diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index ae2e2ae5e..aa69013b3 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -1,576 +1,576 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2018 The Bitcoin Core developers
 // Copyright (c) 2018-2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <rpc/server.h>
 
 #include <config.h>
 #include <rpc/util.h>
 #include <shutdown.h>
 #include <sync.h>
 #include <util/strencodings.h>
 
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 #include <boost/signals2/signal.hpp>
 
 #include <cassert>
 #include <memory> // for unique_ptr
 #include <mutex>
 #include <set>
 #include <unordered_map>
 
 static RecursiveMutex cs_rpcWarmup;
 static std::atomic<bool> g_rpc_running{false};
-static std::once_flag g_rpc_interrupt_flag;
-static std::once_flag g_rpc_stop_flag;
 static bool fRPCInWarmup GUARDED_BY(cs_rpcWarmup) = true;
 static std::string
     rpcWarmupStatus GUARDED_BY(cs_rpcWarmup) = "RPC server started";
 /* Timer-creating functions */
 static RPCTimerInterface *timerInterface = nullptr;
 /* Map of name to timer. */
 static Mutex g_deadline_timers_mutex;
 static std::map<std::string, std::unique_ptr<RPCTimerBase>>
     deadlineTimers GUARDED_BY(g_deadline_timers_mutex);
 static bool ExecuteCommand(Config &config, const CRPCCommand &command,
                            const JSONRPCRequest &request, UniValue &result,
                            bool last_handler);
 
 struct RPCCommandExecutionInfo {
     std::string method;
     int64_t start;
 };
 
 struct RPCServerInfo {
     Mutex mutex;
     std::list<RPCCommandExecutionInfo> active_commands GUARDED_BY(mutex);
 };
 
 static RPCServerInfo g_rpc_server_info;
 
 struct RPCCommandExecution {
     std::list<RPCCommandExecutionInfo>::iterator it;
     explicit RPCCommandExecution(const std::string &method) {
         LOCK(g_rpc_server_info.mutex);
         it = g_rpc_server_info.active_commands.insert(
             g_rpc_server_info.active_commands.cend(),
             {method, GetTimeMicros()});
     }
     ~RPCCommandExecution() {
         LOCK(g_rpc_server_info.mutex);
         g_rpc_server_info.active_commands.erase(it);
     }
 };
 
 UniValue RPCServer::ExecuteCommand(Config &config,
                                    const JSONRPCRequest &request) const {
     // Return immediately if in warmup
     // This is retained from the old RPC implementation because a lot of state
     // is set during warmup that RPC commands may depend on.  This can be
     // safely removed once global variable usage has been eliminated.
     {
         LOCK(cs_rpcWarmup);
         if (fRPCInWarmup) {
             throw JSONRPCError(RPC_IN_WARMUP, rpcWarmupStatus);
         }
     }
 
     std::string commandName = request.strMethod;
     {
         auto commandsReadView = commands.getReadView();
         auto iter = commandsReadView->find(commandName);
         if (iter != commandsReadView.end()) {
             return iter->second.get()->Execute(request);
         }
     }
 
     // TODO Remove the below call to tableRPC.execute() and only call it for
     // context-free RPC commands via an implementation of RPCCommand.
 
     // Check if context-free RPC method is valid and execute it
     return tableRPC.execute(config, request);
 }
 
 void RPCServer::RegisterCommand(std::unique_ptr<RPCCommand> command) {
     if (command != nullptr) {
         const std::string &commandName = command->GetName();
         commands.getWriteView()->insert(
             std::make_pair(commandName, std::move(command)));
     }
 }
 
 static struct CRPCSignals {
     boost::signals2::signal<void()> Started;
     boost::signals2::signal<void()> Stopped;
 } g_rpcSignals;
 
 void RPCServerSignals::OnStarted(std::function<void()> slot) {
     g_rpcSignals.Started.connect(slot);
 }
 
 void RPCServerSignals::OnStopped(std::function<void()> slot) {
     g_rpcSignals.Stopped.connect(slot);
 }
 
 std::string CRPCTable::help(Config &config, const std::string &strCommand,
                             const JSONRPCRequest &helpreq) const {
     std::string strRet;
     std::string category;
     std::set<intptr_t> setDone;
     std::vector<std::pair<std::string, const CRPCCommand *>> vCommands;
 
     for (const auto &entry : mapCommands) {
         vCommands.push_back(
             std::make_pair(entry.second.front()->category + entry.first,
                            entry.second.front()));
     }
     sort(vCommands.begin(), vCommands.end());
 
