From: Tom Herbert <tom@herbertland.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Willy Tarreau <w@1wt.eu>, Tolga Ceylan <tolga.ceylan@gmail.com>,
Craig Gallek <cgallek@google.com>, Josh Snyder <josh@code406.com>,
Aaron Conole <aconole@bytheb.org>,
"David S. Miller" <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [PATCH 1/1] net: Add SO_REUSEPORT_LISTEN_OFF socket option as drain mode
Date: Thu, 24 Mar 2016 10:26:46 -0700 [thread overview]
Message-ID: <CALx6S36Ej1es8qFi2Q3=199f+rmG=Za02N5ZBWT5DCRqrBEWvQ@mail.gmail.com> (raw)
In-Reply-To: <1458838897.12033.10.camel@edumazet-glaptop3.roam.corp.google.com>
On Thu, Mar 24, 2016 at 10:01 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Thu, 2016-03-24 at 17:50 +0100, Willy Tarreau wrote:
>> On Thu, Mar 24, 2016 at 09:33:11AM -0700, Eric Dumazet wrote:
>> > > --- a/net/ipv4/inet_hashtables.c
>> > > +++ b/net/ipv4/inet_hashtables.c
>> > > @@ -189,6 +189,8 @@ static inline int compute_score(struct sock *sk, struct net *net,
>> > > return -1;
>> > > score += 4;
>> > > }
>> > > + if (sk->sk_reuseport)
>> > > + score++;
>> >
>> > This wont work with BPF
>> >
>> > > if (sk->sk_incoming_cpu == raw_smp_processor_id())
>> > > score++;
>> >
>> > This one does not work either with BPF
>>
>> But this *is* in 4.5. Does this mean that this part doesn't work anymore or
>> just that it's not usable in conjunction with BPF ? In this case I'm less
>> worried, because it would mean that we have a solution for non-BPF aware
>> applications and that BPF-aware applications can simply use BPF.
>>
>
> BPF can implement the CPU choice/pref itself. It has everything needed.
>
>> I don't try to reimplement something already available, but I'm confused
>> by a few points :
>> - the code above already exists and you mention it cannot be used with BPF
>
> _If_ you use BPF, then you can implement a CPU preference using BPF
> instructions. It is a user choice.
>
>> - for the vast majority of applications not using BPF, would the above *still*
>> work (it worked in 4.4-rc at least)
>
>
>> - it seems to me that for BPF to be usable on process shutting down, we'd
>> need to have some form of central knowledge if the goal is to redefine
>> how to distribute the load. In my case there are multiple independant
>> processes forked on startup, so it's unclear to me how each of them could
>> reconfigure BPF when shutting down without risking to break the other ones.
>> - the doc makes me believe that BPF would require privileges to be unset, so
>> that would not be compatible with a process shutting down which has already
>> dropped its privileges after startup, but I could be wrong.
>>
>> Thanks for your help on this,
>> Willy
>>
>
> The point is : BPF is the way to go, because it is expandable.
>
> No more hard points coded forever in the kernel.
>
> Really, when BPF can be the solution, we wont allow adding new stuff in
> the kernel in the old way.
I completely agree with this, but I wonder if we now need a repository
of useful BPF modules. So in the case of implementing functionality
like in SO_REUSEPORT_LISTEN_OFF that might just become a common BPF
program we could direct people to use.
Tom
>
>
>
next prev parent reply other threads:[~2016-03-24 17:26 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-27 0:30 [PATCH 1/1] net: Add SO_REUSEPORT_LISTEN_OFF socket option as drain mode Tolga Ceylan
2015-09-27 1:04 ` Eric Dumazet
2015-09-27 1:37 ` Tolga Ceylan
2015-09-27 1:44 ` Aaron Conole
2015-09-27 2:02 ` Tolga Ceylan
2015-09-27 2:24 ` Eric Dumazet
2015-11-11 5:41 ` Tom Herbert
2015-11-11 6:19 ` Eric Dumazet
2015-11-11 17:05 ` Tom Herbert
2015-11-11 17:23 ` Eric Dumazet
2015-11-11 18:23 ` Tom Herbert
2015-11-11 18:43 ` Eric Dumazet
2015-11-12 1:09 ` Eric Dumazet
2015-12-15 16:14 ` Willy Tarreau
2015-12-15 17:10 ` Eric Dumazet
2015-12-15 17:43 ` Willy Tarreau
2015-12-15 18:21 ` Eric Dumazet
2015-12-15 19:44 ` Willy Tarreau
2015-12-15 21:21 ` Eric Dumazet
2015-12-16 7:38 ` Willy Tarreau
2015-12-16 16:15 ` Willy Tarreau
2015-12-18 16:33 ` Josh Snyder
2015-12-18 18:58 ` Willy Tarreau
2015-12-19 2:38 ` Eric Dumazet
2015-12-19 7:00 ` Willy Tarreau
2015-12-21 20:38 ` Tom Herbert
2015-12-21 20:41 ` Willy Tarreau
2016-03-24 5:10 ` Tolga Ceylan
2016-03-24 6:12 ` Willy Tarreau
2016-03-24 14:13 ` Eric Dumazet
2016-03-24 14:22 ` Willy Tarreau
2016-03-24 14:45 ` Eric Dumazet
2016-03-24 15:30 ` Willy Tarreau
2016-03-24 16:33 ` Eric Dumazet
2016-03-24 16:50 ` Willy Tarreau
2016-03-24 17:01 ` Eric Dumazet
2016-03-24 17:26 ` Tom Herbert [this message]
2016-03-24 17:55 ` Daniel Borkmann
2016-03-24 18:20 ` Tolga Ceylan
2016-03-24 18:24 ` Willy Tarreau
2016-03-24 18:37 ` Eric Dumazet
2016-03-24 22:40 ` Yann Ylavic
2016-03-24 22:49 ` Eric Dumazet
2016-03-24 23:40 ` Yann Ylavic
2016-03-24 23:54 ` Tom Herbert
2016-03-25 0:01 ` Yann Ylavic
2016-03-25 5:28 ` Willy Tarreau
2016-03-25 6:49 ` Eric Dumazet
2016-03-25 8:53 ` Willy Tarreau
2016-03-25 11:21 ` Yann Ylavic
2016-03-25 13:17 ` Eric Dumazet
2016-03-25 0:25 ` David Miller
2016-03-25 0:24 ` David Miller
2016-03-24 18:00 ` Willy Tarreau
2016-03-24 18:21 ` Willy Tarreau
2016-03-24 18:32 ` Eric Dumazet
2016-03-25 15:29 Craig Gallek
2016-03-25 16:21 ` Alexei Starovoitov
2016-03-25 16:31 ` Craig Gallek
2016-03-25 17:00 ` Eric Dumazet
2016-03-25 18:31 ` Willem de Bruijn
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