From 99ab39ca8f7dd659d6d8bc12bbff5a054991246b Mon Sep 17 00:00:00 2001
From: Alexey Rybalchenko <alexryba@gmail.com>
Date: Wed, 8 Dec 2021 23:21:55 +0100
Subject: [PATCH] shm: always open_or_create segment

---
 fairmq/shmem/Manager.h | 29 ++++++++++-------------------
 1 file changed, 10 insertions(+), 19 deletions(-)

diff --git a/fairmq/shmem/Manager.h b/fairmq/shmem/Manager.h
index a921201d..5b4f98cd 100644
--- a/fairmq/shmem/Manager.h
+++ b/fairmq/shmem/Manager.h
@@ -195,11 +195,8 @@ class Manager
         fHeartbeatThread = std::thread(&Manager::Heartbeats, this);
 
         try {
-            std::stringstream ss;
             boost::interprocess::scoped_lock<boost::interprocess::interprocess_mutex> lock(*fShmMtx);
 
-            fShmSegments = fManagementSegment.find_or_construct<Uint16SegmentInfoHashMap>(unique_instance)(fShmVoidAlloc);
-
             SessionInfo* sessionInfo = fManagementSegment.find<SessionInfo>(unique_instance).first;
             if (sessionInfo) {
                 LOG(debug) << "session info found, name: " << sessionInfo->fSessionName << ", creator id: " << sessionInfo->fCreatorId;
@@ -218,8 +215,6 @@ class Manager
                 LOG(debug) << "initialized event counter with: " << fEventCounter->fCount;
             }
 
-            fShmRegions = fManagementSegment.find_or_construct<Uint16RegionInfoHashMap>(unique_instance)(fShmVoidAlloc);
-
             fDeviceCounter = fManagementSegment.find<DeviceCounter>(unique_instance).first;
             if (fDeviceCounter) {
                 LOG(debug) << "device counter found, with value of " << fDeviceCounter->fCount << ". incrementing.";
@@ -231,22 +226,21 @@ class Manager
                 LOG(debug) << "initialized device counter with: " << fDeviceCounter->fCount;
             }
 
-            std::string op("create/open");
+            fShmSegments = fManagementSegment.find_or_construct<Uint16SegmentInfoHashMap>(unique_instance)(fShmVoidAlloc);
+            fShmRegions = fManagementSegment.find_or_construct<Uint16RegionInfoHashMap>(unique_instance)(fShmVoidAlloc);
 
             try {
                 std::string segmentName("fmq_" + fShmId + "_m_" + std::to_string(fSegmentId));
                 auto it = fShmSegments->find(fSegmentId);
                 if (it == fShmSegments->end()) {
-                    op = "create";
                     // no segment with given id exists, creating
                     if (allocationAlgorithm == "rbtree_best_fit") {
-                        fSegments.emplace(fSegmentId, RBTreeBestFitSegment(create_only, segmentName.c_str(), size));
+                        fSegments.emplace(fSegmentId, RBTreeBestFitSegment(open_or_create, segmentName.c_str(), size));
                         fShmSegments->emplace(fSegmentId, AllocationAlgorithm::rbtree_best_fit);
                     } else if (allocationAlgorithm == "simple_seq_fit") {
-                        fSegments.emplace(fSegmentId, SimpleSeqFitSegment(create_only, segmentName.c_str(), size));
+                        fSegments.emplace(fSegmentId, SimpleSeqFitSegment(open_or_create, segmentName.c_str(), size));
                         fShmSegments->emplace(fSegmentId, AllocationAlgorithm::simple_seq_fit);
                     }
-                    ss << "Created ";
                     (fEventCounter->fCount)++;
                     if (mlockSegmentOnCreation) {
                         MlockSegment(fSegmentId);
@@ -255,31 +249,28 @@ class Manager
                         ZeroSegment(fSegmentId);
                     }
                 } else {
-                    op = "open";
                     // found segment with the given id, opening
                     if (it->second.fAllocationAlgorithm == AllocationAlgorithm::rbtree_best_fit) {
-                        fSegments.emplace(fSegmentId, RBTreeBestFitSegment(open_only, segmentName.c_str()));
+                        fSegments.emplace(fSegmentId, RBTreeBestFitSegment(open_or_create, segmentName.c_str(), size));
                         if (allocationAlgorithm != "rbtree_best_fit") {
                             LOG(warn) << "Allocation algorithm of the opened segment is rbtree_best_fit, but requested is " << allocationAlgorithm << ". Ignoring requested setting.";
                             allocationAlgorithm = "rbtree_best_fit";
                         }
                     } else {
-                        fSegments.emplace(fSegmentId, SimpleSeqFitSegment(open_only, segmentName.c_str()));
+                        fSegments.emplace(fSegmentId, SimpleSeqFitSegment(open_or_create, segmentName.c_str(), size));
                         if (allocationAlgorithm != "simple_seq_fit") {
                             LOG(warn) << "Allocation algorithm of the opened segment is simple_seq_fit, but requested is " << allocationAlgorithm << ". Ignoring requested setting.";
                             allocationAlgorithm = "simple_seq_fit";
                         }
                     }
-                    ss << "Opened ";
                 }
-                ss << "shared memory segment '" << "fmq_" << fShmId << "_m_" << fSegmentId << "'."
+                LOG(debug) << "Created/opened shared memory segment '" << "fmq_" << fShmId << "_m_" << fSegmentId << "'."
                 << " Size: " << boost::apply_visitor(SegmentSize(), fSegments.at(fSegmentId)) << " bytes."
                 << " Available: " << boost::apply_visitor(SegmentFreeMemory(), fSegments.at(fSegmentId)) << " bytes."
                 << " Allocation algorithm: " << allocationAlgorithm;
-                LOG(debug) << ss.str();
             } catch (interprocess_exception& bie) {
-                LOG(error) << "Failed to " << op << " shared memory segment (" << "fmq_" << fShmId << "_m_" << fSegmentId << "): " << bie.what();
-                throw TransportError(tools::ToString("Failed to ", op, " shared memory segment (", "fmq_", fShmId, "_m_", fSegmentId, "): ", bie.what()));
+                LOG(error) << "Failed to create/open shared memory segment '" << "fmq_" << fShmId << "_m_" << fSegmentId << "': " << bie.what();
+                throw TransportError(tools::ToString("Failed to create/open shared memory segment '", "fmq_", fShmId, "_m_", fSegmentId, "': ", bie.what()));
             }
 
             if (mlockSegment) {
@@ -817,7 +808,7 @@ class Manager
     uint64_t fShmId64;
     std::string fShmId;
     uint16_t fSegmentId;
-    std::unordered_map<uint16_t, boost::variant<RBTreeBestFitSegment, SimpleSeqFitSegment>> fSegments;
+    std::unordered_map<uint16_t, boost::variant<RBTreeBestFitSegment, SimpleSeqFitSegment>> fSegments; // TODO: can use Segment class directly here
     boost::interprocess::managed_shared_memory fManagementSegment;
     VoidAlloc fShmVoidAlloc;
     boost::interprocess::interprocess_mutex* fShmMtx;