     JSONRPCRequest jreq(helpreq);
     jreq.fHelp = true;
     jreq.params = UniValue();
 
     for (const std::pair<std::string, const CRPCCommand *> &command :
          vCommands) {
         const CRPCCommand *pcmd = command.second;
         std::string strMethod = pcmd->name;
         if ((strCommand != "" || pcmd->category == "hidden") &&
             strMethod != strCommand) {
             continue;
         }
 
         jreq.strMethod = strMethod;
         try {
             UniValue unused_result;
             if (setDone.insert(pcmd->unique_id).second) {
                 pcmd->actor(config, jreq, unused_result,
                             true /* last_handler */);
             }
         } catch (const std::exception &e) {
             // Help text is returned in an exception
             std::string strHelp = std::string(e.what());
             if (strCommand == "") {
                 if (strHelp.find('\n') != std::string::npos) {
                     strHelp = strHelp.substr(0, strHelp.find('\n'));
                 }
 
                 if (category != pcmd->category) {
                     if (!category.empty()) {
                         strRet += "\n";
                     }
                     category = pcmd->category;
                     strRet += "== " + Capitalize(category) + " ==\n";
                 }
             }
             strRet += strHelp + "\n";
         }
     }
     if (strRet == "") {
         strRet = strprintf("help: unknown command: %s\n", strCommand);
     }
 
     strRet = strRet.substr(0, strRet.size() - 1);
     return strRet;
 }
 
 static UniValue help(Config &config, const JSONRPCRequest &jsonRequest) {
     if (jsonRequest.fHelp || jsonRequest.params.size() > 1) {
         throw std::runtime_error(RPCHelpMan{
             "help",
             "List all commands, or get help for a specified command.\n",
             {
                 {"command", RPCArg::Type::STR, /* default */ "all commands",
                  "The command to get help on"},
             },
             RPCResult{RPCResult::Type::STR, "", "The help text"},
             RPCExamples{""},
         }
                                      .ToString());
     }
 
     std::string strCommand;
     if (jsonRequest.params.size() > 0) {
         strCommand = jsonRequest.params[0].get_str();
     }
 
     return tableRPC.help(config, strCommand, jsonRequest);
 }
 
 static UniValue stop(const Config &config, const JSONRPCRequest &jsonRequest) {
     static const std::string RESULT{PACKAGE_NAME " stopping"};
     // Accept the deprecated and ignored 'detach' boolean argument
     // Also accept the hidden 'wait' integer argument (milliseconds)
     // For instance, 'stop 1000' makes the call wait 1 second before returning
     // to the client (intended for testing)
     if (jsonRequest.fHelp || jsonRequest.params.size() > 1) {
         throw std::runtime_error(RPCHelpMan{
             "stop",
             "\nRequest a graceful shutdown of " PACKAGE_NAME ".",
             {},
             RPCResult{RPCResult::Type::STR, "",
                       "A string with the content '" + RESULT + "'"},
             RPCExamples{""},
         }
                                      .ToString());
     }
 
     // Event loop will exit after current HTTP requests have been handled, so
     // this reply will get back to the client.
     StartShutdown();
     if (jsonRequest.params[0].isNum()) {
         UninterruptibleSleep(
             std::chrono::milliseconds{jsonRequest.params[0].get_int()});
     }
     return RESULT;
 }
 
 static UniValue uptime(const Config &config, const JSONRPCRequest &request) {
     RPCHelpMan{
         "uptime",
         "Returns the total uptime of the server.\n",
         {},
         RPCResult{RPCResult::Type::NUM, "",
                   "The number of seconds that the server has been running"},
         RPCExamples{HelpExampleCli("uptime", "") +
                     HelpExampleRpc("uptime", "")},
     }
         .Check(request);
 
     return GetTime() - GetStartupTime();
 }
 
 static UniValue getrpcinfo(const Config &config,
                            const JSONRPCRequest &request) {
     RPCHelpMan{
         "getrpcinfo",
         "Returns details of the RPC server.\n",
         {},
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::ARR,
                        "active_commands",
                        "All active commands",
                        {
                            {RPCResult::Type::OBJ,
                             "",
                             "Information about an active command",
                             {
                                 {RPCResult::Type::STR, "method",
                                  "The name of the RPC command"},
                                 {RPCResult::Type::NUM, "duration",
                                  "The running time in microseconds"},
                             }},
                        }},
                       {RPCResult::Type::STR, "logpath",
                        "The complete file path to the debug log"},
                   }},
         RPCExamples{HelpExampleCli("getrpcinfo", "") +
                     HelpExampleRpc("getrpcinfo", "")},
     }
         .Check(request);
 
     LOCK(g_rpc_server_info.mutex);
     UniValue active_commands(UniValue::VARR);
     for (const RPCCommandExecutionInfo &info :
          g_rpc_server_info.active_commands) {
         UniValue entry(UniValue::VOBJ);
         entry.pushKV("method", info.method);
         entry.pushKV("duration", GetTimeMicros() - info.start);
         active_commands.push_back(entry);
     }
 
     UniValue result(UniValue::VOBJ);
     result.pushKV("active_commands", active_commands);
 
     const std::string path = LogInstance().m_file_path.string();
     UniValue log_path(UniValue::VSTR, path);
     result.pushKV("logpath", log_path);
 
     return result;
 }
 
 // clang-format off
 static const CRPCCommand vRPCCommands[] = {
     //  category            name                      actor (function)        argNames
     //  ------------------- ------------------------  ----------------------  ----------
     /* Overall control/query calls */
     { "control",            "getrpcinfo",             getrpcinfo,             {}  },
     { "control",            "help",                   help,                   {"command"}  },
     { "control",            "stop",                   stop,                   {"wait"}  },
     { "control",            "uptime",                 uptime,                 {}  },
 };
 // clang-format on
 
