x86: Use online node real index in calulate_tbl_offset()

Found a NUMA system that doesn't have RAM installed at the first
socket which hangs while executing init scripts.

bisected it to:

 | commit 932967202182743c01a2eee4bdfa2c42697bc586
 | Author: Shaohua Li <shaohua.li@intel.com>
 | Date:   Wed Oct 20 11:07:03 2010 +0800
 |
 |     x86: Spread tlb flush vector between nodes

It turns out when first socket is not online it could have cpus on
node1 tlb_offset set to bigger than NUM_INVALIDATE_TLB_VECTORS.

That could affect systems like 4 sockets, but socket 2 doesn't
have installed, sockets 3 will get too big tlb_offset.

Need to use real online node idx.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Shaohua Li <shaohua.li@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4CDEDE59.40603@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/tlb.c

@@ -223,7 +223,7 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
 
 static void __cpuinit calculate_tlb_offset(void)
 {
-	int cpu, node, nr_node_vecs;
+	int cpu, node, nr_node_vecs, idx = 0;
 	/*
 	 * we are changing tlb_vector_offset for each CPU in runtime, but this
 	 * will not cause inconsistency, as the write is atomic under X86. we
@@ -239,7 +239,7 @@ static void __cpuinit calculate_tlb_offset(void)
 		nr_node_vecs = NUM_INVALIDATE_TLB_VECTORS/nr_online_nodes;
 
 	for_each_online_node(node) {
-		int node_offset = (node % NUM_INVALIDATE_TLB_VECTORS) *
+		int node_offset = (idx % NUM_INVALIDATE_TLB_VECTORS) *
 			nr_node_vecs;
 		int cpu_offset = 0;
 		for_each_cpu(cpu, cpumask_of_node(node)) {
@@ -248,6 +248,7 @@ static void __cpuinit calculate_tlb_offset(void)
 			cpu_offset++;
 			cpu_offset = cpu_offset % nr_node_vecs;
 		}
+		idx++;
 	}
 }