mirror_zfs/tests/zfs-tests/cmd/file/file_fadvise.c
Finix1979 320f0c6022
Add Linux posix_fadvise support
The purpose of this PR is to accepts fadvise ioctl from userland
to do read-ahead by demand.

It could dramatically improve sequential read performance especially
when primarycache is set to metadata or zfs_prefetch_disable is 1.

If the file is mmaped, generic_fadvise is also called for page cache
read-ahead besides dmu_prefetch.

Only POSIX_FADV_WILLNEED and POSIX_FADV_SEQUENTIAL are supported in
this PR currently.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Finix Yan <yancw@info2soft.com>
Closes #13694
2022-09-08 10:29:41 -07:00

98 lines
2.0 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2022 by Information2 Software, Inc. All rights reserved.
*/
#include "file_common.h"
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
/*
* Call fadvise to prefetch data
*/
static const char *execname = "file_fadvise";
static void
usage(void)
{
(void) fprintf(stderr,
"usage: %s -f filename -a advise \n", execname);
}
int
main(int argc, char *argv[])
{
char *filename = NULL;
int advise = 0;
int fd, ch;
int err = 0;
while ((ch = getopt(argc, argv, "a:f:")) != EOF) {
switch (ch) {
case 'a':
advise = atoll(optarg);
break;
case 'f':
filename = optarg;
break;
case '?':
(void) printf("unknown arg %c\n", optopt);
usage();
break;
}
}
if (!filename) {
(void) printf("Filename not specified (-f <file>)\n");
err++;
}
if (advise < POSIX_FADV_NORMAL || advise > POSIX_FADV_NOREUSE) {
(void) printf("advise is invalid\n");
err++;
}
if (err) {
usage(); /* no return */
return (1);
}
if ((fd = open(filename, O_RDWR, 0666)) < 0) {
perror("open");
return (1);
}
posix_fadvise(fd, 0, 0, advise);
close(fd);
return (0);
}