osc/rdma: fix bug in dynamic memory window tracking code

This commit fixes an ordering bug in the code that keeps track of all
attached memory windows. The code is intended to keep the memory
regions sorted but was often inserting at the wrong index. Thanks to
Christoph Niethammer for reporting the issue. The reproducer will be
added to nightly MTT testing.

Fixes open-mpi/ompi#2012

Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>

ompi/mca/osc/rdma/osc_rdma_dynamic.c

@@ -1,6 +1,6 @@
 /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
 /*
- * Copyright (c) 2014-2015 Los Alamos National Security, LLC.  All rights
+ * Copyright (c) 2014-2016 Los Alamos National Security, LLC.  All rights
  *                         reserved.
  * $COPYRIGHT$
  *
@@ -14,6 +14,7 @@
 
 #include "mpi.h"
 
+#include "opal/util/sys_limits.h"
 
 /**
  * ompi_osc_rdma_find_region_containing:
@@ -71,9 +72,11 @@ static ompi_osc_rdma_region_t *find_insertion_point (ompi_osc_rdma_region_t *reg
     int mid_index = (max_index + min_index) >> 1;
     ompi_osc_rdma_region_t *region = (ompi_osc_rdma_region_t *)((intptr_t) regions + mid_index * region_size);
 
+    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "find_insertion_point (%d, %d, %lx, %lu)\n", min_index, max_index, base, region_size);
+
     if (max_index < min_index) {
-        *region_index = mid_index;
-        return region;
+        *region_index = min_index;
+        return (ompi_osc_rdma_region_t *)((intptr_t) regions + min_index * region_size);
     }
 
     if (region->base > base) {
@@ -92,7 +95,7 @@ int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
     osc_rdma_counter_t region_count;
     osc_rdma_counter_t region_id;
     void *bound;
-    intptr_t page_size = getpagesize ();
+    intptr_t page_size = opal_getpagesize ();
     int region_index;
     int ret;