From: Yinghai Lu Date: Sat, 4 Oct 2008 21:50:32 +0000 (-0700) Subject: x86: mtrr_cleanup: first 1M may be covered in var mtrrs X-Git-Url: http://git.maemo.org/git/?a=commitdiff_plain;h=99e1aa17ce434010dd820b583628370cc15f10f3;p=h-e-n 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: Yinghai Lu Signed-off-by: H. Peter Anvin --- diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c index 9086b38..663e530 100644 --- a/arch/x86/kernel/cpu/mtrr/main.c +++ b/arch/x86/kernel/cpu/mtrr/main.c @@ -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));