From: Thomas Graf <tgraf@suug.ch>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <eric.dumazet@gmail.com>,
Patrick McHardy <kaber@trash.net>,
Josh Triplett <josh@joshtriplett.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
netdev@vger.kernel.org
Subject: Re: [v2 PATCH 7/10] rhashtable: Disable automatic shrinking
Date: Mon, 23 Mar 2015 09:36:32 +0000 [thread overview]
Message-ID: <20150323093632.GD16023@casper.infradead.org> (raw)
In-Reply-To: <20150323092806.GA12506@gondor.apana.org.au>
On 03/23/15 at 08:28pm, Herbert Xu wrote:
> On Mon, Mar 23, 2015 at 08:33:19AM +0000, Thomas Graf wrote:
> >
> > 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?
next prev parent reply other threads:[~2015-03-23 9:36 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-22 8:03 [v2 PATCH 0/10] rhashtable: Multiple rehashing Herbert Xu
2015-03-22 8:03 ` [v2 PATCH 1/10] rhashtable: Add barrier to ensure we see new tables in walker Herbert Xu
2015-03-22 10:47 ` Thomas Graf
2015-03-22 8:04 ` [v2 PATCH 2/10] rhashtable: Eliminate unnecessary branch in rht_key_hashfn Herbert Xu
2015-03-22 11:07 ` Thomas Graf
2015-03-22 8:04 ` [v2 PATCH 3/10] rhashtable: Allow hashfn to be unset Herbert Xu
2015-03-22 11:55 ` Thomas Graf
2015-03-22 12:04 ` Herbert Xu
2015-03-22 12:32 ` Thomas Graf
2015-03-22 21:12 ` Herbert Xu
2015-03-23 9:58 ` Thomas Graf
2015-03-23 10:18 ` Herbert Xu
2015-03-23 14:29 ` David Laight
2015-03-22 8:04 ` [v2 PATCH 4/10] netlink: Use default rhashtable hashfn Herbert Xu
2015-03-22 11:55 ` Thomas Graf
2015-03-23 1:18 ` Simon Horman
2015-03-23 12:56 ` Herbert Xu
2015-03-22 8:04 ` [v2 PATCH 5/10] tipc: " Herbert Xu
2015-03-22 11:56 ` Thomas Graf
2015-03-22 8:04 ` [v2 PATCH 6/10] netfilter: " Herbert Xu
2015-03-22 11:56 ` Thomas Graf
2015-03-23 11:32 ` Herbert Xu
2015-03-22 8:04 ` [v2 PATCH 7/10] rhashtable: Disable automatic shrinking Herbert Xu
2015-03-22 12:17 ` Thomas Graf
2015-03-22 13:06 ` Thomas Graf
2015-03-23 0:07 ` Herbert Xu
2015-03-23 8:37 ` Thomas Graf
2015-03-23 9:29 ` Herbert Xu
2015-03-23 9:43 ` Thomas Graf
2015-03-23 0:09 ` Herbert Xu
2015-03-23 8:33 ` Thomas Graf
2015-03-23 9:28 ` Herbert Xu
2015-03-23 9:36 ` Thomas Graf [this message]
2015-03-23 9:39 ` Herbert Xu
2015-03-23 9:44 ` Herbert Xu
2015-03-23 10:08 ` Thomas Graf
2015-03-23 10:19 ` Herbert Xu
2015-03-23 16:45 ` David Miller
2015-03-23 16:44 ` David Miller
2015-03-23 21:48 ` Herbert Xu
2015-03-23 22:13 ` Thomas Graf
2015-03-22 8:04 ` [v2 PATCH 8/10] rhashtable: Add multiple rehash support Herbert Xu
2015-03-22 8:04 ` [v2 PATCH 9/10] rhashtable: Allow GFP_ATOMIC bucket table allocation Herbert Xu
2015-03-22 8:04 ` [v2 PATCH 10/10] rhashtable: Add immediate rehash during insertion Herbert Xu
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