Re: [v2 PATCH 7/10] rhashtable: Disable automatic shrinking

On 03/23/15 at 08:28pm, Herbert Xu wrote:

On Mon, Mar 23, 2015 at 08:33:19AM +0000, Thomas Graf wrote:

quoted

I'm not claiming you always want shrinking but what gain is there by
removing integrated support? Can you show numbers that the additional
branch actually hurts?

You never want automatic shrinking unless all your users are
trusted.  I doubt there would be many rhashtable users where
this would apply.  Even nft_hash is quite tenuous.

Why?

Besdies, if you really want automatic shrinking, you could always
do it in the caller of rhashtable_remove.  That way only you
would pay for the cost and not everybody else.

Same can be said for growing. Why do we differ between the two?
Would you expect users requiring shrinking() to call
rhashtable_shrink() after every remove? Should they encode their
own logic based on rhashtable internals?