Subtract transient resource usage from the absolute usage before reporting to the cluster controller.

This ensures that the transient resource usage is covered by the resource headroom on the content node,
instead of leading to feed blocked due to natural fluctuations.

2 files changed, 19 insertions, 4 deletions

diff --git a/searchcore/src/tests/proton/persistenceengine/resource_usage_tracker/resource_usage_tracker_test.cpp b/searchcore/src/tests/proton/persistenceengine/resource_usage_tracker/resource_usage_tracker_test.cpp
index 313f3e9a270..c0d94ba6376 100644
--- a/searchcore/src/tests/proton/persistenceengine/resource_usage_tracker/resource_usage_tracker_test.cpp
+++ b/searchcore/src/tests/proton/persistenceengine/resource_usage_tracker/resource_usage_tracker_test.cpp
@@ -57,9 +57,10 @@ public:
 
     ~ResourceUsageTrackerTest();
 
-    void notify(double disk_usage, double memory_usage)
+    void notify(double disk_usage, double memory_usage, double transient_disk_usage = 0.0, double transient_memory_usage = 0.0)
     {
-        _notifier.notify(DiskMemUsageState({ 0.8, disk_usage }, { 0.8, memory_usage }));
+        _notifier.notify(DiskMemUsageState({ 0.8, disk_usage }, { 0.8, memory_usage },
+                                           transient_disk_usage, transient_memory_usage));
     }
 
     ResourceUsage get_usage() { return _listener->get_usage(); }
@@ -77,6 +78,15 @@ TEST_F(ResourceUsageTrackerTest, resource_usage_is_forwarded_to_listener)
     EXPECT_EQ(ResourceUsage(0.75, 0.25), get_usage());
 }
 
+TEST_F(ResourceUsageTrackerTest, transient_resource_usage_is_subtracted_from_absolute_usage)
+{
+    auto register_guard = _tracker->set_listener(*_listener);
+    notify(0.8, 0.5, 0.4, 0.2);
+    EXPECT_EQ(ResourceUsage(0.4, 0.3), get_usage());
+    notify(0.8, 0.5, 0.9, 0.6);
+    EXPECT_EQ(ResourceUsage(0.0, 0.0), get_usage());
+}
+
 TEST_F(ResourceUsageTrackerTest, forwarding_depends_on_register_guard)
 {
     auto register_guard = _tracker->set_listener(*_listener);
diff --git a/searchcore/src/vespa/searchcore/proton/persistenceengine/resource_usage_tracker.cpp b/searchcore/src/vespa/searchcore/proton/persistenceengine/resource_usage_tracker.cpp
index 6307604598d..63e8b1d5196 100644
--- a/searchcore/src/vespa/searchcore/proton/persistenceengine/resource_usage_tracker.cpp
+++ b/searchcore/src/vespa/searchcore/proton/persistenceengine/resource_usage_tracker.cpp
@@ -94,8 +94,13 @@ void
 ResourceUsageTracker::notifyDiskMemUsage(DiskMemUsageState state)
 {
     std::lock_guard guard(_lock);
-    // TODO: Subtract transient resource (memory and disk) usage from the absolute numbers.
-    _resource_usage = ResourceUsage(state.diskState().usage(), state.memoryState().usage(), _resource_usage.get_attribute_address_space_usage());
+    // The transient resource usage is subtracted from the absolute resource usage
+    // before it eventually is reported to the cluster controller (to decide whether to block client feed).
+    // This ensures that the transient resource usage is covered by the resource headroom on the content node,
+    // instead of leading to feed blocked due to natural fluctuations.
+    double adj_disk_usage = std::max(0.0, state.diskState().usage() - state.transient_disk_usage());
+    double adj_memory_usage = std::max(0.0, state.memoryState().usage() - state.transient_memory_usage());
+    _resource_usage = ResourceUsage(adj_disk_usage, adj_memory_usage, _resource_usage.get_attribute_address_space_usage());
     if (_listener != nullptr) {
         _listener->update_resource_usage(_resource_usage);
     }