[issue 1164] Oom handling

src/search/planner.cc

@@ -44,19 +44,41 @@ int main(int argc, const char **argv) {
             parse_cmd_line(argc, argv, unit_cost);
 
         utils::Timer search_timer;
-        search_algorithm->search();
-        search_timer.stop();
-        utils::g_timer.stop();
-
-        search_algorithm->save_plan_if_necessary();
-        search_algorithm->print_statistics();
-        utils::g_log << "Search time: " << search_timer << endl;
-        utils::g_log << "Total time: " << utils::g_timer << endl;
-
-        ExitCode exitcode = search_algorithm->found_solution()
-                                ? ExitCode::SUCCESS
-                                : ExitCode::SEARCH_UNSOLVED_INCOMPLETE;
-        exit_with(exitcode);
+
+	try {
+	    search_algorithm->search();
+	} catch (const utils::ExitException &e) {
+
+	    /* To ensure that all destructors are called before the program exits,
+	       we raise an exception in utils::exit_with() and let main() return. */
+
+	    // this branch happens only when ExitException is thrown inside search().
+
+	    search_timer.stop();
+	    utils::g_timer.stop();
+
+	    // NOTE: The following code may cons because it uses ostreams and strings.
+	    // We currently reserve the space for it with memory padding inside register_event_handlers (1MB).
+	    // TODO: make them reentrant.
+	    search_algorithm->print_statistics();
+	    utils::g_log << "Search time: " << search_timer << endl;
+	    utils::g_log << "Total time: " << utils::g_timer << endl;
+
+	    return static_cast<int>(e.get_exitcode());
+	}
+
+	search_timer.stop();
+	utils::g_timer.stop();
+
+	search_algorithm->save_plan_if_necessary();
+	search_algorithm->print_statistics();
+	utils::g_log << "Search time: " << search_timer << endl;
+	utils::g_log << "Total time: " << utils::g_timer << endl;
+
+	ExitCode exitcode = search_algorithm->found_solution()
+	    ? ExitCode::SUCCESS
+	    : ExitCode::SEARCH_UNSOLVED_INCOMPLETE;
+	exit_with(exitcode);
     } catch (const utils::ExitException &e) {
         /* To ensure that all destructors are called before the program exits,
            we raise an exception in utils::exit_with() and let main() return. */

src/search/utils/system_unix.cc

@@ -42,6 +42,10 @@
 using namespace std;
 
 namespace utils {
+
+static void* emergency_reserve = nullptr;
+static const std::size_t reserve_size = 1024 * 1024; // 1MB
+
 static void write_reentrant(int filedescr, const char *message, int len) {
     while (len > 0) {
         int written;
@@ -164,8 +168,21 @@ static void out_of_memory_handler() {
       memory is not sufficient, we can consider using sigaltstack to reserve
       memory for the stack of the signal handler and raising a signal here.
     */
-    write_reentrant_str(STDOUT_FILENO, "Failed to allocate memory.\n");
-    exit_with_reentrant(ExitCode::SEARCH_OUT_OF_MEMORY);
+    // Above is an old comment. The old behavior immediately went to the else branch.
+    // Instead of exiting immediately, we free the padding memory,
+    // throw utils::ExitException, catch it in main, and exit gracefully.
+    // Throwing and catching the exception unwinds the stack, which ensures running the destructors.
+    // Masataro Asai 2026/03/05
+    if (emergency_reserve) {
+        std::free(emergency_reserve);
+        emergency_reserve = nullptr;
+	write_reentrant_str(STDOUT_FILENO, "Failed to allocate memory.\n");
+	write_reentrant_str(STDOUT_FILENO, "Trying to exit gracefully.\n");
+	exit_with(ExitCode::SEARCH_OUT_OF_MEMORY);
+    } else {
+	write_reentrant_str(STDOUT_FILENO, "Failed to allocate memory (second time). Exiting.\n");
+	exit_with_reentrant(ExitCode::SEARCH_OUT_OF_MEMORY);
+    }
 }
 
 static void signal_handler(int signal_number) {
@@ -223,6 +240,8 @@ int get_peak_memory_in_kb() {
 }
 
 void register_event_handlers() {
+    emergency_reserve = std::malloc(reserve_size);
+
     // Terminate when running out of memory.
     set_new_handler(out_of_memory_handler);