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このサンプル・プログラムは， 第 4 章 で説明したメモリ管理 VLM 機能を紹介します。

/* ***************************************************************************** * * Copyright (c) Digital Equipment Corporation, 1996 All Rights Reserved. * Unpublished rights reserved under the copyright laws of the United States. * * The software contained on this media is proprietary to and embodies the * confidential technology of Digital Equipment Corporation. Possession, use, * duplication or dissemination of the software and media is authorized only * pursuant to a valid written license from Digital Equipment Corporation. * * RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the U.S. * Government is subject to restrictions as set forth in Subparagraph * (c)(1)(ii) of DFARS 252.227-7013, or in FAR 52.227-19, as applicable. * ***************************************************************************** /* This program creates and maps to a memory resident global section using shared page tables. The program requires a reserved memory entry (named In_Memory_Database) in the Reserved Memory Registry. The entry in the registry is created using SYSMAN as follows: $ MCR SYSMAN SYSMAN> RESERVED_MEMORY ADD "In_Memory_Database"/ALLOCATE/PAGE_TABLES - /ZERO/SIZE=64/GROUP=100 The above command creates an entry named In_Memory_Database that is 64 Mbytes in size and requests that the physical memory be allocated during system initialization. This enables the physcial memory to be mapped with granularity hints by the SYS$CRMPSC_GDZRO_64 system service. It also requests that physical memory be allocated for page tables for the named entry, requests the allocated memory be zeroed, and requests that UIC group number 100 be associated with the entry. Once the entry has been created with SYSMAN, the system must be re-tuned with AUTOGEN. Doing so allows AUTOGEN to re-calculate values for SYSGEN parameters that are sensitive to changes in physical memory sizes. (Recall that the Reserved Memory Registry takes physical pages away from the system.) Once AUTOGEN has been run, the system must be rebooted. Using the following commands to compile and link this program: $ CC/POINTER_SIZE=32 shared_page_tables_example $ LINK shared_page_tables_example Since 64-bit virtual addresses are used by this program, a Version 5.2 DEC C compiler or later is required to compile it. */ #define __NEW_STARLET 1 #include <DESCRIP> #include <FAR_POINTERS> #include <GEN64DEF> #include <INTS> #include <PSLDEF> #include <SECDEF> #include <SSDEF> #include <STARLET> #include <STDIO> #include <STDLIB> #include <STRING> #include <VADEF> #define bad_status(status) (((status) & 1) != 1) #define ONE_MEGABYTE 0x100000  main () { int status; $DESCRIPTOR (section_name, "In_Memory_Database"); uint32 region_flags = VA$M_SHARED_PTS, /* Shared PT region. */ section_flags = SEC$M_EXPREG; uint64 mapped_length, requested_size = 64*ONE_MEGABYTE, section_length = 64*ONE_MEGABYTE, region_length; GENERIC_64 region_id; VOID_PQ mapped_va, region_start_va; printf ("Shared Page Table Region Creation Attempt: Size = %0Ld\n", requested_size); /* Create a shared page table region. */ status = sys$create_region_64 ( requested_size, /* Size in bytes of region */ VA$C_REGION_UCREATE_UOWN, /* Region VA creation and owner mode */ region_flags, /* Region Flags: shared page tables */ &region_id, /* Region ID */ &region_start_va, /* Starting VA for region */ &region_length); /* Size of created region */ if (bad_status (status)) { printf ("ERROR: Unable to create region of size %16Ld\n\n", requested_size); return; } printf ("Shared Page Table Region Created: VA = %016LX, Size = %0Ld\n\n", region_start_va, region_length); /* Create and map a memory resident section with shared page tables into the shared page table region. */ printf ("Create and map to section %s\n", section_name.dsc$a_pointer); status = sys$crmpsc_gdzro_64 ( &section_name, /* Section name */ 0, /* Section Ident */ 0, /* Section protection */ section_length, /* Length of Section */ &region_id, /* RDE */ 0, /* Section Offset; map entire section */ PSL$C_USER, /* Access Mode */ section_flags, /* Section Creation Flags */ &mapped_va, /* Return VA */ &mapped_length); /* Return Mapped Length */ if (bad_status (status)) printf ("ERROR: Unable to Create and Map Section %s, status = %08x\n\n", section_name.dsc$a_pointer, status); else { printf ("Section %s created, Section Length = %0Ld\n", section_name.dsc$a_pointer, section_length); printf (" Mapped VA = %016LX, Mapped Length = %0Ld\n\n", mapped_va, mapped_length); } /* Delete the shared page table. This will cause the mapping to the section and the section itself to be deleted. */ printf ("Delete the mapping to the memory resident global section"); printf (" and the shared\n page table region.\n"); status = sys$delete_region_64 ( &region_id, PSL$C_USER, &region_start_va, &region_length); if (bad_status (status)) printf ("ERROR: Unable to delete shared page table region, status = %08x\n\n", status); else printf ("Region Deleted, Start VA = %016LX, Length = %016LX\n\n", region_start_va, region_length); printf ("\n"); }

This example program displays the following output:

Shared Page Table Region Creation Attempt: Size = 67108864 Shared Page Table Region Created: VA = FFFFFFFBFC000000, Size = 67108864 Create and map to section In_Memory_Database Section In_Memory_Database created, Section Length = 67108864 Mapped VA = FFFFFFFBFC000000, Mapped Length = 67108864 Delete the mapping to the memory resident global section and the shared page table region. Region Deleted, Start VA = FFFFFFFBFC000000, Length = 0000000004000000

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