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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
	hans.schillstrom@ericsson.com, subramanian.vijay@gmail.com,
	dave.taht@gmail.com, netdev@vger.kernel.org,
	ncardwell@google.com, therbert@google.com, mph@hoth.dk
Subject: Re: [PATCH v2 net-next] tcp: avoid tx starvation by SYNACK packets
Date: Wed, 27 Jun 2012 11:23:34 +0200	[thread overview]
Message-ID: <1340789014.2028.165.camel@localhost> (raw)
In-Reply-To: <1340786710.26242.37.camel@edumazet-glaptop>

On Wed, 2012-06-27 at 10:45 +0200, Eric Dumazet wrote:
> On Wed, 2012-06-27 at 10:21 +0200, Jesper Dangaard Brouer wrote:
> 
> > It works because we have a spinlock problem in the code... Perhaps, they
> > did it, because we have have locking/contention problem, not the other
> > way around ;-)  How about fixing the code instead? ;-)))
> 
> The socket lock is currently mandatory.
>
> It's really _hard_ to remove it, your attempts added a lot of races.

Yes, its really hard to remove completely.  That's why I choose _only_
to handle the SYN cookie "overload" case, and leave the rest locked, and
I also introduced extra locking in the latest patches.  I know it was
not perfect, hence the RFC tag, but I hope I didn't add that many races.


> I want to do it properly, adding needed RCU and array of spinlocks were
> appropriate.

I really appreciate that you will attempt to fix this properly.  Like a
real network ninja ;-).

  reply	other threads:[~2012-06-27  9:23 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-31 21:56 [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Eric Dumazet
2012-05-31 23:03 ` David Miller
2012-06-01  4:48   ` Eric Dumazet
2012-06-01 17:46     ` David Miller
2012-06-01  7:00 ` [PATCH] tcp: do not create inetpeer on SYNACK message Eric Dumazet
2012-06-01 18:24   ` David Miller
2012-06-01 21:34   ` Hans Schillström
2012-06-02  6:56     ` Eric Dumazet
2012-06-01  7:36 ` [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Hans Schillstrom
2012-06-01  9:34   ` Eric Dumazet
2012-06-02  1:28 ` Dave Taht
2012-06-02  5:46   ` Eric Dumazet
2012-06-23  7:34     ` Vijay Subramanian
2012-06-23  8:42       ` [PATCH v2 " Eric Dumazet
2012-06-25  6:24         ` Hans Schillstrom
2012-06-25 22:43         ` David Miller
2012-06-26  4:51           ` Eric Dumazet
2012-06-26  4:55             ` David Miller
2012-06-26  5:34               ` Hans Schillstrom
2012-06-26  7:11                 ` David Miller
2012-06-26  7:27                   ` Hans Schillstrom
2012-06-26 17:02                 ` Eric Dumazet
2012-06-27  5:23                   ` Hans Schillstrom
2012-06-27  8:22                     ` David Miller
2012-06-27  8:25                       ` Jesper Dangaard Brouer
2012-06-27  8:30                       ` Hans Schillstrom
2012-06-27  8:40                       ` Eric Dumazet
2012-06-27  8:48                         ` David Miller
2012-06-27  6:32                   ` Jesper Dangaard Brouer
2012-06-27  6:54                     ` David Miller
2012-06-27  7:24                       ` Jesper Dangaard Brouer
2012-06-27  7:30                         ` Eric Dumazet
2012-06-27  7:54                           ` Jesper Dangaard Brouer
2012-06-27  8:02                             ` Eric Dumazet
2012-06-27  8:21                               ` Jesper Dangaard Brouer
2012-06-27  8:45                                 ` Eric Dumazet
2012-06-27  9:23                                   ` Jesper Dangaard Brouer [this message]
2012-06-27  8:13                           ` David Miller
2012-06-27 19:50                       ` Florian Westphal
2012-06-27 21:39                         ` Eric Dumazet
2012-06-27 22:23                           ` David Miller
2012-06-27 22:23                         ` David Miller

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