Pasted

~# grep -w -e / -e /mnt/host /proc/mounts 
/dev/root / ext4 rw,noatime 0 0
home /mnt/host 9p rw,sync,dirsync,noatime,access=client,trans=virtio 0 0
 ~# time tar xf linux-5.5.6.tar.xz
 real    0m13.629s
user    0m9.417s
sys     0m5.015s
 ~# cd /mnt/host/
/mnt/host# time tar xf ~/linux-5.5.6.tar.xz
 real    2m59.245s
user    0m11.426s
sys     0m17.354s
 ~# cd
root@debian64:~# time rm -rf linux-5.5.6/
 real    0m0.732s
user    0m0.060s
sys     0m0.658s
 ~# cd /mnt/host/
root@debian64:/mnt/host# time rm -rf linux-5.5.6/
 real    0m38.672s
user    0m0.212s
sys     0m3.172s