Russ Anderson
2008-02-05T19:32:33Z

[patch] Fix large MCA bootmem allocation

The MCA code allocates bootmem memory for NR_CPUS, regardless
of how many cpus the system actually has. This change allocates
memory only for cpus that actually exist.

On my test system with NR_CPUS = 1024, reserved memory was reduced by 130944k.

Before: Memory: 27886976k/28111168k available (8282k code, 242304k reserved, 5928k data, 1792k init)
After: Memory: 28017920k/28111168k available (8282k code, 111360k reserved, 5928k data, 1792k init)

Signed-off-by: Russ Anderson <rja@sgi.com>

---
arch/ia64/kernel/mca.c | 52 +++++++++++++++++++++----------------------------
1 file changed, 23 insertions(+), 29 deletions(-)

Index: test/arch/ia64/kernel/mca.c
=================================--- test.orig/arch/ia64/kernel/mca.c 2008-02-05 13:01:56.000000000 -0600
+++ test/arch/ia64/kernel/mca.c 2008-02-05 13:12:34.921332805 -0600
@@ -17,7 +17,7 @@
* Copyright (C) 2000 Intel
* Copyright (C) Chuck Fleckenstein <cfleck@co.intel.com>
*
- * Copyright (C) 1999, 2004 Silicon Graphics, Inc.
+ * Copyright (C) 1999, 2004-2008 Silicon Graphics, Inc.
* Copyright (C) Vijay Chander <vijay@engr.sgi.com>
*
* Copyright (C) 2006 FUJITSU LIMITED
@@ -1762,11 +1762,8 @@ format_mca_init_stack(void *mca_data, un
/* Caller prevents this from being called after init */
static void * __init_refok mca_bootmem(void)
{
- void *p;
-
- p = alloc_bootmem(sizeof(struct ia64_mca_cpu) * NR_CPUS +
- KERNEL_STACK_SIZE);
- return (void *)ALIGN((unsigned long)p, KERNEL_STACK_SIZE);
+ return __alloc_bootmem(sizeof(struct ia64_mca_cpu),
+ KERNEL_STACK_SIZE, 0);
}

/* Do per-CPU MCA-related initialization. */
@@ -1774,33 +1771,30 @@ void __cpuinit
ia64_mca_cpu_init(void *cpu_data)
{
void *pal_vaddr;
+ void *data;
+ long sz = sizeof(struct ia64_mca_cpu);
+ int cpu = smp_processor_id();
static int first_time = 1;

- if (first_time) {
- void *mca_data;
- int cpu;
-
- first_time = 0;
- mca_data = mca_bootmem();
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- format_mca_init_stack(mca_data,
- offsetof(struct ia64_mca_cpu, mca_stack),
- "MCA", cpu);
- format_mca_init_stack(mca_data,
- offsetof(struct ia64_mca_cpu, init_stack),
- "INIT", cpu);
- __per_cpu_mca[cpu] = __pa(mca_data);
- mca_data += sizeof(struct ia64_mca_cpu);
- }
- }
-
/*
- * The MCA info structure was allocated earlier and its
- * physical address saved in __per_cpu_mca[cpu]. Copy that
- * address * to ia64_mca_data so we can access it as a per-CPU
- * variable.
+ * Structure will already be allocated if cpu has been online,
+ * then offlined.
*/
- __get_cpu_var(ia64_mca_data) = __per_cpu_mca[smp_processor_id()];
+ if (__per_cpu_mca[cpu]) {
+ data = __va(__per_cpu_mca[cpu]);
+ } else {
+ if (first_time) {
+ data = mca_bootmem();
+ first_time = 0;
+ } else
+ data = page_address(alloc_pages_node(numa_node_id(),
+ GFP_KERNEL, get_order(sz)));
+ }
+ format_mca_init_stack(data, offsetof(struct ia64_mca_cpu, mca_stack),
+ "MCA", cpu);
+ format_mca_init_stack(data, offsetof(struct ia64_mca_cpu, init_stack),
+ "INIT", cpu);
+ __get_cpu_var(ia64_mca_data) = __per_cpu_mca[cpu] = __pa(data);

/*
* Stash away a copy of the PTE needed to map the per-CPU page.
--
Russ Anderson, OS RAS/Partitioning Project Lead
SGI - Silicon Graphics Inc rja@sgi.com