1 /*
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   3  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
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  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
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  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
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  25 
  26 #ifndef OS_AIX_GLOBALS_AIX_HPP
  27 #define OS_AIX_GLOBALS_AIX_HPP
  28 
  29 //
  30 // Defines Aix specific flags. They are not available on other platforms.
  31 //
  32 // (Please keep the switches sorted alphabetically.)
  33 #define RUNTIME_OS_FLAGS(develop, \
  34                          develop_pd, \
  35                          product, \
  36                          product_pd, \
  37                          diagnostic, \
  38                          diagnostic_pd, \
  39                          notproduct, \
  40                          range, \
  41                          constraint, \
  42                          writeable) \
  43                                                                                     \
  44   /* Whether to allow the VM to run if EXTSHM=ON. EXTSHM is an environment */       \
  45   /* variable used on AIX to activate certain hacks which allow more shm segments */\
  46   /* for 32bit processes. For 64bit processes, it is pointless and may have */      \
  47   /* harmful side effects (e.g. for some reasonn prevents allocation of 64k pages */\
  48   /* via shmctl). */                                                                \
  49   /* Per default we quit with an error if that variable is found; for certain */    \
  50   /* customer scenarios, we may want to be able to run despite that variable. */    \
  51   product(bool, AllowExtshm, false,                                                 \
  52           "Allow VM to run with EXTSHM=ON.")                                        \
  53                                                                                     \
  54   /*  Maximum expected size of the data segment. That correlates with the      */   \
  55   /*  to the maximum C Heap consumption we expect.                             */   \
  56   /*  We need to know this because we need to leave "breathing space" for the  */   \
  57   /*  data segment when placing the java heap. If that space is too small, we  */   \
  58   /*  reduce our chance of getting a low heap address (needed for compressed   */   \
  59   /*  Oops).                                                                   */   \
  60   product(uintx, MaxExpectedDataSegmentSize, 8*G,                                   \
  61           "Maximum expected Data Segment Size.")                                    \
  62                                                                                     \
  63   /* Use optimized addresses for the polling page.                             */   \
  64   product(bool, OptimizePollingPageLocation, true,                                  \
  65              "Optimize the location of the polling page used for Safepoints")       \
  66                                                                                     \
  67   /* Use 64K pages for virtual memory (shmat). */                                   \
  68   product(bool, Use64KPages, true,                                                  \
  69           "Use 64K pages if available.")                                            \
  70                                                                                     \
  71   /*  If VM uses 64K paged memory (shmat) for virtual memory: threshold below  */   \
  72   /*  which virtual memory allocations are done with 4K memory (mmap). This is */   \
  73   /*  mainly for test purposes.                                                */   \
  74   develop(uintx, Use64KPagesThreshold, 0,                                           \
  75           "4K/64K page allocation threshold.")                                      \
  76                                                                                     \
  77   /* Normally AIX commits memory on touch, but sometimes it is helpful to have */   \
  78   /* explicit commit behaviour. This flag, if true, causes the VM to touch     */   \
  79   /* memory on os::commit_memory() (which normally is a noop).                 */   \
  80   product(bool, UseExplicitCommit, false,                                           \
  81           "Explicit commit for virtual memory.")                                    \
  82                                                                                     \
  83 
  84 
  85 //
  86 // Defines Aix-specific default values. The flags are available on all
  87 // platforms, but they may have different default values on other platforms.
  88 //
  89 
  90 // UseLargePages means nothing, for now, on AIX.
  91 // Use Use64KPages or Use16MPages instead.
  92 define_pd_global(bool, UseLargePages, false);
  93 define_pd_global(bool, UseLargePagesIndividualAllocation, false);
  94 define_pd_global(bool, UseOSErrorReporting, false);
  95 define_pd_global(bool, UseThreadPriorities, true) ;
  96 
  97 #endif // OS_AIX_GLOBALS_AIX_HPP