 CRPCTable::CRPCTable() {
     unsigned int vcidx;
     for (vcidx = 0; vcidx < (sizeof(vRPCCommands) / sizeof(vRPCCommands[0]));
          vcidx++) {
         const CRPCCommand *pcmd;
 
         pcmd = &vRPCCommands[vcidx];
         mapCommands[pcmd->name].push_back(pcmd);
     }
 }
 
 bool CRPCTable::appendCommand(const std::string &name,
                               const CRPCCommand *pcmd) {
     if (IsRPCRunning()) {
         return false;
     }
 
     mapCommands[name].push_back(pcmd);
     return true;
 }
 
 bool CRPCTable::removeCommand(const std::string &name,
                               const CRPCCommand *pcmd) {
     auto it = mapCommands.find(name);
     if (it != mapCommands.end()) {
         auto new_end = std::remove(it->second.begin(), it->second.end(), pcmd);
         if (it->second.end() != new_end) {
             it->second.erase(new_end, it->second.end());
             return true;
         }
     }
     return false;
 }
 
 void StartRPC() {
     LogPrint(BCLog::RPC, "Starting RPC\n");
     g_rpc_running = true;
     g_rpcSignals.Started();
 }
 
 void InterruptRPC() {
+    static std::once_flag g_rpc_interrupt_flag;
     // This function could be called twice if the GUI has been started with
     // -server=1.
     std::call_once(g_rpc_interrupt_flag, []() {
         LogPrint(BCLog::RPC, "Interrupting RPC\n");
         // Interrupt e.g. running longpolls
         g_rpc_running = false;
     });
 }
 
 void StopRPC() {
+    static std::once_flag g_rpc_stop_flag;
     // This function could be called twice if the GUI has been started with
     // -server=1.
     assert(!g_rpc_running);
     std::call_once(g_rpc_stop_flag, []() {
         LogPrint(BCLog::RPC, "Stopping RPC\n");
         WITH_LOCK(g_deadline_timers_mutex, deadlineTimers.clear());
         DeleteAuthCookie();
         g_rpcSignals.Stopped();
     });
 }
 
 bool IsRPCRunning() {
     return g_rpc_running;
 }
 
 void RpcInterruptionPoint() {
     if (!IsRPCRunning()) {
         throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Shutting down");
     }
 }
 
 void SetRPCWarmupStatus(const std::string &newStatus) {
     LOCK(cs_rpcWarmup);
     rpcWarmupStatus = newStatus;
 }
 
 void SetRPCWarmupFinished() {
     LOCK(cs_rpcWarmup);
     assert(fRPCInWarmup);
     fRPCInWarmup = false;
 }
 
 bool RPCIsInWarmup(std::string *outStatus) {
     LOCK(cs_rpcWarmup);
     if (outStatus) {
         *outStatus = rpcWarmupStatus;
     }
     return fRPCInWarmup;
 }
 
 bool IsDeprecatedRPCEnabled(const ArgsManager &args,
                             const std::string &method) {
     const std::vector<std::string> enabled_methods =
         args.GetArgs("-deprecatedrpc");
 
     return find(enabled_methods.begin(), enabled_methods.end(), method) !=
            enabled_methods.end();
 }
 
 static UniValue JSONRPCExecOne(Config &config, RPCServer &rpcServer,
                                JSONRPCRequest jreq, const UniValue &req) {
     UniValue rpc_result(UniValue::VOBJ);
 
     try {
         jreq.parse(req);
 
         UniValue result = rpcServer.ExecuteCommand(config, jreq);
         rpc_result = JSONRPCReplyObj(result, NullUniValue, jreq.id);
     } catch (const UniValue &objError) {
         rpc_result = JSONRPCReplyObj(NullUniValue, objError, jreq.id);
     } catch (const std::exception &e) {
         rpc_result = JSONRPCReplyObj(
             NullUniValue, JSONRPCError(RPC_PARSE_ERROR, e.what()), jreq.id);
     }
 
     return rpc_result;
 }
 
 std::string JSONRPCExecBatch(Config &config, RPCServer &rpcServer,
                              const JSONRPCRequest &jreq, const UniValue &vReq) {
     UniValue ret(UniValue::VARR);
     for (size_t i = 0; i < vReq.size(); i++) {
         ret.push_back(JSONRPCExecOne(config, rpcServer, jreq, vReq[i]));
     }
 
     return ret.write() + "\n";
 }
 
 /**
  * Process named arguments into a vector of positional arguments, based on the
  * passed-in specification for the RPC call's arguments.
  */
 static inline JSONRPCRequest
 transformNamedArguments(const JSONRPCRequest &in,
                         const std::vector<std::string> &argNames) {
     JSONRPCRequest out = in;
     out.params = UniValue(UniValue::VARR);
     // Build a map of parameters, and remove ones that have been processed, so
     // that we can throw a focused error if there is an unknown one.
     const std::vector<std::string> &keys = in.params.getKeys();
     const std::vector<UniValue> &values = in.params.getValues();
     std::unordered_map<std::string, const UniValue *> argsIn;
     for (size_t i = 0; i < keys.size(); ++i) {
         argsIn[keys[i]] = &values[i];
     }
     // Process expected parameters.
     int hole = 0;
     for (const std::string &argNamePattern : argNames) {
         std::vector<std::string> vargNames;
         boost::algorithm::split(vargNames, argNamePattern,
                                 boost::algorithm::is_any_of("|"));
         auto fr = argsIn.end();
         for (const std::string &argName : vargNames) {
             fr = argsIn.find(argName);
             if (fr != argsIn.end()) {
                 break;
             }
         }
         if (fr != argsIn.end()) {
             for (int i = 0; i < hole; ++i) {
                 // Fill hole between specified parameters with JSON nulls, but
                 // not at the end (for backwards compatibility with calls that
                 // act based on number of specified parameters).
                 out.params.push_back(UniValue());
             }
             hole = 0;
             out.params.push_back(*fr->second);
             argsIn.erase(fr);
         } else {
             hole += 1;
         }
     }
     // If there are still arguments in the argsIn map, this is an error.
     if (!argsIn.empty()) {
         throw JSONRPCError(RPC_INVALID_PARAMETER,
                            "Unknown named parameter " + argsIn.begin()->first);
     }
     // Return request with named arguments transformed to positional arguments
     return out;
 }
 
