From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
Patrick McHardy <kaber@trash.net>, Thomas Graf <tgraf@suug.ch>,
David Laight <David.Laight@ACULAB.COM>,
"davem@davemloft.net" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"edumazet@google.com" <edumazet@google.com>,
"john.r.fastabend@intel.com" <john.r.fastabend@intel.com>,
"josh@joshtriplett.org" <josh@joshtriplett.org>,
"netfilter-devel@vger.kernel.org"
<netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking
Date: Tue, 20 Jan 2015 21:29:07 -0800 [thread overview]
Message-ID: <20150121052907.GY9719@linux.vnet.ibm.com> (raw)
In-Reply-To: <20150121052333.GA23382@gondor.apana.org.au>
On Wed, Jan 21, 2015 at 04:23:33PM +1100, Herbert Xu wrote:
> On Mon, Jan 19, 2015 at 01:01:21AM -0800, Paul E. McKenney wrote:
> >
> > One unconventional way of handling this is to associate the scan with
> > a one-to-one resize operation. This can be implemented to have the
> > effect of taking a snapshot of the table.
>
> The problem is that in general (not for netfilter, but certainly
> other rhashtable users such as netlink) dumps/walks can be started
> by ordinary users and I don't think we can afford creating a
> snapshot for each one, or can we?
Well, you -could- batch them up, so that a single snapshot covered
several users, and once that set was done and memory reclaimed, a second
snapshot could cover any additional users that requested dumps/walks in
the meantime. Or are users allowed to walk arbitrarily slowly through
the table?
Thanx, Paul
next prev parent reply other threads:[~2015-01-21 5:29 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-15 12:51 [PATCH 0/9] rhashtable: Per bucket locks & deferred table resizing Thomas Graf
2014-12-15 12:51 ` [PATCH 1/9] rhashtable: Do hashing inside of rhashtable_lookup_compare() Thomas Graf
2014-12-15 12:51 ` [PATCH 2/9] rhashtable: Use rht_obj() instead of manual offset calculation Thomas Graf
2014-12-15 12:51 ` [PATCH 3/9] rhashtable: Convert bucket iterators to take table and index Thomas Graf
2014-12-15 12:51 ` [PATCH 4/9] rhashtable: Factor out bucket_tail() function Thomas Graf
2014-12-15 12:51 ` [PATCH 5/9] nft_hash: Remove rhashtable_remove_pprev() Thomas Graf
2014-12-15 12:51 ` [PATCH 6/9] spinlock: Add spin_lock_bh_nested() Thomas Graf
2014-12-15 12:51 ` [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking Thomas Graf
2015-01-16 15:34 ` Patrick McHardy
2015-01-16 15:58 ` Thomas Graf
2015-01-16 16:03 ` Patrick McHardy
2015-01-16 16:15 ` Thomas Graf
2015-01-16 16:32 ` Patrick McHardy
2015-01-16 16:38 ` Thomas Graf
2015-01-16 16:51 ` Patrick McHardy
2015-01-16 16:43 ` David Laight
2015-01-16 16:53 ` Thomas Graf
2015-01-16 18:36 ` Patrick McHardy
2015-01-16 19:18 ` Thomas Graf
2015-01-16 19:35 ` Patrick McHardy
2015-01-16 20:46 ` Pablo Neira Ayuso
2015-01-16 20:53 ` Patrick McHardy
2015-01-19 9:01 ` Paul E. McKenney
2015-01-21 5:23 ` Herbert Xu
2015-01-21 5:29 ` Paul E. McKenney [this message]
2015-01-21 5:30 ` Herbert Xu
2015-01-21 5:36 ` Paul E. McKenney
2015-01-16 20:49 ` Herbert Xu
2015-01-16 21:31 ` Patrick McHardy
2015-01-17 0:33 ` Herbert Xu
2015-01-17 8:06 ` Patrick McHardy
2015-01-17 9:32 ` Herbert Xu
2015-01-17 9:51 ` Patrick McHardy
2015-01-17 10:13 ` Herbert Xu
2015-01-17 11:56 ` Patrick McHardy
2015-01-16 21:36 ` Thomas Graf
2015-01-16 22:07 ` Patrick McHardy
2015-01-16 23:34 ` Thomas Graf
2015-01-17 8:02 ` Patrick McHardy
2015-01-19 12:58 ` Thomas Graf
2015-01-19 9:45 ` David Laight
2014-12-15 12:51 ` [PATCH 8/9] rhashtable: Supports for nulls marker Thomas Graf
2014-12-15 12:51 ` [PATCH 9/9] netlink: Lockless lookup with RCU grace period in socket release Thomas Graf
2014-12-15 13:00 ` [PATCH 0/9 net-next] rhashtable: Per bucket locks & deferred table resizing Thomas Graf
2014-12-15 16:18 ` David Miller
2014-12-15 16:27 ` Thomas Graf
-- strict thread matches above, loose matches on Subject: below --
2015-01-02 22:00 [PATCH 0/9 net-next v2] " Thomas Graf
2015-01-02 22:00 ` [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking Thomas Graf
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