From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: nanditad@google.com, netdev@vger.kernel.org, ycheng@google.com,
codel@lists.bufferbloat.net, mattmathis@google.com,
ncardwell@google.com
Subject: Re: [RFC PATCH] tcp: limit data skbs in qdisc layer
Date: Mon, 09 Jul 2012 16:55:22 +0200 [thread overview]
Message-ID: <1341845722.3265.3065.camel@edumazet-glaptop> (raw)
In-Reply-To: <20120709.000834.1182150057463599677.davem@davemloft.net>
On Mon, 2012-07-09 at 00:08 -0700, David Miller wrote:
> I'm suspicious and anticipate that 10G will need more queueing than
> you are able to get away with tg3 at 1G speeds. But it is an exciting
> idea nonetheless :-)
There is a fundamental problem calling any xmit function from skb
destructor.
skb destructor can be called while qdisc lock is taken, so we can
deadlock trying to reacquire it.
One such path is the dev_deactivate_queue() -> qdisc_reset() ->
qdisc_reset_queue(), but also any dropped skbs in qdisc.
So I should only do this stuff from a separate context, for example a
tasklet or timer.
Alternative would be to use dev_kfree_skb_irq() for all dropped skbs in
qdisc layer.
next prev parent reply other threads:[~2012-07-09 14:55 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-28 17:07 [PATCH net-next] fq_codel: report congestion notification at enqueue time Eric Dumazet
2012-06-28 17:51 ` Dave Taht
2012-06-28 18:12 ` Eric Dumazet
2012-06-28 22:56 ` Yuchung Cheng
2012-06-28 23:47 ` Dave Taht
2012-06-29 4:50 ` Eric Dumazet
2012-06-29 5:24 ` Dave Taht
2012-07-04 10:11 ` [RFC PATCH] tcp: limit data skbs in qdisc layer Eric Dumazet
2012-07-09 7:08 ` David Miller
2012-07-09 8:03 ` Eric Dumazet
2012-07-09 8:48 ` Eric Dumazet
2012-07-09 14:55 ` Eric Dumazet [this message]
2012-07-10 13:28 ` Lin Ming
2012-07-10 15:13 ` [RFC PATCH v2] tcp: TCP Small Queues Eric Dumazet
2012-07-10 17:06 ` Eric Dumazet
2012-07-10 17:37 ` Yuchung Cheng
2012-07-10 18:32 ` Eric Dumazet
2012-07-11 15:11 ` Eric Dumazet
2012-07-11 15:16 ` Ben Greear
2012-07-11 15:25 ` Eric Dumazet
2012-07-11 15:43 ` Ben Greear
2012-07-11 15:54 ` Eric Dumazet
2012-07-11 16:03 ` Ben Greear
2012-07-11 18:23 ` Rick Jones
2012-07-11 23:38 ` Eric Dumazet
2012-07-11 18:44 ` Rick Jones
2012-07-11 23:49 ` Eric Dumazet
2012-07-12 7:34 ` Eric Dumazet
2012-07-12 7:37 ` David Miller
2012-07-12 7:51 ` Eric Dumazet
2012-07-12 14:55 ` Tom Herbert
2012-07-12 13:33 ` John Heffner
2012-07-12 13:46 ` Eric Dumazet
2012-07-12 16:44 ` John Heffner
2012-07-12 16:54 ` Jim Gettys
2012-06-28 23:52 ` [PATCH net-next] fq_codel: report congestion notification at enqueue time Nandita Dukkipati
2012-06-29 4:18 ` Eric Dumazet
2012-06-29 4:53 ` Eric Dumazet
2012-06-29 5:12 ` David Miller
2012-06-29 5:24 ` Eric Dumazet
2012-06-29 5:29 ` David Miller
2012-06-29 5:50 ` Eric Dumazet
2012-06-29 7:53 ` David Miller
2012-06-29 8:04 ` David Miller
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