 UniValue CRPCTable::execute(Config &config,
                             const JSONRPCRequest &request) const {
     // Return immediately if in warmup
     {
         LOCK(cs_rpcWarmup);
         if (fRPCInWarmup) {
             throw JSONRPCError(RPC_IN_WARMUP, rpcWarmupStatus);
         }
     }
 
     // Find method
     auto it = mapCommands.find(request.strMethod);
     if (it != mapCommands.end()) {
         UniValue result;
         for (const auto &command : it->second) {
             if (ExecuteCommand(config, *command, request, result,
                                &command == &it->second.back())) {
                 return result;
             }
         }
     }
     throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
 }
 
 static bool ExecuteCommand(Config &config, const CRPCCommand &command,
                            const JSONRPCRequest &request, UniValue &result,
                            bool last_handler) {
     try {
         RPCCommandExecution execution(request.strMethod);
         // Execute, convert arguments to array if necessary
         if (request.params.isObject()) {
             return command.actor(
                 config, transformNamedArguments(request, command.argNames),
                 result, last_handler);
         } else {
             return command.actor(config, request, result, last_handler);
         }
     } catch (const std::exception &e) {
         throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }
 }
 
 std::vector<std::string> CRPCTable::listCommands() const {
     std::vector<std::string> commandList;
     for (const auto &i : mapCommands) {
         commandList.emplace_back(i.first);
     }
     return commandList;
 }
 
 void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface) {
     if (!timerInterface) {
         timerInterface = iface;
     }
 }
 
 void RPCSetTimerInterface(RPCTimerInterface *iface) {
     timerInterface = iface;
 }
 
 void RPCUnsetTimerInterface(RPCTimerInterface *iface) {
     if (timerInterface == iface) {
         timerInterface = nullptr;
     }
 }
 
 void RPCRunLater(const std::string &name, std::function<void()> func,
                  int64_t nSeconds) {
     if (!timerInterface) {
         throw JSONRPCError(RPC_INTERNAL_ERROR,
                            "No timer handler registered for RPC");
     }
     LOCK(g_deadline_timers_mutex);
     deadlineTimers.erase(name);
     LogPrint(BCLog::RPC, "queue run of timer %s in %i seconds (using %s)\n",
              name, nSeconds, timerInterface->Name());
     deadlineTimers.emplace(
         name, std::unique_ptr<RPCTimerBase>(
                   timerInterface->NewTimer(func, nSeconds * 1000)));
 }
 
 int RPCSerializationFlags() {
     return 0;
 }
 
 CRPCTable tableRPC;
diff --git a/src/support/lockedpool.cpp b/src/support/lockedpool.cpp
index 26e8d99b1..f20cf3aca 100644
--- a/src/support/lockedpool.cpp
+++ b/src/support/lockedpool.cpp
@@ -1,411 +1,410 @@
 // Copyright (c) 2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <support/cleanse.h>
 #include <support/lockedpool.h>
 
 #if defined(HAVE_CONFIG_H)
 #include <config/bitcoin-config.h>
 #endif
 
 #ifdef WIN32
 #ifndef NOMINMAX
 #define NOMINMAX
 #endif
 #include <windows.h>
 #else
 #include <climits>        // for PAGESIZE
 #include <sys/mman.h>     // for mmap
 #include <sys/resource.h> // for getrlimit
 #include <unistd.h>       // for sysconf
 #endif
 
 #include <algorithm>
 #ifdef ARENA_DEBUG
 #include <iomanip>
 #include <iostream>
 #endif
 
 LockedPoolManager *LockedPoolManager::_instance = nullptr;
-std::once_flag LockedPoolManager::init_flag;
 
 /*******************************************************************************/
 // Utilities
 //
 /** Align up to power of 2 */
 static inline size_t align_up(size_t x, size_t align) {
     return (x + align - 1) & ~(align - 1);
 }
 
 /*******************************************************************************/
 // Implementation: Arena
 
 Arena::Arena(void *base_in, size_t size_in, size_t alignment_in)
     : base(static_cast<char *>(base_in)),
       end(static_cast<char *>(base_in) + size_in), alignment(alignment_in) {
     // Start with one free chunk that covers the entire arena
     auto it = size_to_free_chunk.emplace(size_in, base);
     chunks_free.emplace(base, it);
     chunks_free_end.emplace(base + size_in, it);
 }
 
