X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/ff872033c735b70f6cd0da4ee36cc8998d8e0acd..bf71c3c42ec41053cf17711276bfd40d9b3a93c1:/src/smpi/smpi_shared.cpp

diff --git a/src/smpi/smpi_shared.cpp b/src/smpi/smpi_shared.cpp
index ee0687d029..cd4b82093e 100644
--- a/src/smpi/smpi_shared.cpp
+++ b/src/smpi/smpi_shared.cpp
@@ -38,7 +38,6 @@
 
 #include "private.h"
 #include "private.hpp"
-#include "smpi/smpi_shared_malloc.hpp"
 #include "xbt/dict.h"
 #include "xbt/ex.hpp"
 #include <errno.h>
@@ -87,7 +86,7 @@ public:
     return filename_length == that.filename_length && line == that.line &&
            std::memcmp(filename, that.filename, filename_length) == 0;
   }
-  bool operator!=(smpi_source_location const& that) const { return !(*this == that); }
+  bool operator!=(smpi_source_location const& that) const { return not(*this == that); }
 };
 }
 
@@ -215,18 +214,24 @@ static void *smpi_shared_malloc_local(size_t size, const char *file, int line)
 
 #define HUGE_PAGE_SIZE 1<<21
 
-/*
- * Similar to smpi_shared_malloc, but only sharing the blocks described by shared_block_offsets.
+/* Similar to smpi_shared_malloc, but only sharing the blocks described by shared_block_offsets.
  * This array contains the offsets (in bytes) of the block to share.
  * Even indices are the start offsets (included), odd indices are the stop offsets (excluded).
- * For instance, if shared_block_offsets == {27, 42}, then the elements mem[27], mem[28], ..., mem[41] are shared. The others are not.
+ * For instance, if shared_block_offsets == {27, 42}, then the elements mem[27], mem[28], ..., mem[41] are shared.
+ * The others are not.
  */
+
 void* smpi_shared_malloc_partial(size_t size, size_t* shared_block_offsets, int nb_shared_blocks)
 {
   char *huge_page_mount_point = xbt_cfg_get_string("smpi/shared-malloc-hugepage");
-  const bool use_huge_page = huge_page_mount_point[0] != '\0';
+  bool use_huge_page = huge_page_mount_point[0] != '\0';
+#ifndef MAP_HUGETLB /* If the system header don't define that mmap flag */
+  xbt_assert(not use_huge_page,
+             "Huge pages are not available on your system, you cannot use the smpi/shared-malloc-hugepage option.");
+  use_huge_page = 0;
+#endif
   smpi_shared_malloc_blocksize = static_cast<unsigned long>(xbt_cfg_get_double("smpi/shared-malloc-blocksize"));
-  void *mem, *allocated_ptr;
+  void* mem;
   size_t allocated_size;
   if(use_huge_page) {
     xbt_assert(smpi_shared_malloc_blocksize == HUGE_PAGE_SIZE, "the block size of shared malloc should be equal to the size of a huge page.");
@@ -239,13 +244,11 @@ void* smpi_shared_malloc_partial(size_t size, size_t* shared_block_offsets, int
 
 
   /* First reserve memory area */
-  allocated_ptr = mmap(NULL, allocated_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-
+  void* allocated_ptr = mmap(NULL, allocated_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 
   xbt_assert(allocated_ptr != MAP_FAILED, "Failed to allocate %zuMiB of memory. Run \"sysctl vm.overcommit_memory=1\" as root "
                                 "to allow big allocations.\n",
              size >> 20);
-
   if(use_huge_page)
     mem = (void*)ALIGN_UP((uint64_t)allocated_ptr, HUGE_PAGE_SIZE);
   else
@@ -254,7 +257,12 @@ void* smpi_shared_malloc_partial(size_t size, size_t* shared_block_offsets, int
   XBT_DEBUG("global shared allocation. Blocksize %lu", smpi_shared_malloc_blocksize);
   /* Create a fd to a new file on disk, make it smpi_shared_malloc_blocksize big, and unlink it.
    * It still exists in memory but not in the file system (thus it cannot be leaked). */
-  /* Create bogus file if not done already */
+  /* Create bogus file if not done already
+   * We need two different bogusfiles:
+   *    smpi_shared_malloc_bogusfile_huge_page is used for calls to mmap *with* MAP_HUGETLB,
+   *    smpi_shared_malloc_bogusfile is used for calls to mmap *without* MAP_HUGETLB.
+   * We cannot use a same file for the two type of calls, since the first one needs to be
+   * opened in a hugetlbfs mount point whereas the second needs to be a "classical" file. */
   if(use_huge_page && smpi_shared_malloc_bogusfile_huge_page == -1) {
     const char *const array[] = {huge_page_mount_point, "simgrid-shmalloc-XXXXXX", nullptr};
     char *huge_page_filename = xbt_str_join_array(array, "/");
@@ -279,8 +287,10 @@ void* smpi_shared_malloc_partial(size_t size, size_t* shared_block_offsets, int
   int mmap_base_flag = MAP_FIXED | MAP_SHARED | MAP_POPULATE;
   int mmap_flag = mmap_base_flag;
   int huge_fd = use_huge_page ? smpi_shared_malloc_bogusfile_huge_page : smpi_shared_malloc_bogusfile;
+#ifdef MAP_HUGETLB
   if(use_huge_page)
     mmap_flag |= MAP_HUGETLB;
+#endif
 
   XBT_DEBUG("global shared allocation, begin mmap");