[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: NKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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);
 }