2007-09-11 Josh Stone <joshua.i.stone@intel.com>

	* systemtap.maps/pmap_agg_overflow.stp: Ensure that the percpu arrays
	don't overflow before we get the chance to test aggregation overflow.
	Also use a more optimal overflow limit (MAXMAPENTRIES + 1).

1 files changed, 10 insertions, 4 deletions

diff --git a/testsuite/systemtap.maps/pmap_agg_overflow.stp b/testsuite/systemtap.maps/pmap_agg_overflow.stp
index aa54c6a9..314cf13b 100755
--- a/testsuite/systemtap.maps/pmap_agg_overflow.stp
+++ b/testsuite/systemtap.maps/pmap_agg_overflow.stp
@@ -1,20 +1,26 @@
 # try to induce overflow of pmap aggregation
 #   (this will only work on smp machines)
 
-global stat, count, max_count
+global stat, count, pcpu_count, max_count
 
 probe begin {
     if (num_online_cpus() < 2) {
         warn("This test only applies to smp systems...")
         exit()
     }
-    max_count = num_online_cpus() * max_map_entries()
+    max_count = max_map_entries() + 1
 }
 
 probe kernel.function("scheduler_tick") {
+    # Be sure not to overflow the percpu array
+    if (++pcpu_count[cpu()] > max_map_entries())
+        next
+
     i = ++count
-    if (i >= max_count) exit()
-    stat[i] <<< i
+    if (i <= max_count)
+        stat[i] <<< i
+    else
+        exit()
 }
 
 probe end {