\n",

	       range_sums >> (20 - PAGE_SHIFT));