Hi all, Attached is v2 of the umount optimization. Please take a look at v1 for the original introduction to the problem. Al made it clear in the previous RFC that if a filesystem is shut down by umount(2), that the shut down needs to be completed before the return from the syscall. The change in this version looks to address that by only deferring the release on lazy umounts. Lucas v2: - Only defer releasing umount'ed filesystems for lazy umounts v1: https://lore.kernel.org/all/20230119205521.497401-1-echanude@xxxxxxxxxx/ Lucas Karpinski (1): fs/namespace: defer RCU sync for MNT_DETACH umount fs/namespace.c | 51 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 45 insertions(+), 6 deletions(-) -- 2.44.0