Re: [PATCH] adding per sb inode list to make invalidate_inodes() faster

[Andrew Morton <akpm@osdl.org>]

William Lee Irwin III <wli@holomorphy.com> wrote:
>
> On Thu, Sep 09, 2004 at 11:06:22AM -0700, Andrew Morton wrote:
>  > Yes.
>  > I have not merged it up because it seems rather dopey to add eight bytes to
>  > the inode to speed up something as rare as umount.
>  > Is there a convincing reason for proceeding with the change?
> 
>  The only motive I'm aware of is for latency in the presence of things
>  such as autofs. It's also worth noting that in the presence of things
>  such as removable media umount is also much more common. I personally
>  find this sufficiently compelling. Kirill may have additional ammunition.

Well.  That's why I'm keeping the patch alive-but-unmerged.  Waiting to see
who wants it.

There are people who have large machines which are automounting hundreds of
different NFS servers.  I'd certainly expect such a machine to experience
ongoing umount glitches.  But no reports have yet been sighted by this
little black duck.

>  Also, the additional sizeof(struct list_head) is only a requirement
>  while the global inode LRU is maintained. I believed it would have
>  been beneficial to have localized the LRU to the sb also, which would
>  have maintained sizeof(struct inode0 at parity with current mainline.

Could be.  We would give each superblock its own shrinker callback and
everything should balance out nicely (hah).