kernel: Move default cache constants to caches

They are not related to the txdb, so a better place for them is the
new kernel and node cache file. Re-use the default amount of kernel
cache for the default node cache.

src/bitcoin-chainstate.cpp

@@ -19,9 +19,9 @@
 
 #include <consensus/validation.h>
 #include <core_io.h>
+#include <kernel/caches.h>
 #include <logging.h>
 #include <node/blockstorage.h>
-#include <node/caches.h>
 #include <node/chainstate.h>
 #include <random.h>
 #include <script/sigcache.h>
@@ -123,7 +123,7 @@ int main(int argc, char* argv[])
     util::SignalInterrupt interrupt;
     ChainstateManager chainman{interrupt, chainman_opts, blockman_opts};
 
-    kernel::CacheSizes cache_sizes{nDefaultDbCache << 20};
+    kernel::CacheSizes cache_sizes{DEFAULT_KERNEL_CACHE << 20};
     node::ChainstateLoadOptions options;
     auto [status, error] = node::LoadChainstate(chainman, cache_sizes, options);
     if (status != node::ChainstateLoadStatus::SUCCESS) {

src/init.cpp

@@ -487,7 +487,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
     argsman.AddArg("-conf=<file>", strprintf("Specify path to read-only configuration file. Relative paths will be prefixed by datadir location (only useable from command line, not configuration file) (default: %s)", BITCOIN_CONF_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-datadir=<dir>", "Specify data directory", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION, OptionsCategory::OPTIONS);
     argsman.AddArg("-dbbatchsize", strprintf("Maximum database write batch size in bytes (default: %u)", nDefaultDbBatchSize), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::OPTIONS);
-    argsman.AddArg("-dbcache=<n>", strprintf("Maximum database cache size <n> MiB (minimum %d, default: %d). Make sure you have enough RAM. In addition, unused memory allocated to the mempool is shared with this cache (see -maxmempool).", nMinDbCache, nDefaultDbCache), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    argsman.AddArg("-dbcache=<n>", strprintf("Maximum database cache size <n> MiB (minimum %d, default: %d). Make sure you have enough RAM. In addition, unused memory allocated to the mempool is shared with this cache (see -maxmempool).", MIN_DB_CACHE, DEFAULT_DB_CACHE), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-includeconf=<file>", "Specify additional configuration file, relative to the -datadir path (only useable from configuration file, not command line)", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-allowignoredconf", strprintf("For backwards compatibility, treat an unused %s file in the datadir as a warning, not an error.", BITCOIN_CONF_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-loadblock=<file>", "Imports blocks from external file on startup", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);

src/kernel/caches.h

@@ -9,6 +9,8 @@
 
 #include <algorithm>
 
+//! Suggested default amount of cache reserved for the kernel (MiB)
+static constexpr int64_t DEFAULT_KERNEL_CACHE{450};
 //! Max memory allocated to block tree DB specific cache (bytes)
 static constexpr size_t MAX_BLOCK_DB_CACHE{2_MiB};
 //! Max memory allocated to coin DB specific cache (bytes)

src/node/caches.cpp

@@ -7,7 +7,6 @@
 #include <common/args.h>
 #include <index/txindex.h>
 #include <kernel/caches.h>
-#include <txdb.h>
 
 #include <algorithm>
 #include <string>
@@ -22,8 +21,8 @@ static constexpr int64_t MAX_FILTER_INDEX_CACHE{1024};
 namespace node {
 CacheSizes CalculateCacheSizes(const ArgsManager& args, size_t n_indexes)
 {
-    int64_t nTotalCache = (args.GetIntArg("-dbcache", nDefaultDbCache) << 20);
-    nTotalCache = std::max(nTotalCache, nMinDbCache << 20); // total cache cannot be less than nMinDbCache
+    int64_t nTotalCache = (args.GetIntArg("-dbcache", DEFAULT_DB_CACHE) << 20);
+    nTotalCache = std::max(nTotalCache, MIN_DB_CACHE << 20);
     IndexCacheSizes sizes;
     sizes.tx_index = std::min(nTotalCache / 8, args.GetBoolArg("-txindex", DEFAULT_TXINDEX) ? MAX_TX_INDEX_CACHE << 20 : 0);
     nTotalCache -= sizes.tx_index;

src/node/caches.h

@@ -12,6 +12,11 @@
 
 class ArgsManager;
 
