netdev - Re: [PATCH v2 net-next 0/3] net: Add incoming CPU mask to sockets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Tue, 26 May 2015 15:42:33 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Tom Herbert <tom@...bertland.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 net-next 0/3] net: Add incoming CPU mask to sockets

On Tue, 2015-05-26 at 13:01 -0700, Tom Herbert wrote:

> In that case there's no guarantee that any two packets in a flow will
> hit the same CPU so there's no way to establish affinity to the
> interrupt anyway. RFS would work okay to get affinity of the soft
> processing, but there would be no point in trying to do any affinity
> with incoming cpu so this feature wouldn't help.

This is why I think this patch can hurt users.

RPS/RFS/smp_affinity/SO_REUSEPORT/cpuhotplug are only hints, that would
never break TCP session establishment, even with hash collisions and
sockets being added/deleted to SO_REUSEPORT pools.

It works in _all_ situations. Even the crazy/stupid setups.

Your patch is breaking this rule, without any clear documentation on how
to make sure everything is properly setup.

I am not sure my tcp listener stuff will be finished for 4.2, because I
had to spend lot of time to more urgent stuff lately, like reviewing
patches ;)

I would prefer your patch is added for 4.3, not before.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html