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 <joshuacov@googlemail.com>
Tested-by: Joshua Covington <joshuacov@googlemail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@vger.kernel.org> v3.9
---
arch/x86/kernel/cpu/mtrr/cleanup.c | 8 ++++----
1 file changed, 4 insertions(+), 4 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,
+ nr_range = add_range_with_merge(range, RANGE_NUM, 0, 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",
--
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