Improve chainbase mapped and heap behavior

docs/01_nodeos/03_plugins/chain_plugin/index.md

@@ -163,10 +163,14 @@ Config Options for eosio::chain_plugin:
                                         headers signed by it will be fully
                                         validated, but transactions in those
                                         validated blocks will be trusted.
-  --database-map-mode arg (=mapped)     Database map mode ("mapped", "heap", or
-                                        "locked").
+  --database-map-mode arg (=mapped)     Database map mode ("mapped",
+                                        "mapped_private", "heap", or "locked").
                                         In "mapped" mode database is memory
                                         mapped as a file.
+                                        In "mapped_private" mode database is
+                                        memory mapped as a file using a private
+                                        mapping (no disk writeback until
+                                        program exit).
                                         In "heap" mode database is preloaded in
                                         to swappable memory and will use huge
                                         pages if available.

libraries/chain/controller.cpp

@@ -37,6 +37,7 @@
 
 #include <new>
 #include <shared_mutex>
+#include <utility>
 
 namespace eosio { namespace chain {
 
@@ -591,6 +592,7 @@ struct controller_impl {
       EOS_ASSERT( snapshot, snapshot_exception, "No snapshot reader provided" );
       this->shutdown = shutdown;
       try {
+         auto snapshot_load_start_time = fc::time_point::now();
          snapshot->validate();
          if( auto blog_head = blog.head() ) {
             ilog( "Starting initialization from snapshot and block log ${b}-${e}, this may take a significant amount of time",
@@ -606,8 +608,11 @@ struct controller_impl {
          }
          ilog( "Snapshot loaded, lib: ${lib}", ("lib", head->block_num) );
 
-         init(check_shutdown);
-         ilog( "Finished initialization from snapshot" );
+         init(std::move(check_shutdown));
+         if (conf.revert_to_private_mode)
+            db.revert_to_private_mode();
+         auto snapshot_load_time = (fc::time_point::now() - snapshot_load_start_time).to_seconds();
+         ilog( "Finished initialization from snapshot (snapshot load time was ${t}s)", ("t", snapshot_load_time) );
       } catch (boost::interprocess::bad_alloc& e) {
          elog( "Failed initialization from snapshot - db storage not configured to have enough storage for the provided snapshot, please increase and retry snapshot" );
          shutdown();
@@ -622,7 +627,7 @@ struct controller_impl {
                   ("genesis_chain_id", genesis_chain_id)("controller_chain_id", chain_id)
       );
 
-      this->shutdown = shutdown;
+      this->shutdown = std::move(shutdown);
       if( fork_db.head() ) {
          if( read_mode == db_read_mode::IRREVERSIBLE && fork_db.head()->id != fork_db.root()->id ) {
             fork_db.rollback_head_to_root();
@@ -644,14 +649,14 @@ struct controller_impl {
       } else {
          blog.reset( genesis, head->block );
       }
-      init(check_shutdown);
+      init(std::move(check_shutdown));
    }
 
    void startup(std::function<void()> shutdown, std::function<bool()> check_shutdown) {
       EOS_ASSERT( db.revision() >= 1, database_exception, "This version of controller::startup does not work with a fresh state database." );
       EOS_ASSERT( fork_db.head(), fork_database_exception, "No existing fork database despite existing chain state. Replay required." );
 
-      this->shutdown = shutdown;
+      this->shutdown = std::move(shutdown);
       uint32_t lib_num = fork_db.root()->block_num;
       auto first_block_num = blog.first_block_num();
       if( auto blog_head = blog.head() ) {
@@ -674,7 +679,7 @@ struct controller_impl {
       }
       head = fork_db.head();
 
