1 /*

     2  * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 #include "jni.h"

    27 #include "jni_util.h"

    28 #include "jvm.h"

    29 #include "jlong.h"

    30 #include "java_nio_MappedByteBuffer.h"

    31 #include <stdlib.h>

    32 

    33 JNIEXPORT jboolean JNICALL

    34 Java_java_nio_MappedByteBuffer_isLoaded0(JNIEnv *env, jobject obj,

    35                                         jlong address, jlong len)

    36 {

    37     jboolean loaded = JNI_FALSE;

    38     /* Information not available?

    39     MEMORY_BASIC_INFORMATION info;

    40     void *a = (void *) jlong_to_ptr(address);

    41     int result = VirtualQuery(a, &info, (DWORD)len);

    42     */

    43     return loaded;

    44 }

    45 

    46 JNIEXPORT jint JNICALL

    47 Java_java_nio_MappedByteBuffer_load0(JNIEnv *env, jobject obj, jlong address,

    48                                      jlong len, jint pageSize)

    49 {

    50     int *ptr = (int *) jlong_to_ptr(address);

    51     int pageIncrement = pageSize / sizeof(int);

    52     jlong numPages = (len + pageSize - 1) / pageSize;

    53     int i = 0;

    54     int j = 0;

    55 

    56     /* touch every page */

    57     for (i=0; i<numPages; i++) {

    58         j += *((volatile int *)ptr);

    59         ptr += pageIncrement;

    60     }

    61     return j;

    62 }

    63 

    64 JNIEXPORT void JNICALL

    65 Java_java_nio_MappedByteBuffer_force0(JNIEnv *env, jobject obj, jlong address,

    66                                       jlong len)

    67 {

    68     void *a = (void *) jlong_to_ptr(address);

    69     int result;

    70     int retry;

    71 

    72     /*

    73      * FlushViewOfFile can fail with ERROR_LOCK_VIOLATION if the memory

    74      * system is writing dirty pages to disk. As there is no way to

    75      * synchronize the flushing then we retry a limited number of times.

    76      */

    77     retry = 0;

    78     do {

    79         result = FlushViewOfFile(a, (DWORD)len);

    80         if ((result != 0) || (GetLastError() != ERROR_LOCK_VIOLATION))

    81             break;

    82         retry++;

    83     } while (retry < 3);

    84 

    85     if (result == 0) {

    86         JNU_ThrowIOExceptionWithLastError(env, "Flush failed");

    87     }

    88 }