No need to restart sampling or reconfigure anything unless the config has changed.

5 files changed, 34 insertions, 13 deletions

diff --git a/searchcore/src/tests/proton/server/disk_mem_usage_filter/disk_mem_usage_filter_test.cpp b/searchcore/src/tests/proton/server/disk_mem_usage_filter/disk_mem_usage_filter_test.cpp
index dd38765c4f0..ccee7caa917 100644
--- a/searchcore/src/tests/proton/server/disk_mem_usage_filter/disk_mem_usage_filter_test.cpp
+++ b/searchcore/src/tests/proton/server/disk_mem_usage_filter/disk_mem_usage_filter_test.cpp
@@ -65,9 +65,17 @@ assertResourceUsage(double usage, double limit, double utilization, const Resour
     EXPECT_DOUBLE_EQ(utilization, state.utilization());
 }
 
+TEST_F(DiskMemUsageFilterTest, reconfig_with_identical_config_is_noop)
+{
+    EXPECT_TRUE(_filter.setConfig(Config(1.0, 0.8)));
+    assertResourceUsage(0.2, 0.8, 0.25, _filter.usageState().diskState());
+    EXPECT_FALSE(_filter.setConfig(Config(1.0, 0.8)));
+    assertResourceUsage(0.2, 0.8, 0.25, _filter.usageState().diskState());
+}
+
 TEST_F(DiskMemUsageFilterTest, disk_limit_can_be_reached)
 {
-    _filter.setConfig(Config(1.0, 0.8));
+    EXPECT_TRUE(_filter.setConfig(Config(1.0, 0.8)));
     assertResourceUsage(0.2, 0.8, 0.25, _filter.usageState().diskState());
     triggerDiskLimit();
     testWrite("diskLimitReached: { "
@@ -80,7 +88,7 @@ TEST_F(DiskMemUsageFilterTest, disk_limit_can_be_reached)
 
 TEST_F(DiskMemUsageFilterTest, memory_limit_can_be_reached)
 {
-    _filter.setConfig(Config(0.8, 1.0));
+    EXPECT_TRUE(_filter.setConfig(Config(0.8, 1.0)));
     assertResourceUsage(0.3, 0.8, 0.375, _filter.usageState().memoryState());
     triggerMemoryLimit();
     testWrite("memoryLimitReached: { "
@@ -95,7 +103,7 @@ TEST_F(DiskMemUsageFilterTest, memory_limit_can_be_reached)
 
 TEST_F(DiskMemUsageFilterTest, both_disk_limit_and_memory_limit_can_be_reached)
 {
-    _filter.setConfig(Config(0.8, 0.8));
+    EXPECT_TRUE(_filter.setConfig(Config(0.8, 0.8)));
     triggerMemoryLimit();
     triggerDiskLimit();
     testWrite("memoryLimitReached: { "
diff --git a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.cpp b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.cpp
index 54eea6565cb..fc1d23741c2 100644
--- a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.cpp
@@ -188,12 +188,14 @@ DiskMemUsageFilter::set_resource_usage(const TransientResourceUsage& transient_u
     recalcState(guard);
 }
 
-void
+bool
 DiskMemUsageFilter::setConfig(Config config_in)
 {
     Guard guard(_lock);
+    if (_config == config_in) return false;
     _config = config_in;
     recalcState(guard);
+    return true;
 }
 
 vespalib::ProcessMemoryStats
diff --git a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.h b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.h
index 16e4d1d6869..cc901fa72cf 100644
--- a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.h
+++ b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_filter.h
@@ -24,7 +24,6 @@ namespace proton {
 class DiskMemUsageFilter : public IResourceWriteFilter,
                            public IDiskMemUsageNotifier {
 public:
-    using space_info = std::filesystem::space_info;
     using Mutex = std::mutex;
     using Guard = std::lock_guard<Mutex>;
 
@@ -39,6 +38,12 @@ public:
             : _memoryLimit(memoryLimit_in),
               _diskLimit(diskLimit_in)
         { }
+        bool operator == (const Config & rhs) const noexcept {
+            return (_memoryLimit == rhs._memoryLimit) && (_diskLimit == rhs._diskLimit);
+        }
+        bool operator != (const Config & rhs) const noexcept {
+            return ! (*this == rhs);
+        }
     };
 
 private:
@@ -66,7 +71,7 @@ public:
     DiskMemUsageFilter(const HwInfo &hwInfo);
     ~DiskMemUsageFilter() override;
     void set_resource_usage(const TransientResourceUsage& transient_usage, vespalib::ProcessMemoryStats memoryStats, uint64_t diskUsedSizeBytes);
-    void setConfig(Config config);
+    [[nodiscard]] bool setConfig(Config config);
     vespalib::ProcessMemoryStats getMemoryStats() const;
     uint64_t getDiskUsedSize() const;
     TransientResourceUsage get_transient_resource_usage() const;
diff --git a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.cpp b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.cpp
index 102d947e812..3e35e42d25a 100644
--- a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.cpp
@@ -29,21 +29,25 @@ DiskMemUsageSampler::close() {
     _periodicHandle.reset();
 }
 
+bool
+DiskMemUsageSampler::timeToSampleAgain() const noexcept {
+    return vespalib::steady_clock::now() >= (_lastSampleTime + _sampleInterval);
+}
+
 void
 DiskMemUsageSampler::setConfig(const Config &config, IScheduledExecutor & executor)
 {
-    _periodicHandle.reset();
-    _filter.setConfig(config.filterConfig);
+    bool wasChanged = _filter.setConfig(config.filterConfig);
+    if (_periodicHandle && (_sampleInterval == config.sampleInterval) && !wasChanged)
+        return;
     _sampleInterval = config.sampleInterval;
+    _periodicHandle.reset();
     sampleAndReportUsage();
-    _lastSampleTime = vespalib::steady_clock::now();
     vespalib::duration maxInterval = std::min(vespalib::duration(1s), _sampleInterval);
     _periodicHandle = executor.scheduleAtFixedRate(makeLambdaTask([this]() {
-        if (_filter.acceptWriteOperation() && (vespalib::steady_clock::now() < (_lastSampleTime + _sampleInterval))) {
-            return;
+        if (!_filter.acceptWriteOperation() || timeToSampleAgain()) {
+            sampleAndReportUsage();
         }
-        sampleAndReportUsage();
-        _lastSampleTime = vespalib::steady_clock::now();
     }), maxInterval, maxInterval);
 }
 
@@ -60,6 +64,7 @@ DiskMemUsageSampler::sampleAndReportUsage()
     vespalib::ProcessMemoryStats memoryStats = sampleMemoryUsage();
     uint64_t diskUsage = sampleDiskUsage();
     _filter.set_resource_usage(transientUsage, memoryStats, diskUsage);
+    _lastSampleTime = vespalib::steady_clock::now();
 }
 
 namespace {
diff --git a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.h b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.h
index 16c89a253fd..d434c529836 100644
--- a/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.h
+++ b/searchcore/src/vespa/searchcore/proton/server/disk_mem_usage_sampler.h
@@ -27,6 +27,7 @@ class DiskMemUsageSampler {
     uint64_t sampleDiskUsage();
     vespalib::ProcessMemoryStats sampleMemoryUsage();
     TransientResourceUsage sample_transient_resource_usage();
+    [[nodiscard]] bool timeToSampleAgain() const noexcept;
 public:
     struct Config {
         DiskMemUsageFilter::Config filterConfig;