Create shared memory "files" on Windows. These "files" will be

allocated directly by the OS in the paging file (the HUGE file
that cannot be defragmented with any tools). Unlike UNIX, they
do not have physical existence as files.

This commit was SVN r11273.

ompi/mca/common/sm/common_sm_mmap.c

@@ -42,6 +42,7 @@
 
 #include "ompi/constants.h"
 #include "common_sm_mmap.h"
+#include "opal/util/basename.h"
 #include "opal/util/output.h"
 #include "orte/util/sys_info.h"
 #include "orte/util/proc_info.h"
@@ -88,14 +89,15 @@ mca_common_sm_mmap_t* mca_common_sm_mmap_init(size_t size, char *file_name,
         size_t size_ctl_structure, size_t data_seg_alignment)
 {
     int fd = -1, return_code = OMPI_SUCCESS;
-    bool file_previously_opened;
+    bool file_previously_opened = false;
     mca_common_sm_file_header_t* seg = NULL;
     mca_common_sm_mmap_t* map = NULL;
-    struct stat s_stat;
     unsigned char *addr = NULL;
     size_t tmp,mem_offset;
 
 #if !defined(__WINDOWS__)
+    struct stat s_stat;
+
     /* input parameter error checks */
     if( (size < sizeof(mca_common_sm_file_header_t) ) ||
                 ( file_name == NULL ) || 
@@ -147,34 +149,48 @@ mca_common_sm_mmap_t* mca_common_sm_mmap_init(size_t size, char *file_name,
 #else
     HANDLE hMapObject = INVALID_HANDLE_VALUE;
     LPVOID lpvMem = NULL;
+    char *temp1, *temp2;
+    int rc;
 
+    /**
+     * On Windows the shared file will be created by the OS directly on
+     * the system ressources. Therefore, no file get involved in the
+     * operation. However, a unique key should be used as name for the
+     * shared memory object in order to allow all processes to access
+     * the same unique shared memory region. The key will be obtained
+     * from the original file_name by replacing all path separator
+     * occurences by '/' (as '\' is not allowed on the object name).
+     */
+    temp1 = strdup(file_name);
+    temp2 = temp1;
+    while( NULL != (temp2 = strchr(temp2, OPAL_PATH_SEP[0])) ) {
+        *temp2 = '/';
+    }
     hMapObject = CreateFileMapping( INVALID_HANDLE_VALUE, /* use paging file */
                                     NULL,                 /* no security attributes */
                                     PAGE_READWRITE,       /* read/write access */
                                     0,                    /* size: high 32-bits */
                                     size,                 /* size: low 32-bits */
-                                    file_name);           /* name of map object */
-    if( ERROR_ALREADY_EXISTS == GetLastError() )
-        file_previously_opened=true;
-
-    if( NULL != hMapObject ) {
-        /* Get a pointer to the file-mapped shared memory. */
-        lpvMem = MapViewOfFile( hMapObject,     /* object to map view of */
-                                FILE_MAP_WRITE, /* read/write access */
-                                0,              /* high offset:  map from */
-                                0,              /* low offset:   beginning */
-                                0);             /* default: map entire file */
-    }
-    seg = (mca_common_sm_file_header_t*)lpvMem;
-    if( NULL == lpvMem ) {
-        int rc = GetLastError();
-        char* localbuf = NULL;
-        FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
-                       NULL, rc, 0, (LPTSTR)&localbuf, 1024, NULL );
-        opal_output( 0, "%s\n", localbuf );
-        LocalFree( localbuf );
+                                    temp1);               /* name of map object */
+    if( NULL == hMapObject ) {
+        rc = GetLastError();
         goto return_error;
     }
+    if( ERROR_ALREADY_EXISTS == GetLastError() )
+        file_previously_opened=true;
+    free(temp1);  /* relase the temporary file name */
+
+    /* Get a pointer to the file-mapped shared memory. */
+    lpvMem = MapViewOfFile( hMapObject,          /* object to map view of */
+                            FILE_MAP_WRITE,      /* read/write access */
+                            0,                   /* high offset:  map from */
+                            0,                   /* low offset:   beginning */
+                            0);                  /* default: map entire file */
+    if( NULL == lpvMem ) {
+        rc = GetLastError();
+        goto return_error;
+    }
+    seg = (mca_common_sm_file_header_t*)lpvMem;
 #endif  /* !defined(__WINDOWS__) */
 
     /* set up the map object */
@@ -184,6 +200,7 @@ mca_common_sm_mmap_t* mca_common_sm_mmap_init(size_t size, char *file_name,
        entry in the control structure is an mca_common_sm_file_header_t
        element */
     map->map_seg = seg;
+    map->hMappedObject = hMapObject;
 
     /* If we have a data segment (i.e., if 0 != data_seg_alignment),
        then make it the first aligned address after the control
@@ -227,8 +244,6 @@ mca_common_sm_mmap_t* mca_common_sm_mmap_init(size_t size, char *file_name,
         goto return_error;
     }
     close(fd);
-#else
-    CloseHandle(hMapObject);
 #endif  /* !defined(__WINDOWS__) */
 
     return map;
@@ -241,6 +256,13 @@ mca_common_sm_mmap_t* mca_common_sm_mmap_init(size_t size, char *file_name,
     }
     if( NULL != seg ) munmap((void*) seg,size);
 #else
+    {
+        char* localbuf = NULL;
+        FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
+                       NULL, rc, 0, (LPTSTR)&localbuf, 1024, NULL );
+        opal_output( 0, "%s\n", localbuf );
+        LocalFree( localbuf );
+    }
     if( NULL != lpvMem ) UnmapViewOfFile( lpvMem );
     if( NULL != hMapObject ) CloseHandle(hMapObject);
 #endif  /* !defined(__WINDOWS__) */
@@ -262,6 +284,8 @@ int mca_common_sm_mmap_fini( mca_common_sm_mmap_t* sm_mmap )
         if( false == return_error ) {
             rc = GetLastError();
         }
+        CloseHandle(sm_mmap->hMappedObject);
+
 #endif  /* !defined(__WINDOWS__) */
     }
     return rc;

ompi/mca/common/sm/common_sm_mmap.h

@@ -66,6 +66,9 @@ struct mca_common_sm_mmap_t {
     unsigned char  *data_addr;
     size_t map_size;
     char map_path[OMPI_PATH_MAX];
+#if defined(__WINDOWS__)
+    HANDLE hMappedObject;
+#endif  /* defined(__WINDOWS__) */
 };
 typedef struct mca_common_sm_mmap_t mca_common_sm_mmap_t;