src/hotspot/os/linux/trimCHeapDCmd.cpp

/*
 * Copyright (c) 2022 SAP SE. All rights reserved.
 * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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#include "logging/log.hpp"
#include "runtime/os.inline.hpp"
#include "trimCHeapDCmd.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/ostream.hpp"

#include <malloc.h>

void TrimCLibcHeapDCmd::execute(DCmdSource source, TRAPS) {
  if (os::can_trim_native_heap()) {
    os::size_change_t sc;
    if (os::trim_native_heap(&sc)) {
      _output->print("Trim native heap: ");
      if (sc.after != SIZE_MAX) {
        const size_t delta = sc.after < sc.before ? (sc.before - sc.after) : (sc.after - sc.before);
        const char sign = sc.after < sc.before ? '-' : '+';
        _output->print_cr("RSS+Swap: " PROPERFMT "->" PROPERFMT " (%c" PROPERFMT ")",
                          PROPERFMTARGS(sc.before), PROPERFMTARGS(sc.after), sign, PROPERFMTARGS(delta));
        // Also log if native trim log is active
        log_info(trimnative)("Manual Trim: " PROPERFMT "->" PROPERFMT " (%c" PROPERFMT ")",
                             PROPERFMTARGS(sc.before), PROPERFMTARGS(sc.after), sign, PROPERFMTARGS(delta));
      } else {
        _output->print_cr("(no details available).");
      }
    }
  } else {
    _output->print_cr("Not available.");
  }
}