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freebsd/config/kernel-fadvise.m4
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

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dnl #
dnl # Linux 4.19 API
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_FADVISE], [
ZFS_LINUX_TEST_SRC([file_fadvise], [
#include <linux/fs.h>
static const struct file_operations
fops __attribute__ ((unused)) = {
.fadvise = NULL,
};
],[])
])
AC_DEFUN([ZFS_AC_KERNEL_FADVISE], [
AC_MSG_CHECKING([whether fops->fadvise() exists])
ZFS_LINUX_TEST_RESULT([file_fadvise], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_FILE_FADVISE, 1, [fops->fadvise() exists])
],[
AC_MSG_RESULT(no)
])
])