From fc2e1e4cad358de37758fb95a432c8778765f5f1 Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@yahoo-inc.com>
Date: Mon, 1 Feb 2021 16:57:01 +0000
Subject: Use conditional notify instead of sleep.

---
 .../filestorage/filestormanagertest.cpp            |  1 +
 .../persistence/filestorage/filestormanager.cpp    | 27 ++++++++++++----------
 .../persistence/filestorage/filestormanager.h      |  5 ++--
 3 files changed, 19 insertions(+), 14 deletions(-)

(limited to 'storage')

diff --git a/storage/src/tests/persistence/filestorage/filestormanagertest.cpp b/storage/src/tests/persistence/filestorage/filestormanagertest.cpp
index beecaddf5e4..5a7a4394da4 100644
--- a/storage/src/tests/persistence/filestorage/filestormanagertest.cpp
+++ b/storage/src/tests/persistence/filestorage/filestormanagertest.cpp
@@ -482,6 +482,7 @@ TEST_F(FileStorManagerTest, sync_waits_for_already_started_tasks) {
         executor->sync();
         syncComplete = true;
     });
+    std::this_thread::sleep_for(100us);
     EXPECT_FALSE(syncComplete);
     gate.countDown();
     thread.join();
diff --git a/storage/src/vespa/storage/persistence/filestorage/filestormanager.cpp b/storage/src/vespa/storage/persistence/filestorage/filestormanager.cpp
index 38def4f775e..42f9e876eee 100644
--- a/storage/src/vespa/storage/persistence/filestorage/filestormanager.cpp
+++ b/storage/src/vespa/storage/persistence/filestorage/filestormanager.cpp
@@ -82,6 +82,8 @@ FileStorManager(const config::ConfigUri & configUri, spi::PersistenceProvider& p
       _filestorHandler(),
       _sequencedExecutor(),
       _executeLock(),
+      _syncCond(),
+      _notifyAfterExecute(false),
       _executeCount(0),
       _tasksInExecute(),
       _closed(false),
@@ -1003,6 +1005,9 @@ void
 FileStorManager::TrackExecutedTasks::run() {
     std::lock_guard guard(_manager._executeLock);
     _manager._tasksInExecute.erase(_serialNum);
+    if (_manager._notifyAfterExecute) {
+        _manager._syncCond.notify_all();
+    }
 }
 
 std::unique_ptr<spi::BucketTask>
@@ -1016,28 +1021,26 @@ FileStorManager::execute(const spi::Bucket &bucket, std::unique_ptr<spi::BucketT
     return task;
 }
 
+namespace {
 bool
-FileStorManager::areTaskCompleteUntil(size_t limit) const
-{
-    std::lock_guard guard(_executeLock);
-    for (size_t serial : _tasksInExecute) {
+areTasksCompleteUntil(const vespalib::hash_set<size_t> &inFlight, size_t limit) {
+    for (size_t serial : inFlight) {
         if (serial < limit) {
             return false;
         }
     }
     return true;
 }
+}
 
 void
 FileStorManager::sync() {
-    size_t serialNumLimit;
-    {
-        std::lock_guard guard(_executeLock);
-        serialNumLimit = _executeCount;
-    }
-    while ( ! areTaskCompleteUntil(serialNumLimit)) {
-        std::this_thread::sleep_for(100us);
-    }
+    std::unique_lock guard(_executeLock);
+    _notifyAfterExecute = true;
+    _syncCond.wait(guard, [this, limit=_executeCount]() {
+        return areTasksCompleteUntil(_tasksInExecute, limit);
+    });
+    _notifyAfterExecute = false;
 }
 
 } // storage
diff --git a/storage/src/vespa/storage/persistence/filestorage/filestormanager.h b/storage/src/vespa/storage/persistence/filestorage/filestormanager.h
index da47ed64f4a..fea1b9c7ea6 100644
--- a/storage/src/vespa/storage/persistence/filestorage/filestormanager.h
+++ b/storage/src/vespa/storage/persistence/filestorage/filestormanager.h
@@ -72,7 +72,9 @@ class FileStorManager : public StorageLinkQueued,
     std::shared_ptr<FileStorMetrics> _metrics;
     std::unique_ptr<FileStorHandler> _filestorHandler;
     std::unique_ptr<vespalib::ISequencedTaskExecutor> _sequencedExecutor;
-    mutable std::mutex         _executeLock;
+    std::mutex                 _executeLock;
+    std::condition_variable    _syncCond;
+    bool                       _notifyAfterExecute;
     size_t                     _executeCount;
     vespalib::hash_set<size_t> _tasksInExecute;
 
@@ -82,7 +84,6 @@ class FileStorManager : public StorageLinkQueued,
     std::unique_ptr<vespalib::IDestructorCallback> _bucketExecutorRegistration;
     ServiceLayerHostInfoReporter                   _host_info_reporter;
     std::unique_ptr<vespalib::IDestructorCallback> _resource_usage_listener_registration;
-    bool areTaskCompleteUntil(size_t serialNum) const;
     class TrackExecutedTasks;
 public:
     FileStorManager(const config::ConfigUri &, spi::PersistenceProvider&,
-- 
cgit v1.2.3