-      init(check_shutdown);
+      init(std::move(check_shutdown));
    }
 
 
@@ -3475,9 +3480,16 @@ void controller::validate_tapos( const transaction& trx )const { try {
 } FC_CAPTURE_AND_RETHROW() }
 
 void controller::validate_db_available_size() const {
-   const auto free = db().get_segment_manager()->get_free_memory();
+   const auto free = db().get_free_memory();
    const auto guard = my->conf.state_guard_size;
    EOS_ASSERT(free >= guard, database_guard_exception, "database free: ${f}, guard size: ${g}", ("f", free)("g",guard));
+
+   // give a change to chainbase to write some pages to disk if memory becomes scarce.
+   if (is_write_window()) {
+      if (auto flushed_pages = mutable_db().check_memory_and_flush_if_needed()) {
+         ilog("CHAINBASE: flushed ${p} pages to disk to decrease memory pressure", ("p", flushed_pages));
+      }
+   }
 }
 
 bool controller::is_protocol_feature_activated( const digest_type& feature_digest )const {

libraries/chain/include/eosio/chain/controller.hpp

@@ -79,6 +79,7 @@ namespace eosio { namespace chain {
             bool                     disable_replay_opts    =  false;
             bool                     contracts_console      =  false;
             bool                     allow_ram_billing_in_notify = false;
+            bool                     revert_to_private_mode =  false;
             uint32_t                 maximum_variable_signature_length = chain::config::default_max_variable_signature_length;
             bool                     disable_all_subjective_mitigations = false; //< for developer & testing purposes, can be configured using `disable-all-subjective-mitigations` when `EOSIO_DEVELOPER` build option is provided
             uint32_t                 terminate_at_block     = 0;

plugins/chain_plugin/chain_plugin.cpp

@@ -345,8 +345,9 @@ void chain_plugin::set_program_options(options_description& cli, options_descrip
           "Subjectively limit the maximum length of variable components in a variable legnth signature to this size in bytes")
          ("trusted-producer", bpo::value<vector<string>>()->composing(), "Indicate a producer whose blocks headers signed by it will be fully validated, but transactions in those validated blocks will be trusted.")
          ("database-map-mode", bpo::value<chainbase::pinnable_mapped_file::map_mode>()->default_value(chainbase::pinnable_mapped_file::map_mode::mapped),
-          "Database map mode (\"mapped\", \"heap\", or \"locked\").\n"
+          "Database map mode (\"mapped\", \"mapped_private\", \"heap\", or \"locked\").\n"
           "In \"mapped\" mode database is memory mapped as a file.\n"
+          "In \"mapped_private\" mode database is memory mapped as a file using a private mapping (no disk writeback until program exit).\n"
 #ifndef _WIN32
           "In \"heap\" mode database is preloaded in to swappable memory and will use huge pages if available.\n"
           "In \"locked\" mode database is preloaded, locked in to memory, and will use huge pages if available.\n"
@@ -934,6 +935,13 @@ void chain_plugin_impl::plugin_initialize(const variables_map& options) {
 
       chain_config->db_map_mode = options.at("database-map-mode").as<pinnable_mapped_file::map_mode>();
 
+      // when loading a snapshot, all the state will be modified, so temporarily use the `mapped` mode instead
+      // of `mapped_private` to lower memory requirements.
+      if (snapshot_path && chain_config->db_map_mode == pinnable_mapped_file::mapped_private) {
+        chain_config->db_map_mode = pinnable_mapped_file::mapped;
+        chain_config->revert_to_private_mode = true; // revert to `mapped_private` mode after loading snapshot.
+      }
+
 #ifdef EOSIO_EOS_VM_OC_RUNTIME_ENABLED
       if( options.count("eos-vm-oc-cache-size-mb") )
          chain_config->eosvmoc_config.cache_size = options.at( "eos-vm-oc-cache-size-mb" ).as<uint64_t>() * 1024u * 1024u;

programs/leap-util/actions/snapshot.cpp

@@ -103,7 +103,7 @@ int snapshot_actions::run_subcommand() {
       snap_out.flush();
       snap_out.close();
    } catch(const database_guard_exception& e) {
-      std::cerr << "Database is not configured to have enough storage to handle provided snapshot, please increase storage and try aagain" << std::endl;
+      std::cerr << "Database is not configured to have enough storage to handle provided snapshot, please increase storage and try again" << std::endl;
       control.reset();
       throw;
    }