Shmem: Send acks also for local regions

fairmq/shmem/Manager.cxx

@@ -183,7 +183,6 @@ Region* Manager::GetRegionUnsafe(const uint64_t id)
             // LOG(debug) << "Located remote region with id '" << id << "', path: '" << path << "', flags: '" << flags << "'";
 
             auto r = fRegions.emplace(id, tools::make_unique<Region>(*this, id, 0, true, nullptr, path, flags));
-            r.first->second->StartSendingAcks();
             return r.first->second.get();
         } catch (bie& e) {
             LOG(warn) << "Could not get remote region for id: " << id;

fairmq/shmem/Region.cxx

@@ -19,6 +19,7 @@
 
 #include <cerrno>
 #include <chrono>
+#include <ios>
 
 using namespace std;
 
@@ -49,7 +50,17 @@ Region::Region(Manager& manager, uint64_t id, uint64_t size, bool remote, Region
     if (path != "") {
         fName = string(path + fName);
 
-        fFile = fopen(fName.c_str(), fRemote ? "r+" : "w+");
+        if (!fRemote) {
+            // create a file
+            filebuf fbuf;
+            if (fbuf.open(fName, ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary)) {
+                // set the size
+                fbuf.pubseekoff(size - 1, ios_base::beg);
+                fbuf.sputc(0);
+            }
+        }
+
+        fFile = fopen(fName.c_str(), "r+");
 
         if (!fFile) {
             LOG(error) << "Failed to initialize file: " << fName;
@@ -70,6 +81,7 @@ Region::Region(Manager& manager, uint64_t id, uint64_t size, bool remote, Region
     }
 
     InitializeQueues();
+    StartSendingAcks();
     LOG(debug) << "shmem: initialized region: " << fName;
 }