1 /*
   2  * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef OS_LINUX_GLOBALS_LINUX_HPP
  26 #define OS_LINUX_GLOBALS_LINUX_HPP
  27 
  28 //
  29 // Declare Linux specific flags. They are not available on other platforms.
  30 //
  31 #include "runtime/flags/jvmFlag.hpp"
  32 PRODUCT_FLAG(bool,     UseOprofile, false, JVMFlag::DEFAULT,
  33                        "enable support for Oprofile profiler");
  34 
  35 
  36     //   NB: The default value of UseLinuxPosixThreadCPUClocks may be   
  37     //  overridden in Arguments::parse_each_vm_init_arg.                
  38 PRODUCT_FLAG(bool,     UseLinuxPosixThreadCPUClocks, true, JVMFlag::DEFAULT,
  39                        "enable fast Linux Posix clocks where available");
  40 
  41 PRODUCT_FLAG(bool,     UseHugeTLBFS, false, JVMFlag::DEFAULT,
  42                        "Use MAP_HUGETLB for large pages");
  43 
  44 PRODUCT_FLAG(bool,     UseTransparentHugePages, false, JVMFlag::DEFAULT,
  45                        "Use MADV_HUGEPAGE for large pages");
  46 
  47 PRODUCT_FLAG(bool,     LoadExecStackDllInVMThread, true, JVMFlag::DEFAULT,
  48                        "Load DLLs with executable-stack attribute in the VM Thread");
  49 
  50 PRODUCT_FLAG(bool,     UseSHM, false, JVMFlag::DEFAULT,
  51                        "Use SYSV shared memory for large pages");
  52 
  53 PRODUCT_FLAG(bool,     UseContainerSupport, true, JVMFlag::DEFAULT,
  54                        "Enable detection and runtime container configuration support");
  55 
  56 PRODUCT_FLAG(bool,     PreferContainerQuotaForCPUCount, true, JVMFlag::DEFAULT,
  57                        "Calculate the container CPU availability based on the value"
  58                        " of quotas (if set), when true. Otherwise, use the CPU"
  59                        " shares value, provided it is less than quota.");
  60 
  61 PRODUCT_FLAG(bool,     AdjustStackSizeForTLS, false, JVMFlag::DEFAULT,
  62                        "Increase the thread stack size to include space for glibc "
  63                        "static thread-local storage (TLS) if true");
  64 
  65 PRODUCT_FLAG(bool,     DumpPrivateMappingsInCore, true, JVMFlag::DIAGNOSTIC,
  66                        "If true, sets bit 2 of /proc/PID/coredump_filter, thus "
  67                        "resulting in file-backed private mappings of the process to "
  68                        "be dumped into the corefile.");
  69 
  70 PRODUCT_FLAG(bool,     DumpSharedMappingsInCore, true, JVMFlag::DIAGNOSTIC,
  71                        "If true, sets bit 3 of /proc/PID/coredump_filter, thus "
  72                        "resulting in file-backed shared mappings of the process to "
  73                        "be dumped into the corefile.");
  74 
  75 PRODUCT_FLAG(bool,     UseCpuAllocPath, false, JVMFlag::DIAGNOSTIC,
  76                        "Use CPU_ALLOC code path in os::active_processor_count ");
  77 
  78 //
  79 // Define Linux-specific default values. The flags are available on all
  80 // platforms, but they may have different default values on other platforms.
  81 //
  82 define_pd_global(bool, UseLargePages, false);
  83 define_pd_global(bool, UseLargePagesIndividualAllocation, false);
  84 define_pd_global(bool, UseOSErrorReporting, false);
  85 define_pd_global(bool, UseThreadPriorities, true) ;
  86 
  87 #endif // OS_LINUX_GLOBALS_LINUX_HPP