From: Thomas Graf <tgraf@suug.ch>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Miller <davem@davemloft.net>,
josh@joshtriplett.org, alexei.starovoitov@gmail.com,
herbert@gondor.apana.org.au, kaber@trash.net,
ying.xue@windriver.com, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org
Subject: Re: Ottawa and slow hash-table resize
Date: Tue, 24 Feb 2015 08:37:14 +0000 [thread overview]
Message-ID: <20150224083714.GB17306@casper.infradead.org> (raw)
In-Reply-To: <20150223230619.GD15405@linux.vnet.ibm.com>
On 02/23/15 at 03:06pm, Paul E. McKenney wrote:
> On Mon, Feb 23, 2015 at 05:32:52PM -0500, David Miller wrote:
> > I just did a quick scan of all code paths that do inserts into an
> > rhashtable, and it seems like all of them can easily block. So why
> > don't we do that? Make inserts sleep on an rhashtable expansion
> > waitq.
> >
> > There could even be a counter of pending inserts, so the expander can
> > decide to expand further before waking the inserting threads up.
>
> Should be reasonably simple, and certainly seems worth a try!
Agreed. Definitely desirable for nft_hash. I like the pending counter
idea. I'm experimenting with various ideas on blocking inserts for
Netlink. Blocking too long might open DoS vectors as one app could
easily delay the creation of sockets for other applications.
next prev parent reply other threads:[~2015-02-24 8:37 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-23 18:49 Ottawa and slow hash-table resize Paul E. McKenney
2015-02-23 19:12 ` josh
2015-02-23 21:03 ` Thomas Graf
2015-02-23 21:52 ` Paul E. McKenney
2015-02-23 22:32 ` David Miller
2015-02-23 23:06 ` Paul E. McKenney
2015-02-24 8:37 ` Thomas Graf [this message]
2015-02-24 10:39 ` Patrick McHardy
2015-02-24 10:46 ` David Laight
2015-02-24 10:48 ` Patrick McHardy
2015-02-24 17:09 ` David Miller
2015-02-24 17:50 ` Thomas Graf
2015-02-24 18:26 ` David Miller
2015-02-24 18:45 ` josh
2015-02-24 22:34 ` Thomas Graf
2015-02-25 8:56 ` Herbert Xu
2015-02-25 17:38 ` Thomas Graf
2015-02-24 18:33 ` josh
2015-02-25 8:55 ` Herbert Xu
2015-02-25 17:38 ` Thomas Graf
2015-02-23 21:00 ` Thomas Graf
2015-02-23 22:35 ` Paul E. McKenney
2015-02-24 8:59 ` Thomas Graf
2015-02-24 9:38 ` Daniel Borkmann
2015-02-24 10:42 ` Patrick McHardy
2015-02-24 16:14 ` Josh Hunt
2015-02-24 16:25 ` Patrick McHardy
2015-02-24 16:57 ` David Miller
-- strict thread matches above, loose matches on Subject: below --
2015-02-23 22:17 Alexei Starovoitov
2015-02-23 22:34 ` David Miller
2015-02-23 22:37 ` Paul E. McKenney
2015-02-23 23:07 Alexei Starovoitov
2015-02-23 23:15 ` David Miller
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