[SPARC]: Migration cost tune up in sparc smp.

This patch sets the max_cache_size value required to tune up
scheduler in SMP systems. Otherwise, the calculated
migration_cost is too high and task scheduling may lock up.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/sparc/kernel/smp.c b/arch/sparc/kernel/smp.c
index a93f5da6855d..40b42c88e6a7 100644
--- a/arch/sparc/kernel/smp.c
+++ b/arch/sparc/kernel/smp.c
@@ -69,6 +69,17 @@ void __init smp_store_cpu_info(int id)
                                                      "clock-frequency", 0);
         cpu_data(id).prom_node = cpu_node;
         cpu_data(id).mid = cpu_get_hwmid(cpu_node);
+
+        /* this is required to tune the scheduler correctly */
+        /* is it possible to have CPUs with different cache sizes? */
+        if (id == boot_cpu_id) {
+                int cache_line,cache_nlines;
+                cache_line = 0x20;
+                cache_line = prom_getintdefault(cpu_node, "ecache-line-size", cache_line);
+                cache_nlines = 0x8000;
+                cache_nlines = prom_getintdefault(cpu_node, "ecache-nlines", cache_nlines);
+                max_cache_size = cache_line * cache_nlines;
+        }
         if (cpu_data(id).mid < 0)
                 panic("No MID found for CPU%d at node 0x%08d", id, cpu_node);
 }