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: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1418647641.git.tgraf@suug.ch>
2014-12-15 12:51 ` [PATCH 1/9] rhashtable: Do hashing inside of rhashtable_lookup_compare() Thomas Graf
2014-12-15 12:51 ` [PATCH 5/9] nft_hash: Remove rhashtable_remove_pprev() 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150121052907.GY9719@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=David.Laight@ACULAB.COM \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=herbert@gondor.apana.org.au \
--cc=john.r.fastabend@intel.com \
--cc=josh@joshtriplett.org \
--cc=kaber@trash.net \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=pablo@netfilter.org \
--cc=tgraf@suug.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).