Hi util-linux@xxxxxxxxxxxxxxx
I have 1 question which need confirm.
in the RHEL7.0alpha version
nfs-utils-1.2.5-3.el7.x86_64 --> use mount_libmount.c
util-linux-2.20.1-2.el7.x86_64
when umount a NFS directory, the mnt_table_parse_mtab() function will merge user options(/run/mount/utab)
into mountinfo(/proc/self/mountinfo)from kernel. if the mount number is large, leading to umount a directory
time-consuming. the complexity of the algorithm is O(n(n+1)/2).
but in the old version(RHEL6.3GA/nfs-utils-1.2.3-26.el6.x86_64(use mount.c)), only according to the parameters of umount command,
find the corresponding record in the /etc/mtab file
Question)*:* merg the tow file are necessary for umount a dir?
TEST LOG:
#cat mount_test.sh
#!/bin/bash
mount=/tmp/mount
if [ ! -d $mount ]; then
mkdir -p $mount
fi
for dir in {1..8000}; do
if [ ! -d $mount/$dir ]; then
mkdir -p $mount/$dir
fi
echo mount $dir
mount -t nfs 127.0.0.1:/ $mount/$dir
done
# time umount /tmp/mount/1 --------->RHEL7.0alpha
real 0m2.395s
user 0m1.640s
sys 0m0.466s
# time umount /tmp/mount/1 --------->RHEL6.3GA
real 0m0.159s
user 0m0.042s
sys 0m0.114s
thanks.
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