 Arena::~Arena() {}
 
 void *Arena::alloc(size_t size) {
     // Round to next multiple of alignment
     size = align_up(size, alignment);
 
     // Don't handle zero-sized chunks
     if (size == 0) {
         return nullptr;
     }
 
     // Pick a large enough free-chunk. Returns an iterator pointing to the first
     // element that is not less than key. This allocation strategy is best-fit.
     // According to "Dynamic Storage Allocation: A Survey and Critical Review",
     // Wilson et. al. 1995,
     // http://www.scs.stanford.edu/14wi-cs140/sched/readings/wilson.pdf,
     // best-fit and first-fit policies seem to work well in practice.
     auto size_ptr_it = size_to_free_chunk.lower_bound(size);
     if (size_ptr_it == size_to_free_chunk.end()) {
         return nullptr;
     }
 
     // Create the used-chunk, taking its space from the end of the free-chunk
     const size_t size_remaining = size_ptr_it->first - size;
     auto alloced =
         chunks_used.emplace(size_ptr_it->second + size_remaining, size).first;
     chunks_free_end.erase(size_ptr_it->second + size_ptr_it->first);
     if (size_ptr_it->first == size) {
         // whole chunk is used up
         chunks_free.erase(size_ptr_it->second);
     } else {
         // still some memory left in the chunk
         auto it_remaining =
             size_to_free_chunk.emplace(size_remaining, size_ptr_it->second);
         chunks_free[size_ptr_it->second] = it_remaining;
         chunks_free_end.emplace(size_ptr_it->second + size_remaining,
                                 it_remaining);
     }
     size_to_free_chunk.erase(size_ptr_it);
 
     return reinterpret_cast<void *>(alloced->first);
 }
 
 void Arena::free(void *ptr) {
     // Freeing the nullptr pointer is OK.
     if (ptr == nullptr) {
         return;
     }
 
     // Remove chunk from used map
     auto i = chunks_used.find(static_cast<char *>(ptr));
     if (i == chunks_used.end()) {
         throw std::runtime_error("Arena: invalid or double free");
     }
     std::pair<char *, size_t> freed = *i;
     chunks_used.erase(i);
 
     // coalesce freed with previous chunk
     auto prev = chunks_free_end.find(freed.first);
     if (prev != chunks_free_end.end()) {
         freed.first -= prev->second->first;
         freed.second += prev->second->first;
         size_to_free_chunk.erase(prev->second);
         chunks_free_end.erase(prev);
     }
 
     // coalesce freed with chunk after freed
     auto next = chunks_free.find(freed.first + freed.second);
     if (next != chunks_free.end()) {
         freed.second += next->second->first;
         size_to_free_chunk.erase(next->second);
         chunks_free.erase(next);
     }
 
     // Add/set space with coalesced free chunk
     auto it = size_to_free_chunk.emplace(freed.second, freed.first);
     chunks_free[freed.first] = it;
     chunks_free_end[freed.first + freed.second] = it;
 }
 
 Arena::Stats Arena::stats() const {
     Arena::Stats r{0, 0, 0, chunks_used.size(), chunks_free.size()};
     for (const auto &chunk : chunks_used) {
         r.used += chunk.second;
     }
     for (const auto &chunk : chunks_free) {
         r.free += chunk.second->first;
     }
     r.total = r.used + r.free;
     return r;
 }
 
 #ifdef ARENA_DEBUG
 static void printchunk(void *base, size_t sz, bool used) {
     std::cout << "0x" << std::hex << std::setw(16) << std::setfill('0') << base
               << " 0x" << std::hex << std::setw(16) << std::setfill('0') << sz
               << " 0x" << used << std::endl;
 }
 void Arena::walk() const {
     for (const auto &chunk : chunks_used) {
         printchunk(chunk.first, chunk.second, true);
     }
     std::cout << std::endl;
     for (const auto &chunk : chunks_free) {
         printchunk(chunk.first, chunk.second->first, false);
     }
     std::cout << std::endl;
 }
 #endif
 
 /*******************************************************************************/
 // Implementation: Win32LockedPageAllocator
 
 #ifdef WIN32
 /**
  * LockedPageAllocator specialized for Windows.
  */
 class Win32LockedPageAllocator : public LockedPageAllocator {
 public:
     Win32LockedPageAllocator();
     void *AllocateLocked(size_t len, bool *lockingSuccess) override;
     void FreeLocked(void *addr, size_t len) override;
     size_t GetLimit() override;
 
 private:
     size_t page_size;
 };
 
 Win32LockedPageAllocator::Win32LockedPageAllocator() {
     // Determine system page size in bytes
     SYSTEM_INFO sSysInfo;
     GetSystemInfo(&sSysInfo);
     page_size = sSysInfo.dwPageSize;
 }
 void *Win32LockedPageAllocator::AllocateLocked(size_t len,
                                                bool *lockingSuccess) {
     len = align_up(len, page_size);
     void *addr =
         VirtualAlloc(nullptr, len, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
     if (addr) {
         // VirtualLock is used to attempt to keep keying material out of swap.
         // Note that it does not provide this as a guarantee, but, in practice,
         // memory that has been VirtualLock'd almost never gets written to the
         // pagefile except in rare circumstances where memory is extremely low.
         *lockingSuccess = VirtualLock(const_cast<void *>(addr), len) != 0;
     }
     return addr;
 }
 void Win32LockedPageAllocator::FreeLocked(void *addr, size_t len) {
     len = align_up(len, page_size);
     memory_cleanse(addr, len);
     VirtualUnlock(const_cast<void *>(addr), len);
 }
 
 size_t Win32LockedPageAllocator::GetLimit() {
     // TODO is there a limit on Windows, how to get it?
     return std::numeric_limits<size_t>::max();
 }
 #endif
 
