Linux-WPAN Archive on lore.kernel.org
 help / color / Atom feed
From: ebiederm@xmission.com (Eric W. Biederman)
To: David Laight <David.Laight@ACULAB.COM>
Cc: David Ahern <dsahern@gmail.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	David Miller <davem@davemloft.net>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	"nikita.leshchenko@oracle.com" <nikita.leshchenko@oracle.com>,
	Roopa Prabhu <roopa@cumulusnetworks.com>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Ido Schimmel <idosch@mellanox.com>,
	Jiri Pirko <jiri@mellanox.com>,
	Saeed Mahameed <saeedm@mellanox.com>,
	Alexander Aring <alex.aring@gmail.com>,
	"linux-wpan@vger.kernel.org" <linux-wpan@vger.kernel.org>,
	NetFilter <netfilter-devel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC/RFT net-next 00/17] net: Convert neighbor tables to per-namespace
Date: Fri, 27 Jul 2018 11:27:06 -0500
Message-ID: <87k1pg1w6d.fsf@xmission.com> (raw)
In-Reply-To: <be5c3f5be49e4e22bf1160a1d6d3a1b0@AcuMS.aculab.com> (David Laight's message of "Thu, 26 Jul 2018 11:12:34 +0000")

David Laight <David.Laight@ACULAB.COM> writes:

> From: Eric W. Biederman
>> Sent: 25 July 2018 18:38
> ...
>> >> Further unless I misread something you are increasing the number of
>> >> timers to 3 per namespace.  If I create create a thousand network
>> >> namespaces that feels like it will hurt system performance overall.
>> >
>> > It seems to me the timers are per neighbor entry not table. The per
>> > table ones are for proxies.
>> 
>> It seems I misread that bit when I was refreshing my memory on what
>> everything is doing.  If we can already have 1024 timers that makes
>> timers not a concern.
>
> Surely it is enough to just have a timestamp in each entry.
> Deletion of expired items need not be done until insert (which
> has the table suitable locked) bumps into an expired item.

Part of the state machine the timer is used for is sending retransmits
before we get out first response, so the state machine is not just
about expiry and may not be simple enough to do without a timer.

I honestly don't remember the tradeoffs between the various kinds of
timers.  If we already can have up to 1000 timers without problems I suspect
they are cheap enough optimizing for fewer times simply doesn't matter.
Certainly we are not in regression territory if we don't.

As for bumping into expired items on insert it would be a bad hash table
if we were bumping into any other entries frequently on insert.

Eric

  reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-17 12:06 dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 01/17] net/ipv4: rename ipv4_neigh_lookup to ipv4_dst_neigh_lookup dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 02/17] net/neigh: export neigh_find_table dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 03/17] net/ipv4: wrappers for arp table references dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 04/17] net/ipv4: Remove open coded use of arp table dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 05/17] net/ipv6: wrappers for neighbor table references dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 06/17] net/ipv6: Remove open coded use of neighbor table dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 07/17] drivers/net: remove open coding of neighbor tables dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 08/17] net: Remove nd_tbl from ipv6 stub dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 09/17] net: Remove arp_tbl and nd_tbl from headers dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 10/17] net: Add key_len to neighbor constructor dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 11/17] net: Change neigh_table_init and neigh_table_clear signature dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 12/17] net/neigh: Change neigh_xmit to take an address family dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 13/17] net/neighbor: Convert internal functions away from neigh_tables dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 14/17] net/ipv4: Convert arp table to per namespace dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 15/17] net/ipv6: Convert neighbor table to per-namespace dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 16/17] net/decnet: Move " dsahern
2018-07-17 12:06 ` [PATCH RFC/RFT net-next 17/17] net/neighbor: Remove neigh_tables and NEIGH enum dsahern
2018-07-17 17:40 ` [PATCH RFC/RFT net-next 00/17] net: Convert neighbor tables to per-namespace Cong Wang
2018-07-17 17:43   ` David Ahern
2018-07-17 17:53     ` Cong Wang
2018-07-17 19:02       ` David Ahern
2018-07-17 20:37         ` Cong Wang
2018-07-18  3:59         ` David Miller
2018-07-19 16:16           ` David Ahern
2018-07-19 17:12             ` Cong Wang
2018-07-24 15:14               ` David Ahern
2018-07-24 17:14                 ` David Miller
2018-07-25 18:23                   ` David Ahern
2018-07-24 22:09                 ` Cong Wang
2018-07-25 12:33                   ` Eric W. Biederman
2018-07-25 14:06                     ` David Ahern
2018-07-25 17:38                       ` Eric W. Biederman
2018-07-25 18:13                         ` David Ahern
2018-07-25 19:17                           ` Eric W. Biederman
2018-08-13 21:48                             ` David Ahern
2018-08-15  4:36                               ` Eric W. Biederman
2018-07-26 11:12                         ` David Laight
2018-07-27 16:27                           ` Eric W. Biederman [this message]
2018-07-19  0:54 ` Michael Richardson
2018-07-19 15:49   ` David Ahern
2018-08-12  6:46 ` [RFC/RFT, net-next, " Vasily Averin
2018-08-12 17:37   ` David Ahern

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=87k1pg1w6d.fsf@xmission.com \
    --to=ebiederm@xmission.com \
    --cc=David.Laight@ACULAB.COM \
    --cc=alex.aring@gmail.com \
    --cc=davem@davemloft.net \
    --cc=dsahern@gmail.com \
    --cc=idosch@mellanox.com \
    --cc=jiri@mellanox.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wpan@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    --cc=nikita.leshchenko@oracle.com \
    --cc=roopa@cumulusnetworks.com \
    --cc=saeedm@mellanox.com \
    --cc=stephen@networkplumber.org \
    --cc=xiyou.wangcong@gmail.com \
    /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

Linux-WPAN Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-wpan/0 linux-wpan/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-wpan linux-wpan/ https://lore.kernel.org/linux-wpan \
		linux-wpan@vger.kernel.org
	public-inbox-index linux-wpan

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-wpan


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git