Add GC Cancel/Stop (#568)

- GcScheduler will now cancel any running GC when it shuts down.
  - Old GC is rather limited in *when* it reacts to cancel of GC. GCv2 is more responsive.

1 files changed, 60 insertions, 11 deletions

diff --git a/src/zenserver/cache/cachedisklayer.cpp b/src/zenserver/cache/cachedisklayer.cpp
index af8b6227b..6ab3c7746 100644
--- a/src/zenserver/cache/cachedisklayer.cpp
+++ b/src/zenserver/cache/cachedisklayer.cpp
@@ -54,6 +54,13 @@ namespace {
 
 #pragma pack(pop)
 
+	template<typename T>
+	void Reset(T& V)
+	{
+		T Tmp;
+		V.swap(Tmp);
+	}
+
 	const char* IndexExtension = ".uidx";
 	const char* LogExtension   = ".slog";
 
@@ -2367,6 +2374,7 @@ public:
 	{
 		Stopwatch  Timer;
 		const auto _ = MakeGuard([&] {
+			Reset(m_ExpiredStandaloneKeys);
 			if (!Ctx.Settings.Verbose)
 			{
 				return;
@@ -2384,6 +2392,10 @@ public:
 			ExtendablePathBuilder<256> Path;
 			for (const std::pair<IoHash, uint64_t>& ExpiredKey : m_ExpiredStandaloneKeys)
 			{
+				if (Ctx.IsCancelledFlag.load())
+				{
+					return;
+				}
 				Path.Reset();
 				m_Bucket.BuildPath(Path, ExpiredKey.first);
 				fs::path FilePath = Path.ToPath();
@@ -2543,6 +2555,11 @@ public:
 								}
 								m_Bucket.m_SlogFile.Append(MovedEntries);
 								Stats.RemovedDisk += FreedDiskSpace;
+								if (Ctx.IsCancelledFlag.load())
+								{
+									return false;
+								}
+								return true;
 							},
 							ClaimDiskReserveCallback);
 					}
@@ -2558,7 +2575,6 @@ public:
 				}
 			}
 		}
-		m_ExpiredStandaloneKeys.clear();
 	}
 
 private:
@@ -2593,6 +2609,11 @@ ZenCacheDiskLayer::CacheBucket::RemoveExpiredData(GcCtx& Ctx, GcStats& Stats)
 	uint64_t								 RemovedStandaloneSize = 0;
 	{
 		RwLock::ExclusiveLockScope IndexLock(m_IndexLock);
+		if (Ctx.IsCancelledFlag.load())
+		{
+			return nullptr;
+		}
+
 		TotalEntries = m_Index.size();
 
 		// Find out expired keys
@@ -2625,6 +2646,11 @@ ZenCacheDiskLayer::CacheBucket::RemoveExpiredData(GcCtx& Ctx, GcStats& Stats)
 		Stats.CheckedCount += TotalEntries;
 		Stats.FoundCount += ExpiredEntries.size();
 
+		if (Ctx.IsCancelledFlag.load())
+		{
+			return nullptr;
+		}
+
 		if (Ctx.Settings.IsDeleteMode)
 		{
 			for (const DiskIndexEntry& Entry : ExpiredEntries)
@@ -2656,6 +2682,11 @@ ZenCacheDiskLayer::CacheBucket::RemoveExpiredData(GcCtx& Ctx, GcStats& Stats)
 		}
 	}
 
+	if (Ctx.IsCancelledFlag.load())
+	{
+		return nullptr;
+	}
+
 	return new DiskBucketStoreCompactor(*this, std::move(ExpiredStandaloneKeys));
 }
 
@@ -2689,10 +2720,23 @@ public:
 		});
 
 		m_IndexLock = std::make_unique<RwLock::SharedLockScope>(m_CacheBucket.m_IndexLock);
+		if (Ctx.IsCancelledFlag.load())
+		{
+			m_UncachedReferences.clear();
+			m_IndexLock.reset();
+			return;
+		}
 
 		// Rescan to see if any cache items needs refreshing since last pass when we had the lock
 		for (const auto& Entry : m_CacheBucket.m_Index)
 		{
+			if (Ctx.IsCancelledFlag.load())
+			{
+				m_UncachedReferences.clear();
+				m_IndexLock.reset();
+				return;
+			}
+
 			size_t												 PayloadIndex = Entry.second;
 			const ZenCacheDiskLayer::CacheBucket::BucketPayload& Payload	  = m_CacheBucket.m_Payloads[PayloadIndex];
 			const DiskLocation&									 Loc		  = Payload.Location;
@@ -2782,6 +2826,11 @@ ZenCacheDiskLayer::CacheBucket::CreateReferenceCheckers(GcCtx& Ctx)
 		RwLock::SharedLockScope IndexLock(m_IndexLock);
 		for (const auto& Entry : m_Index)
 		{
+			if (Ctx.IsCancelledFlag.load())
+			{
+				return {};
+			}
+
 			size_t												 PayloadIndex = Entry.second;
 			const ZenCacheDiskLayer::CacheBucket::BucketPayload& Payload	  = m_Payloads[PayloadIndex];
 			const DiskLocation&									 Loc		  = Payload.Location;
@@ -2821,6 +2870,11 @@ ZenCacheDiskLayer::CacheBucket::CreateReferenceCheckers(GcCtx& Ctx)
 	{
 		for (const IoHash& Key : StandaloneKeys)
 		{
+			if (Ctx.IsCancelledFlag.load())
+			{
+				return {};
+			}
+
 			IoBuffer Buffer = GetStandaloneCacheValue(ZenContentType::kCbObject, Key);
 			if (!Buffer)
 			{
@@ -3047,12 +3101,9 @@ void
 ZenCacheDiskLayer::CacheBucket::ClearReferenceCache()
 {
 	RwLock::ExclusiveLockScope IndexLock(m_IndexLock);
-	m_FirstReferenceIndex.clear();
-	m_FirstReferenceIndex.shrink_to_fit();
-	m_ReferenceHashes.clear();
-	m_ReferenceHashes.shrink_to_fit();
-	m_NextReferenceHashesIndexes.clear();
-	m_NextReferenceHashesIndexes.shrink_to_fit();
+	Reset(m_FirstReferenceIndex);
+	Reset(m_ReferenceHashes);
+	Reset(m_NextReferenceHashesIndexes);
 	m_ReferenceCount = 0;
 }
 
@@ -3099,11 +3150,9 @@ ZenCacheDiskLayer::CacheBucket::CompactState(std::vector<BucketPayload>&  Payloa
 	m_Payloads.swap(Payloads);
 	m_AccessTimes.swap(AccessTimes);
 	m_MetaDatas.swap(MetaDatas);
-	m_FreeMetaDatas.clear();
-	m_FreeMetaDatas.shrink_to_fit();
+	Reset(m_FreeMetaDatas);
 	m_MemCachedPayloads.swap(MemCachedPayloads);
-	m_FreeMemCachedPayloads.clear();
-	m_FreeMetaDatas.shrink_to_fit();
+	Reset(m_FreeMemCachedPayloads);
 	if (m_Configuration.EnableReferenceCaching)
 	{
 		m_FirstReferenceIndex.swap(FirstReferenceIndex);