x86: introduce max_low_pfn_mapped for 64-bit
when more than 4g memory is installed, don't map the big hole below 4g.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index b5a0fd5..029e8cf 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -50,6 +50,7 @@
unsigned int __VMALLOC_RESERVE = 128 << 20;
+unsigned long max_low_pfn_mapped;
unsigned long max_pfn_mapped;
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);