Increase ARGO_VM_START to resolve PMIx conflict (#152)

* Increase ARGO_VM_START to resolve PMIx conflict

Increase the ARGO_VM_START address in order to avoid a shared
memory conflict with PMIx in newer OpenMPI versions (#151).
As a result, ARGO_VM_SIZE is reduced to ensure that the end of
the ArgoDSM virtual memory reservation remains unchanged.

* Fix cpplint issue

Author: lundgren87

src/data_distribution/first_touch_distribution.hpp

@@ -272,7 +272,7 @@ void first_touch_distribution<instance>::first_touch(const std::size_t& addr) {
 		/* iterate through the nodes to find a valid offset for the page, starting from the currently running one */
 		bool succeeded = false;
 		std::size_t n, searched;
-		for(n = rank, searched = 0; searched < static_cast<std::size_t>(base_distribution<instance>::nodes);
+		for (n = rank, searched = 0; searched < static_cast<std::size_t>(base_distribution<instance>::nodes);
 				n = (n + 1) % base_distribution<instance>::nodes, searched++) {
 			/* load backing offset for the node from the offsets table */
 			argo::backend::atomic::_load_local_offsets_tbl(&offset, rank, n);
@@ -281,7 +281,11 @@ void first_touch_distribution<instance>::first_touch(const std::size_t& addr) {
 				/* try to claim a valid offset */
 				const std::size_t incr_offset = offset + granularity;
 				argo::backend::atomic::_compare_exchange_offsets_tbl(&incr_offset, &offset, &result, sizeof(std::size_t), n, n);
-				if (result == offset) { succeeded = true; homenode = n; break; }
+				if (result == offset) {
+					succeeded = true;
+					homenode = n;
+					break;
+				}
 				offset = result;
 			}
 			/* cache the offset returned from a remote CAS operation */

src/virtual_memory/vm_limits.hpp

@@ -11,20 +11,20 @@
  * @brief The start of the ArgoDSM virtual memory space
  * @note This value assumes x86_64 architecture
  *
- * The ArgoDSM virtual memory space leaves the first 1/6 for local use.
+ * The ArgoDSM virtual memory space leaves the lower part for local use.
  */
-char* const ARGO_VM_START = reinterpret_cast<char*>(0x155555554000l);
+char* const ARGO_VM_START = reinterpret_cast<char*>(0x355555554000l);
 
 /**
  * @brief The maximum size of the ArgoDSM virtual memory space
  * @note This value assumes x86_64 architecture
  *
- * ArgoDSM reserves up to half of the available user-space virtual memory. A
- * particular VM implementation may choose to reserve less than this number.
+ * ArgoDSM reserves up to a quarter of the available user-space virtual memory.
+ * A particular VM implementation may choose to reserve less than this number.
  * In combination with @ref ARGO_VM_START this ensures that the final third
  * of the virtual memory is left for PIE loads, heap, shared libraries and
  * the stack among other things.
  */
-constexpr ptrdiff_t ARGO_VM_SIZE = 0x400000000000l;
+constexpr ptrdiff_t ARGO_VM_SIZE = 0x200000000000l;
 
 #endif  // ARGODSM_SRC_VIRTUAL_MEMORY_VM_LIMITS_HPP_