x86, numa: fix boot without RAM on node0 again

|commit e534c7c5f8d6e9fc46f57fab067c7e48d8ceb172
|Author: Lee Schermerhorn <[email protected]>
|Date:   Wed May 26 14:44:58 2010 -0700
|
|    numa: x86_64: use generic percpu var numa_node_id() implementation
|
|    x86 arch specific changes to use generic numa_node_id() based on generic
|    percpu variable infrastructure.  Back out x86's custom version of
|    numa_node_id()

broke numa system that doesn't have ram on node0 when MEMORY_HOTPLUG is enabled.

because cpu_up() will call cpu_to_node() before per_cpu(numa_node) is setup for APs.

When Node0 doesn't have RAM, on x86, cpus already round it to nearest node with RAM in x86_cpu_to_node_map. and per_cpu(numa_node) is not set up until in c_init for APs.

when later cpu_up() calling cpu_to_node() will get 0 again, and make it online even there is no RAM on node0. so later all APs can not booted up, and later will have panic.

[    1.611101] On node 0 totalpages: 0
.........
[    2.608558] On node 0 totalpages: 0
[    2.612065] Brought up 1 CPUs
[    2.615199] Total of 1 processors activated (3990.31 BogoMIPS).
...
   93.225341] calling  loop_init+0x0/0x1a4 @ 1
[   93.229314] PERCPU: allocation failed, size=80 align=8, failed to populate
[   93.246539] Pid: 1, comm: swapper Tainted: G        W   2.6.35-rc4-tip-yh-04371-gd64e6c4-dirty #354
[   93.264621] Call Trace:
[   93.266533]  [<ffffffff81125e43>] pcpu_alloc+0x83a/0x8e7
[   93.270710]  [<ffffffff81125f15>] __alloc_percpu+0x10/0x12
[   93.285849]  [<ffffffff8140786c>] alloc_disk_node+0x94/0x16d
[   93.291811]  [<ffffffff81407956>] alloc_disk+0x11/0x13
[   93.306157]  [<ffffffff81503e51>] loop_alloc+0xa7/0x180
[   93.310538]  [<ffffffff8277ef48>] loop_init+0x9b/0x1a4
[   93.324909]  [<ffffffff8277eead>] ? loop_init+0x0/0x1a4
[   93.329650]  [<ffffffff810001f2>] do_one_initcall+0x57/0x136
[   93.345197]  [<ffffffff827486d0>] kernel_init+0x184/0x20e
[   93.348146]  [<ffffffff81034954>] kernel_thread_helper+0x4/0x10
[   93.365194]  [<ffffffff81c7cc3c>] ? restore_args+0x0/0x30
[   93.369305]  [<ffffffff8274854c>] ? kernel_init+0x0/0x20e
[   93.386011]  [<ffffffff81034950>] ? kernel_thread_helper+0x0/0x10
[   93.392047] loop: out of memory

...

Try to assign per_cpu(numa_node) early

---
 arch/x86/kernel/setup_percpu.c |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Index: linux-2.6/arch/x86/kernel/setup_percpu.c
===================================================================
@@ -238,6 +238,15 @@ void __init setup_per_cpu_areas(void)
 #ifdef CONFIG_NUMA
 		per_cpu(x86_cpu_to_node_map, cpu) =
 			early_per_cpu_map(x86_cpu_to_node_map, cpu);
+		/*
+		 * make sure boot cpu numa_node is right, when boot cpu is on
+		 *  the node that doesn't have mem installed
+		 * also cpu_up() will call cpu_to_node() for APs when
+		 *  MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
+		 *  up later with c_init aka intel_init/amd_init
+		 * So set them all (boot cpu and all APs)
+		 */
+		set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
 #endif
 #endif
 		/*

@@ -257,14 +266,6 @@ void __init setup_per_cpu_areas(void)
 	early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 #endif
 
-#if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
-	/*
-	 * make sure boot cpu numa_node is right, when boot cpu is on the
-	 * node that doesn't have mem installed
-	 */
-	set_cpu_numa_node(boot_cpu_id, early_cpu_to_node(boot_cpu_id));
-#endif
-
 	/* Setup node to cpumask map */
 	setup_node_to_cpumask_map();