Re: 21 million inodes is causing severe pauses.

[Andrew Morton <akpm@osdl.org>]

Robin Holt <holt@sgi.com> wrote:
>
> One significant problem we are running into is autofs trying to umount the
> file systems.  This results in the umount grabbing the BKL and inode_lock,
> holding it while it scans through the inode_list and others looking for
> inodes used by this super block and attempting to free them.

You'll need invalidate_inodes-speedup.patch and
break-latency-in-invalidate_list.patch (or an equivalent).

That'll get you most of the way, but the BKL will still be a problem.

Removing lock_kernel() in the umount path is probably a major project so
for now, you can just drop and reacquire it by doing
release_kernel_lock()/reacquire_kernel_lock() around invalidate_inodes().

(You'll need to use that pair rather than unlock_kernel/lock_kernel because
it seems that invalidate_inodes can be called under various depths of
lock_kernel()).