 /*******************************************************************************/
 // Implementation: PosixLockedPageAllocator
 
 #ifndef WIN32
 /**
  * LockedPageAllocator specialized for OSes that don't try to be special
  * snowflakes.
  */
 class PosixLockedPageAllocator : public LockedPageAllocator {
 public:
     PosixLockedPageAllocator();
     void *AllocateLocked(size_t len, bool *lockingSuccess) override;
     void FreeLocked(void *addr, size_t len) override;
     size_t GetLimit() override;
 
 private:
     size_t page_size;
 };
 
 PosixLockedPageAllocator::PosixLockedPageAllocator() {
 // Determine system page size in bytes
 #if defined(PAGESIZE) // defined in climits
     page_size = PAGESIZE;
 #else // assume some POSIX OS
     page_size = sysconf(_SC_PAGESIZE);
 #endif
 }
 
 // Some systems (at least OS X) do not define MAP_ANONYMOUS yet and define
 // MAP_ANON which is deprecated
 #ifndef MAP_ANONYMOUS
 #define MAP_ANONYMOUS MAP_ANON
 #endif
 
 void *PosixLockedPageAllocator::AllocateLocked(size_t len,
                                                bool *lockingSuccess) {
     void *addr;
     len = align_up(len, page_size);
     addr = mmap(nullptr, len, PROT_READ | PROT_WRITE,
                 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     if (addr == MAP_FAILED) {
         return nullptr;
     }
     if (addr) {
         *lockingSuccess = mlock(addr, len) == 0;
 #if defined(MADV_DONTDUMP) // Linux
         madvise(addr, len, MADV_DONTDUMP);
 #elif defined(MADV_NOCORE) // FreeBSD
         madvise(addr, len, MADV_NOCORE);
 #endif
     }
     return addr;
 }
 void PosixLockedPageAllocator::FreeLocked(void *addr, size_t len) {
     len = align_up(len, page_size);
     memory_cleanse(addr, len);
     munlock(addr, len);
     munmap(addr, len);
 }
 size_t PosixLockedPageAllocator::GetLimit() {
 #ifdef RLIMIT_MEMLOCK
     struct rlimit rlim;
     if (getrlimit(RLIMIT_MEMLOCK, &rlim) == 0) {
         if (rlim.rlim_cur != RLIM_INFINITY) {
             return rlim.rlim_cur;
         }
     }
 #endif
     return std::numeric_limits<size_t>::max();
 }
 #endif
 
 /*******************************************************************************/
 // Implementation: LockedPool
 
 LockedPool::LockedPool(std::unique_ptr<LockedPageAllocator> allocator_in,
                        LockingFailed_Callback lf_cb_in)
     : allocator(std::move(allocator_in)), lf_cb(lf_cb_in),
       cumulative_bytes_locked(0) {}
 
 LockedPool::~LockedPool() {}
 void *LockedPool::alloc(size_t size) {
     std::lock_guard<std::mutex> lock(mutex);
 
     // Don't handle impossible sizes
     if (size == 0 || size > ARENA_SIZE) {
         return nullptr;
     }
 
     // Try allocating from each current arena
     for (auto &arena : arenas) {
         void *addr = arena.alloc(size);
         if (addr) {
             return addr;
         }
     }
     // If that fails, create a new one
     if (new_arena(ARENA_SIZE, ARENA_ALIGN)) {
         return arenas.back().alloc(size);
     }
     return nullptr;
 }
 
 void LockedPool::free(void *ptr) {
     std::lock_guard<std::mutex> lock(mutex);
     // TODO we can do better than this linear search by keeping a map of arena
     // extents to arena, and looking up the address.
     for (auto &arena : arenas) {
         if (arena.addressInArena(ptr)) {
             arena.free(ptr);
             return;
         }
     }
     throw std::runtime_error(
         "LockedPool: invalid address not pointing to any arena");
 }
 
 LockedPool::Stats LockedPool::stats() const {
     std::lock_guard<std::mutex> lock(mutex);
     LockedPool::Stats r{0, 0, 0, cumulative_bytes_locked, 0, 0};
     for (const auto &arena : arenas) {
         Arena::Stats i = arena.stats();
         r.used += i.used;
         r.free += i.free;
         r.total += i.total;
         r.chunks_used += i.chunks_used;
         r.chunks_free += i.chunks_free;
     }
     return r;
 }
 
 bool LockedPool::new_arena(size_t size, size_t align) {
     bool locked;
     // If this is the first arena, handle this specially: Cap the upper size by
     // the process limit. This makes sure that the first arena will at least be
     // locked. An exception to this is if the process limit is 0: in this case
     // no memory can be locked at all so we'll skip past this logic.
     if (arenas.empty()) {
         size_t limit = allocator->GetLimit();
         if (limit > 0) {
             size = std::min(size, limit);
         }
     }
     void *addr = allocator->AllocateLocked(size, &locked);
     if (!addr) {
         return false;
     }
     if (locked) {
         cumulative_bytes_locked += size;
     } else if (lf_cb) {
         // Call the locking-failed callback if locking failed
         if (!lf_cb()) {
             // If the callback returns false, free the memory and fail,
             // otherwise consider the user warned and proceed.
             allocator->FreeLocked(addr, size);
             return false;
         }
     }
     arenas.emplace_back(allocator.get(), addr, size, align);
     return true;
 }
 