+//! min. -dbcache (MiB)
+static constexpr int64_t MIN_DB_CACHE{4};
+//! -dbcache default (MiB)
+static constexpr int64_t DEFAULT_DB_CACHE{DEFAULT_KERNEL_CACHE};
+
 namespace node {
 struct IndexCacheSizes {
     int64_t tx_index{0};

src/qt/optionsdialog.cpp

@@ -15,9 +15,9 @@
 
 #include <common/system.h>
 #include <interfaces/node.h>
-#include <node/chainstatemanager_args.h>
 #include <netbase.h>
-#include <txdb.h>
+#include <node/caches.h>
+#include <node/chainstatemanager_args.h>
 #include <util/strencodings.h>
 
 #include <chrono>
@@ -95,7 +95,7 @@ OptionsDialog::OptionsDialog(QWidget* parent, bool enableWallet)
     ui->verticalLayout->setStretchFactor(ui->tabWidget, 1);
 
     /* Main elements init */
-    ui->databaseCache->setRange(nMinDbCache, std::numeric_limits<int>::max());
+    ui->databaseCache->setRange(MIN_DB_CACHE, std::numeric_limits<int>::max());
     ui->threadsScriptVerif->setMinimum(-GetNumCores());
     ui->threadsScriptVerif->setMaximum(MAX_SCRIPTCHECK_THREADS);
     ui->pruneWarning->setVisible(false);

src/qt/optionsmodel.cpp

@@ -15,8 +15,8 @@
 #include <mapport.h>
 #include <net.h>
 #include <netbase.h>
+#include <node/caches.h>
 #include <node/chainstatemanager_args.h>
-#include <txdb.h> // for -dbcache defaults
 #include <util/string.h>
 #include <validation.h>    // For DEFAULT_SCRIPTCHECK_THREADS
 #include <wallet/wallet.h> // For DEFAULT_SPEND_ZEROCONF_CHANGE
@@ -470,7 +470,7 @@ QVariant OptionsModel::getOption(OptionID option, const std::string& suffix) con
                suffix.empty()          ? getOption(option, "-prev") :
                                          DEFAULT_PRUNE_TARGET_GB;
     case DatabaseCache:
-        return qlonglong(SettingToInt(setting(), nDefaultDbCache));
+        return qlonglong(SettingToInt(setting(), DEFAULT_DB_CACHE));
     case ThreadsScriptVerif:
         return qlonglong(SettingToInt(setting(), DEFAULT_SCRIPTCHECK_THREADS));
     case Listen:
@@ -733,7 +733,7 @@ void OptionsModel::checkAndMigrate()
         // see https://github.com/bitcoin/bitcoin/pull/8273
         // force people to upgrade to the new value if they are using 100MB
         if (settingsVersion < 130000 && settings.contains("nDatabaseCache") && settings.value("nDatabaseCache").toLongLong() == 100)
-            settings.setValue("nDatabaseCache", (qint64)nDefaultDbCache);
+            settings.setValue("nDatabaseCache", (qint64)DEFAULT_DB_CACHE);
 
         settings.setValue(strSettingsVersionKey, CLIENT_VERSION);
     }

src/txdb.h

@@ -21,12 +21,8 @@
 class COutPoint;
 class uint256;
 
-//! -dbcache default (MiB)
-static const int64_t nDefaultDbCache = 450;
 //! -dbbatchsize default (bytes)
 static const int64_t nDefaultDbBatchSize = 16 << 20;
-//! min. -dbcache (MiB)
-static const int64_t nMinDbCache = 4;
 
 //! User-controlled performance and debug options.
 struct CoinsViewOptions {