ec1c3bce45
Add support for Direct I/O in FileChannel Co-authored-by: Volker Simonis <volker.simonis@gmail.com> Reviewed-by: alanb, bpb, alanbur, coffeys, aph, clanger, plevart, mli, psandoz, simonis
104 lines
3.1 KiB
C
104 lines
3.1 KiB
C
/*
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* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* Test if a file exists in the file system cache
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*/
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include "jni.h"
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/*
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* Throws an exception with the given class name and detail message
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*/
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static void ThrowException(JNIEnv *env, const char *name, const char *msg) {
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jclass cls = (*env)->FindClass(env, name);
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if (cls != NULL) {
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(*env)->ThrowNew(env, cls, msg);
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}
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}
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/*
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* Class: DirectIO
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* Method: isFileInCache0
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* Signature: (ILjava/lang/String;)Z
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*/
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JNIEXPORT jboolean Java_DirectIOTest_isFileInCache0(JNIEnv *env,
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jclass cls,
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jint file_size,
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jstring file_path) {
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void *f_mmap;
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#ifdef __linux__
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unsigned char *f_seg;
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#else
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char *f_seg;
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#endif
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#ifdef __APPLE__
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size_t mask = MINCORE_INCORE;
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#else
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size_t mask = 0x1;
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#endif
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size_t page_size = getpagesize();
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size_t index = (file_size + page_size - 1) /page_size;
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jboolean result = JNI_FALSE;
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const char* path = (*env)->GetStringUTFChars(env, file_path, JNI_FALSE);
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int fd = open(path, O_RDWR);
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(*env)->ReleaseStringUTFChars(env, file_path, path);
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f_mmap = mmap(0, file_size, PROT_NONE, MAP_SHARED, fd, 0);
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if (f_mmap == MAP_FAILED) {
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close(fd);
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ThrowException(env, "java/io/IOException",
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"test of whether file exists in cache failed");
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}
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f_seg = malloc(index);
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if (f_seg != NULL) {
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if(mincore(f_mmap, file_size, f_seg) == 0) {
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size_t i;
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for (i = 0; i < index; i++) {
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if (f_seg[i] & mask) {
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result = JNI_TRUE;
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break;
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}
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}
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}
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free(f_seg);
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} else {
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ThrowException(env, "java/io/IOException",
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"test of whether file exists in cache failed");
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}
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close(fd);
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munmap(f_mmap, file_size);
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return result;
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}
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