 LockedPool::LockedPageArena::LockedPageArena(LockedPageAllocator *allocator_in,
                                              void *base_in, size_t size_in,
                                              size_t align_in)
     : Arena(base_in, size_in, align_in), base(base_in), size(size_in),
       allocator(allocator_in) {}
 LockedPool::LockedPageArena::~LockedPageArena() {
     allocator->FreeLocked(base, size);
 }
 
 /*******************************************************************************/
 // Implementation: LockedPoolManager
 //
 LockedPoolManager::LockedPoolManager(
     std::unique_ptr<LockedPageAllocator> allocator_in)
     : LockedPool(std::move(allocator_in), &LockedPoolManager::LockingFailed) {}
 
 bool LockedPoolManager::LockingFailed() {
     // TODO: log something but how? without including util.h
     return true;
 }
 
 void LockedPoolManager::CreateInstance() {
 // Using a local static instance guarantees that the object is initialized when
 // it's first needed and also deinitialized after all objects that use it are
 // done with it. I can think of one unlikely scenario where we may have a static
 // deinitialization order/problem, but the check in LockedPoolManagerBase's
 // destructor helps us detect if that ever happens.
 #ifdef WIN32
     std::unique_ptr<LockedPageAllocator> allocator(
         new Win32LockedPageAllocator());
 #else
     std::unique_ptr<LockedPageAllocator> allocator(
         new PosixLockedPageAllocator());
 #endif
     static LockedPoolManager instance(std::move(allocator));
     LockedPoolManager::_instance = &instance;
 }
diff --git a/src/support/lockedpool.h b/src/support/lockedpool.h
index 102fc956c..036c9b3cb 100644
--- a/src/support/lockedpool.h
+++ b/src/support/lockedpool.h
@@ -1,254 +1,253 @@
 // Copyright (c) 2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_SUPPORT_LOCKEDPOOL_H
 #define BITCOIN_SUPPORT_LOCKEDPOOL_H
 
 #include <cstdint>
 #include <list>
 #include <map>
 #include <memory>
 #include <mutex>
 #include <unordered_map>
 
 /**
  * OS-dependent allocation and deallocation of locked/pinned memory pages.
  * Abstract base class.
  */
 class LockedPageAllocator {
 public:
     virtual ~LockedPageAllocator() {}
     /**
      * Allocate and lock memory pages.
      * If len is not a multiple of the system page size, it is rounded up.
      * Returns nullptr in case of allocation failure.
      *
      * If locking the memory pages could not be accomplished it will still
      * return the memory, however the lockingSuccess flag will be false.
      * lockingSuccess is undefined if the allocation fails.
      */
     virtual void *AllocateLocked(size_t len, bool *lockingSuccess) = 0;
 
     /**
      * Unlock and free memory pages.
      * Clear the memory before unlocking.
      */
     virtual void FreeLocked(void *addr, size_t len) = 0;
 
     /**
      * Get the total limit on the amount of memory that may be locked by this
      * process, in bytes. Return size_t max if there is no limit or the limit is
      * unknown. Return 0 if no memory can be locked at all.
      */
     virtual size_t GetLimit() = 0;
 };
 
 /**
  * An arena manages a contiguous region of memory by dividing it into chunks.
  */
 class Arena {
 public:
     Arena(void *base, size_t size, size_t alignment);
     virtual ~Arena();
 
     Arena(const Arena &other) = delete;       // non construction-copyable
     Arena &operator=(const Arena &) = delete; // non copyable
 
     /** Memory statistics. */
     struct Stats {
         size_t used;
         size_t free;
         size_t total;
         size_t chunks_used;
         size_t chunks_free;
     };
 
     /**
      * Allocate size bytes from this arena.
      * Returns pointer on success, or 0 if memory is full or the application
      * tried to allocate 0 bytes.
      */
     void *alloc(size_t size);
 
     /**
      * Free a previously allocated chunk of memory.
      * Freeing the zero pointer has no effect.
      * Raises std::runtime_error in case of error.
      */
     void free(void *ptr);
 
     /** Get arena usage statistics */
     Stats stats() const;
 
 #ifdef ARENA_DEBUG
     void walk() const;
 #endif
 
     /**
      * Return whether a pointer points inside this arena.
      * This returns base <= ptr < (base+size) so only use it for (inclusive)
      * chunk starting addresses.
      */
     bool addressInArena(void *ptr) const { return ptr >= base && ptr < end; }
 
 private:
     typedef std::multimap<size_t, char *> SizeToChunkSortedMap;
     /** Map to enable O(log(n)) best-fit allocation, as it's sorted by size */
     SizeToChunkSortedMap size_to_free_chunk;
 
     typedef std::unordered_map<char *, SizeToChunkSortedMap::const_iterator>
         ChunkToSizeMap;
     /** Map from begin of free chunk to its node in size_to_free_chunk */
     ChunkToSizeMap chunks_free;
     /** Map from end of free chunk to its node in size_to_free_chunk */
     ChunkToSizeMap chunks_free_end;
 
