cuckoocache: Return approximate memory size

Returning the approximate total size eliminates the need for
InitS*Cache() to do nElems*sizeof(uint256). The cuckoocache has a better
idea of this information.

src/bitcoin-chainstate.cpp

@@ -62,8 +62,8 @@ int main(int argc, char* argv[])
     // Necessary for CheckInputScripts (eventually called by ProcessNewBlock),
     // which will try the script cache first and fall back to actually
     // performing the check with the signature cache.
-    InitSignatureCache();
-    InitScriptExecutionCache();
+    Assert(InitSignatureCache());
+    Assert(InitScriptExecutionCache());
 
 
     // SETUP: Scheduling and Background Signals

src/cuckoocache.h

@@ -336,8 +336,8 @@ public:
     uint32_t setup(uint32_t new_size)
     {
         // depth_limit must be at least one otherwise errors can occur.
-        depth_limit = static_cast<uint8_t>(std::log2(static_cast<float>(std::max((uint32_t)2, new_size))));
         size = std::max<uint32_t>(2, new_size);
+        depth_limit = static_cast<uint8_t>(std::log2(static_cast<float>(size)));
         table.resize(size);
         collection_flags.setup(size);
         epoch_flags.resize(size);
@@ -357,12 +357,16 @@ public:
      *
      * @param bytes the approximate number of bytes to use for this data
      * structure
-     * @returns the maximum number of elements storable (see setup()
-     * documentation for more detail)
+     * @returns A pair of the maximum number of elements storable (see setup()
+     * documentation for more detail) and the approxmiate total size of these
+     * elements in bytes.
      */
-    uint32_t setup_bytes(size_t bytes)
+    std::pair<uint32_t, size_t> setup_bytes(size_t bytes)
     {
-        return setup(bytes/sizeof(Element));
+        auto num_elems = setup(bytes/sizeof(Element));
+
+        size_t approx_size_bytes = num_elems * sizeof(Element);
+        return std::make_pair(num_elems, approx_size_bytes);
     }
 
     /** insert loops at most depth_limit times trying to insert a hash

src/init.cpp

@@ -1115,8 +1115,9 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                   args.GetArg("-datadir", ""), fs::PathToString(fs::current_path()));
     }
 
-    InitSignatureCache();
-    InitScriptExecutionCache();
+    if (!InitSignatureCache() || !InitScriptExecutionCache()) {
+        return InitError(strprintf(_("Unable to allocate memory for -maxsigcachesize: '%s' MiB"), args.GetIntArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE)));
+    }
 
     int script_threads = args.GetIntArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
     if (script_threads <= 0) {

src/script/sigcache.cpp

@@ -75,7 +75,7 @@ public:
         std::unique_lock<std::shared_mutex> lock(cs_sigcache);
         setValid.insert(entry);
     }
-    uint32_t setup_bytes(size_t n)
+    std::pair<uint32_t, size_t> setup_bytes(size_t n)
     {
         return setValid.setup_bytes(n);
     }
@@ -92,14 +92,18 @@ static CSignatureCache signatureCache;
 
 // To be called once in AppInitMain/BasicTestingSetup to initialize the
 // signatureCache.
-void InitSignatureCache()
+bool InitSignatureCache()
 {
     // nMaxCacheSize is unsigned. If -maxsigcachesize is set to zero,
     // setup_bytes creates the minimum possible cache (2 elements).
     size_t nMaxCacheSize = std::min(std::max((int64_t)0, gArgs.GetIntArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) / 2), MAX_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
-    size_t nElems = signatureCache.setup_bytes(nMaxCacheSize);
+
+    auto setup_results = signatureCache.setup_bytes(nMaxCacheSize);
+
+    const auto [num_elems, approx_size_bytes] = setup_results;
     LogPrintf("Using %zu MiB out of %zu/2 requested for signature cache, able to store %zu elements\n",
-            (nElems*sizeof(uint256)) >>20, (nMaxCacheSize*2)>>20, nElems);
+              approx_size_bytes >> 20, (nMaxCacheSize * 2) >> 20, num_elems);
+    return true;
 }
 
 bool CachingTransactionSignatureChecker::VerifyECDSASignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const

src/script/sigcache.h

@@ -33,6 +33,6 @@ public:
     bool VerifySchnorrSignature(Span<const unsigned char> sig, const XOnlyPubKey& pubkey, const uint256& sighash) const override;
 };
 
-void InitSignatureCache();
+[[nodiscard]] bool InitSignatureCache();
 
 #endif // BITCOIN_SCRIPT_SIGCACHE_H

src/test/util/setup_common.cpp

@@ -133,8 +133,8 @@ BasicTestingSetup::BasicTestingSetup(const std::string& chainName, const std::ve
     m_node.kernel = std::make_unique<kernel::Context>();
     SetupEnvironment();
     SetupNetworking();
-    InitSignatureCache();
-    InitScriptExecutionCache();
+    Assert(InitSignatureCache());
+    Assert(InitScriptExecutionCache());
     m_node.chain = interfaces::MakeChain(m_node);
     fCheckBlockIndex = true;
     static bool noui_connected = false;

src/validation.cpp

@@ -1656,7 +1656,7 @@ bool CScriptCheck::operator()() {
 static CuckooCache::cache<uint256, SignatureCacheHasher> g_scriptExecutionCache;
 static CSHA256 g_scriptExecutionCacheHasher;
 
-void InitScriptExecutionCache() {
+bool InitScriptExecutionCache() {
     // Setup the salted hasher
     uint256 nonce = GetRandHash();
     // We want the nonce to be 64 bytes long to force the hasher to process
@@ -1667,9 +1667,13 @@ void InitScriptExecutionCache() {
     // nMaxCacheSize is unsigned. If -maxsigcachesize is set to zero,
     // setup_bytes creates the minimum possible cache (2 elements).
     size_t nMaxCacheSize = std::min(std::max((int64_t)0, gArgs.GetIntArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) / 2), MAX_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
-    size_t nElems = g_scriptExecutionCache.setup_bytes(nMaxCacheSize);
+
+    auto setup_results = g_scriptExecutionCache.setup_bytes(nMaxCacheSize);
+
+    const auto [num_elems, approx_size_bytes] = setup_results;
     LogPrintf("Using %zu MiB out of %zu/2 requested for script execution cache, able to store %zu elements\n",
-            (nElems*sizeof(uint256)) >>20, (nMaxCacheSize*2)>>20, nElems);
+              approx_size_bytes >> 20, (nMaxCacheSize * 2) >> 20, num_elems);
+    return true;
 }
 
 /**

src/validation.h

@@ -323,7 +323,7 @@ public:
 };
 
 /** Initializes the script-execution cache */
-void InitScriptExecutionCache();
+[[nodiscard]] bool InitScriptExecutionCache();
 
 /** Functions for validating blocks and updating the block tree */