[PATCH 11/12]: sparc64: Only allocate per-cpu areas for possiblecpus.

From: David Miller
Date: Thu Apr 09 2009 - 01:42:23 EST



This gets us real close to the generic implementation of
setup_per_cpu_areas() except:

1) We store the per-cpu offset into the trap_block[], whereas
the generic code has it's own static array.

2) We have to initialize the %g5 register to hold the boot cpu's
per-cpu area offset.

3) The OBP/MDESC cpu info scan is performed at the end.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
arch/sparc/kernel/smp_64.c | 22 ++++++----------------
1 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index af0b28e..168025f 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1373,27 +1373,17 @@ void smp_send_stop(void)

void __init setup_per_cpu_areas(void)
{
- unsigned long base, shift, goal, size, i;
+ unsigned long size, i, nr_possible_cpus = num_possible_cpus();
char *ptr;

/* Copy section for each CPU (we discard the original) */
- goal = PERCPU_ENOUGH_ROOM;
+ size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
+ ptr = alloc_bootmem_pages(size * nr_possible_cpus);

- shift = PAGE_SHIFT;
- for (size = PAGE_SIZE; size < goal; size <<= 1UL)
- shift++;
-
- ptr = __alloc_bootmem(size * NR_CPUS, PAGE_SIZE, 0);
- if (!ptr) {
- prom_printf("Cannot allocate per-cpu memory.\n");
- prom_halt();
- }
-
- base = ptr - __per_cpu_start;
-
- for (i = 0; i < NR_CPUS; i++, ptr += size) {
- __per_cpu_offset(i) = base + (i * size);
+ for_each_possible_cpu(i) {
+ __per_cpu_offset(i) = ptr - __per_cpu_start;
memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
+ ptr += size;
}

/* Setup %g5 for the boot cpu. */
--
1.6.2.2

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