Run expiration on a separate thread

scripts/base/init-bare.zeek

@@ -6222,8 +6222,9 @@ module Storage;
 
 export {
 	## The interval used by the storage framework for automatic expiration
-	## of elements in all backends that don't support it natively.
-	const expire_interval = 5.0 secs &redef;
+	## of elements in all backends that don't support it natively, or if
+	## using expiration while reading pcap files.
+	const expire_interval = 15.0 secs &redef;
 }
 
 module GLOBAL;

src/3rdparty

@@ -1 +1 @@
-Subproject commit 0d15c8be14851914c8fd2d378bb700dae7e7b991
+Subproject commit 059a4a369f2a52d8013f0645b69e1bf2194e97c6

src/storage/Manager.cc

@@ -2,17 +2,31 @@
 
 #include "zeek/storage/Manager.h"
 
+#include <atomic>
+
 #include "zeek/Desc.h"
+#include "zeek/RunState.h"
 
 #include "const.bif.netvar_h"
 
+std::atomic_flag expire_running;
+
 namespace zeek::storage {
 
 void detail::ExpirationTimer::Dispatch(double t, bool is_expire) {
     if ( is_expire )
         return;
 
-    storage_mgr->Expire();
+    // If there isn't an active thread, spin up a new one. Expiration may take
+    // some time to complete and we want it to get all the way done before we
+    // start another one running. If this causes us to skip a cycle, that's not
+    // a big deal as the next cycle will catch anything that should be expired
+    // in the interim.
+    if ( ! expire_running.test_and_set() ) {
+        DBG_LOG(DBG_STORAGE, "Starting new expiration thread");
+        storage_mgr->expiration_thread = std::jthread([]() { storage_mgr->Expire(); });
+    }
+
     storage_mgr->StartExpirationTimer();
 }
 
@@ -62,7 +76,9 @@ ErrorResult Manager::OpenBackend(BackendPtr backend, RecordValPtr options, TypeP
 }
 
 ErrorResult Manager::CloseBackend(BackendPtr backend, ErrorResultCallback* cb) {
-    // Remove from the list always, even if the close may fail below and even in an async context.
+    // Expiration runs on a separate thread and loops over the vector of backends. The mutex
+    // here ensures exclusive access. This one happens in a block because we can remove the
+    // backend from the vector before actually closing it.
     {
         std::unique_lock<std::mutex> lk(backends_mtx);
         auto it = std::find(backends.begin(), backends.end(), backend);
@@ -80,22 +96,34 @@ ErrorResult Manager::CloseBackend(BackendPtr backend, ErrorResultCallback* cb) {
 }
 
 void Manager::Expire() {
-    DBG_LOG(DBG_STORAGE, "Expire running, have %zu backends to check", backends.size());
+    // Expiration runs on a separate thread and loops over the vector of backends. The mutex
+    // here ensures exclusive access.
     std::unique_lock<std::mutex> lk(backends_mtx);
-    for ( const auto& b : backends ) {
-        if ( b->IsOpen() )
-            b->Expire();
+
+    DBG_LOG(DBG_STORAGE, "Expiration running, have %zu backends to check", backends.size());
+
+    for ( auto it = backends.begin(); it != backends.end() && ! run_state::terminating; ++it ) {
+        if ( (*it)->IsOpen() )
+            (*it)->Expire();
     }
+
+    expire_running.clear();
 }
 
 void Manager::StartExpirationTimer() {
     zeek::detail::timer_mgr->Add(
         new detail::ExpirationTimer(run_state::network_time + zeek::BifConst::Storage::expire_interval));
+    DBG_LOG(DBG_STORAGE, "Next expiration check at %f",
+            run_state::network_time + zeek::BifConst::Storage::expire_interval);
 }
 
 void Manager::RegisterBackend(BackendPtr backend) {
+    // Expiration runs on a separate thread and loops over the vector of backends. The mutex
+    // here ensures exclusive access.
     std::unique_lock<std::mutex> lk(backends_mtx);
+
     backends.push_back(std::move(backend));
+    DBG_LOG(DBG_STORAGE, "Registered backends: %zu", backends.size());
 }
 
 } // namespace zeek::storage

src/storage/Manager.h

@@ -3,7 +3,9 @@
 #pragma once
 
 #include <mutex>
+#include <thread>
 
+#include "zeek/3rdparty/jthread.hpp"
 #include "zeek/Timer.h"
 #include "zeek/plugin/ComponentManager.h"
 #include "zeek/storage/Backend.h"
@@ -65,10 +67,13 @@ public:
      */
     ErrorResult CloseBackend(BackendPtr backend, ErrorResultCallback* cb = nullptr);
 
+    void Expire();
+
 protected:
     friend class storage::detail::ExpirationTimer;
-    void Expire();
+    void RunExpireThread();
     void StartExpirationTimer();
+    std::jthread expiration_thread;
 
     friend class storage::OpenResultCallback;
     void RegisterBackend(BackendPtr backend);