320f0c6022
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
28 lines
787 B
Plaintext
28 lines
787 B
Plaintext
dnl #
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dnl # 5.3 API change
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dnl # The generic_fadvise() function is present since 4.19 kernel
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dnl # but it was not exported until Linux 5.3.
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dnl #
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AC_DEFUN([ZFS_AC_KERNEL_SRC_GENERIC_FADVISE], [
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ZFS_LINUX_TEST_SRC([generic_fadvise], [
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#include <linux/fs.h>
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], [
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struct file *fp __attribute__ ((unused)) = NULL;
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loff_t offset __attribute__ ((unused)) = 0;
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loff_t len __attribute__ ((unused)) = 0;
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int advise __attribute__ ((unused)) = 0;
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generic_fadvise(fp, offset, len, advise);
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])
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])
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AC_DEFUN([ZFS_AC_KERNEL_GENERIC_FADVISE], [
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AC_MSG_CHECKING([whether generic_fadvise() is available])
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ZFS_LINUX_TEST_RESULT_SYMBOL([generic_fadvise],
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[generic_fadvise], [mm/fadvise.c], [
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AC_MSG_RESULT(yes)
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AC_DEFINE(HAVE_GENERIC_FADVISE, 1, [yes])
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],[
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AC_MSG_RESULT(no)
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])
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])
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