text: /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
  /*
   * Copyright (c) 2004-2008 The Trustees of Indiana University and Indiana
   *                         University Research and Technology
   *                         Corporation.  All rights reserved.
   * Copyright (c) 2004-2005 The University of Tennessee and The University
   *                         of Tennessee Research Foundation.  All rights
   *                         reserved.
   * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
   *                         University of Stuttgart.  All rights reserved.
   * Copyright (c) 2004-2005 The Regents of the University of California.
   *                         All rights reserved.
   * Copyright (c) 2007-2015 Cisco Systems, Inc.  All rights reserved.
   * Copyright (c) 2010-2015 Los Alamos National Security, LLC. All rights
   *                         reserved.
   * Copyright (c) 2016-2019 Intel, Inc.  All rights reserved.
   * $COPYRIGHT$
   *
   * Additional copyrights may follow
   *
   * $HEADER$
   *
   * These symbols are in a file by themselves to provide nice linker
   * semantics.  Since linkers generally pull in symbols by object
   * files, keeping these symbols as the only symbols in this file
   * prevents utility programs such as "ompi_info" from having to import
   * entire components just to query their version and parameters.
   */
  
  #include "opal_config.h"
  
  #include "opal/constants.h"
  #include "opal/mca/shmem/shmem.h"
  #include "shmem_mmap.h"
  
  /**
   * public string showing the shmem ompi_mmap component version number
   */
  const char *opal_shmem_mmap_component_version_string =
      "OPAL mmap shmem MCA component version " OPAL_VERSION;
  
  int opal_shmem_mmap_relocate_backing_file = 0;
  char *opal_shmem_mmap_backing_file_base_dir = NULL;
  bool opal_shmem_mmap_nfs_warning = true;
  
  /**
   * local functions
   */
  static int mmap_register(void);
  static int mmap_open(void);
  static int mmap_close(void);
  static int mmap_query(mca_base_module_t **module, int *priority);
  static int mmap_runtime_query(mca_base_module_t **module,
                                int *priority,
                                const char *hint);
  
  /**
   * instantiate the public struct with all of our public information
   * and pointers to our public functions in it
   */
  opal_shmem_mmap_component_t mca_shmem_mmap_component = {
      .super = {
          .base_version = {
              OPAL_SHMEM_BASE_VERSION_2_0_0,
  
              /* component name and version */
              .mca_component_name = "mmap",
              MCA_BASE_MAKE_VERSION(component, OPAL_MAJOR_VERSION, OPAL_MINOR_VERSION,
                                    OPAL_RELEASE_VERSION),
  
              .mca_open_component = mmap_open,
              .mca_close_component = mmap_close,
              .mca_query_component = mmap_query,
              .mca_register_component_params = mmap_register,
          },
          /* MCA v2.0.0 component meta data */
          .base_data = {
              /* the component is checkpoint ready */
              MCA_BASE_METADATA_PARAM_CHECKPOINT
          },
          .runtime_query = mmap_runtime_query,
      },
  };
  
  /* ////////////////////////////////////////////////////////////////////////// */
  static int
  mmap_runtime_query(mca_base_module_t **module,
                     int *priority,
                     const char *hint)
  {
      /* no run-time query needed for mmap, so this is easy */
      *priority = mca_shmem_mmap_component.priority;
      *module = (mca_base_module_t *)&opal_shmem_mmap_module.super;
      return OPAL_SUCCESS;
  }
  
  static int
  mmap_register(void)
  {
      int ret;
  
  
      /* ////////////////////////////////////////////////////////////////////// */
      /* (default) priority - set high to make mmap the default */
      mca_shmem_mmap_component.priority = 50;
      ret = mca_base_component_var_register (&mca_shmem_mmap_component.super.base_version,
                                             "priority", "Priority for shmem mmap "
                                             "component (default: 50)", MCA_BASE_VAR_TYPE_INT,
                                             NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
                                             OPAL_INFO_LVL_3,
                                             MCA_BASE_VAR_SCOPE_ALL_EQ,
                                             &mca_shmem_mmap_component.priority);
  
      /*
       * Do we want the "warning: your mmap file is on NFS!" message?  Per a
       * thread on the OMPI devel list
       * (http://www.open-mpi.org/community/lists/devel/2011/12/10054.php),
       * on some systems, it doesn't seem to matter.  But per older threads,
       * it definitely does matter on some systems.  Perhaps newer kernels
       * are smarter about this kind of stuff...?  Regardless, we should
       * provide the ability to turn off this message for systems where the
       * effect doesn't matter.
       */
      opal_shmem_mmap_nfs_warning = true;
      ret = mca_base_component_var_register (&mca_shmem_mmap_component.super.base_version,
                                             "enable_nfs_warning",
                                             "Enable the warning emitted when Open MPI detects "
                                             "that its shared memory backing file is located on "
                                             "a network filesystem (1 = enabled, 0 = disabled).",
                                             MCA_BASE_VAR_TYPE_BOOL, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
                                             OPAL_INFO_LVL_9, MCA_BASE_VAR_SCOPE_LOCAL,
                                             &opal_shmem_mmap_nfs_warning);
      if (0 > ret) {
          return ret;
      }
  
      opal_shmem_mmap_relocate_backing_file = 0;
      ret = mca_base_component_var_register (&mca_shmem_mmap_component.super.base_version,
                                             "relocate_backing_file",
                                             "Whether to change the default placement of backing files or not "
                                             "(Negative = try to relocate backing files to an area rooted at "
                                             "the path specified by "
                                             "shmem_mmap_backing_file_base_dir, but continue "
                                             "with the default path if the relocation fails, 0 = do not relocate, "
                                             "Positive = same as the negative option, but will fail if the "
                                             "relocation fails.", MCA_BASE_VAR_TYPE_INT, NULL, 0,
                                             MCA_BASE_VAR_FLAG_SETTABLE, OPAL_INFO_LVL_9,
                                             MCA_BASE_VAR_SCOPE_ALL_EQ, &opal_shmem_mmap_relocate_backing_file);
      if (0 > ret) {
          return ret;
      }
  
      opal_shmem_mmap_backing_file_base_dir = "/dev/shm";
      ret = mca_base_component_var_register (&mca_shmem_mmap_component.super.base_version,
                                             "backing_file_base_dir",
                                             "Specifies where backing files will be created when "
                                             "shmem_mmap_relocate_backing_file is in use.", MCA_BASE_VAR_TYPE_STRING,
                                             NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE, OPAL_INFO_LVL_9,
                                             MCA_BASE_VAR_SCOPE_ALL_EQ,
                                             &opal_shmem_mmap_backing_file_base_dir);
      if (0 > ret) {
          return ret;
      }
  
      return OPAL_SUCCESS;
  }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  static int
  mmap_open(void)
  {
      return OPAL_SUCCESS;
  }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  static int
  mmap_query(mca_base_module_t **module, int *priority)
  {
      *priority = mca_shmem_mmap_component.priority;
      *module = (mca_base_module_t *)&opal_shmem_mmap_module.super;
      return OPAL_SUCCESS;
  }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  static int
  mmap_close(void)
  {
      return OPAL_SUCCESS;
  }
  
  