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authorYinghai Lu <yinghai@kernel.org>2012-06-06 10:55:40 -0700
committerIngo Molnar <mingo@kernel.org>2012-06-08 11:40:50 +0200
commitbd2753b2dda7bb43c7468826de75f49c6a7e8965 (patch)
tree1c3c02c226132e257aa77b2db5ae56ed78f4e02b
parent743628e868c5992354fc80b4d1e9a6143da1c0e6 (diff)
x86/mm: Only add extra pages count for the first memory range during pre-allocation early page table space
Robin found this regression: | I just tried to boot an 8TB system. It fails very early in boot with: | Kernel panic - not syncing: Cannot find space for the kernel page tables git bisect commit 722bc6b16771ed80871e1fd81c86d3627dda2ac8. A git revert of that commit does boot past that point on the 8TB configuration. That commit will add up extra pages for all memory range even above 4g. Try to limit that extra page count adding to first entry only. Bisected-by: Robin Holt <holt@sgi.com> Tested-by: Robin Holt <holt@sgi.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/CAE9FiQUj3wyzQxtq9yzBNc9u220p8JZ1FYHG7t%3DMOzJ%3D9BZMYA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/mm/init.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 97141c26a13a..bc4e9d84157f 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -62,7 +62,8 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en
extra += PMD_SIZE;
#endif
/* The first 2/4M doesn't use large pages. */
- extra += mr->end - mr->start;
+ if (mr->start < PMD_SIZE)
+ extra += mr->end - mr->start;
ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
} else