     /** Map from begin of used chunk to its size */
     std::unordered_map<char *, size_t> chunks_used;
 
     /** Base address of arena */
     char *base;
     /** End address of arena */
     char *end;
     /** Minimum chunk alignment */
     size_t alignment;
 };
 
 /**
  * Pool for locked memory chunks.
  *
  * To avoid sensitive key data from being swapped to disk, the memory in this
  * pool is locked/pinned.
  *
  * An arena manages a contiguous region of memory. The pool starts out with one
  * arena but can grow to multiple arenas if the need arises.
  *
  * Unlike a normal C heap, the administrative structures are separate from the
  * managed memory. This has been done as the sizes and bases of objects are not
  * in themselves sensitive information, as to conserve precious locked memory.
  * In some operating systems the amount of memory that can be locked is small.
  */
 class LockedPool {
 public:
     /**
      * Size of one arena of locked memory. This is a compromise.
      * Do not set this too low, as managing many arenas will increase allocation
      * and deallocation overhead. Setting it too high allocates more locked
      * memory from the OS than strictly necessary.
      */
     static const size_t ARENA_SIZE = 256 * 1024;
     /**
      * Chunk alignment. Another compromise. Setting this too high will waste
      * memory, setting it too low will facilitate fragmentation.
      */
     static const size_t ARENA_ALIGN = 16;
 
     /**
      * Callback when allocation succeeds but locking fails.
      */
     typedef bool (*LockingFailed_Callback)();
 
     /** Memory statistics. */
     struct Stats {
         size_t used;
         size_t free;
         size_t total;
         size_t locked;
         size_t chunks_used;
         size_t chunks_free;
     };
 
     /**
      * Create a new LockedPool. This takes ownership of the MemoryPageLocker,
      * you can only instantiate this with LockedPool(std::move(...)).
      *
      * The second argument is an optional callback when locking a newly
      * allocated arena failed. If this callback is provided and returns false,
      * the allocation fails (hard fail), if it returns true the allocation
      * proceeds, but it could warn.
      */
     explicit LockedPool(std::unique_ptr<LockedPageAllocator> allocator,
                         LockingFailed_Callback lf_cb_in = nullptr);
     ~LockedPool();
 
     LockedPool(const LockedPool &other) = delete; // non construction-copyable
     LockedPool &operator=(const LockedPool &) = delete; // non copyable
 
     /**
      * Allocate size bytes from this arena.
      * Returns pointer on success, or 0 if memory is full or the application
      * tried to allocate 0 bytes.
      */
     void *alloc(size_t size);
 
     /**
      * Free a previously allocated chunk of memory.
      * Freeing the zero pointer has no effect.
      * Raises std::runtime_error in case of error.
      */
     void free(void *ptr);
 
     /** Get pool usage statistics */
     Stats stats() const;
 
 private:
     std::unique_ptr<LockedPageAllocator> allocator;
 
     /** Create an arena from locked pages */
     class LockedPageArena : public Arena {
     public:
         LockedPageArena(LockedPageAllocator *alloc_in, void *base_in,
                         size_t size, size_t align);
         ~LockedPageArena();
 
     private:
         void *base;
         size_t size;
         LockedPageAllocator *allocator;
     };
 
     bool new_arena(size_t size, size_t align);
 
     std::list<LockedPageArena> arenas;
     LockingFailed_Callback lf_cb;
     size_t cumulative_bytes_locked;
     /**
      * Mutex protects access to this pool's data structures, including arenas.
      */
     mutable std::mutex mutex;
 };
 
 /**
  * Singleton class to keep track of locked (ie, non-swappable) memory, for use
  * in std::allocator templates.
  *
  * Some implementations of the STL allocate memory in some constructors (i.e.,
  * see MSVC's vector<T> implementation where it allocates 1 byte of memory in
  * the allocator). Due to the unpredictable order of static initializers, we
  * have to make sure the LockedPoolManager instance exists before any other
  * STL-based objects that use secure_allocator are created. So instead of having
  * LockedPoolManager also be static-initialized, it is created on demand.
  */
 class LockedPoolManager : public LockedPool {
 public:
     /** Return the current instance, or create it once */
     static LockedPoolManager &Instance() {
-        std::call_once(LockedPoolManager::init_flag,
-                       LockedPoolManager::CreateInstance);
+        static std::once_flag init_flag;
+        std::call_once(init_flag, LockedPoolManager::CreateInstance);
         return *LockedPoolManager::_instance;
     }
 
 private:
     explicit LockedPoolManager(std::unique_ptr<LockedPageAllocator> allocator);
 
     /** Create a new LockedPoolManager specialized to the OS */
     static void CreateInstance();
     /** Called when locking fails, warn the user here */
     static bool LockingFailed();
 
     static LockedPoolManager *_instance;
-    static std::once_flag init_flag;
 };
 
 #endif // BITCOIN_SUPPORT_LOCKEDPOOL_H