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From: Larry Finger <Larry.Finger@lwfinger.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Neal Cardwell <ncardwell@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	John W Linville <linville@tuxdriver.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Regression associated with commit c8628155ece3 - "tcp: reduce out_of_order memory use"
Date: Thu, 23 Aug 2012 15:57:09 -0500	[thread overview]
Message-ID: <50369925.3050705@lwfinger.net> (raw)
In-Reply-To: <1345694593.5904.87.camel@edumazet-glaptop>

On 08/22/2012 11:03 PM, Eric Dumazet wrote:
>
> Changing the allocation size removes the problem ? thats really strange.
>
> If you try different sizes in the 9100-30720 range, can you pinpoint the
> failure threshold ?

The allocation size change did not fix the problem. It turned out that 10 tries 
from a secure web page were not enough to trigger this intermittent problem that 
particular test.

Based on DaveM's comment that skb->truesize could be wrong, I tried setting 
truesize after every netdev_alloc_skb() call. Of course, that had no effect. I 
then found https://lkml.org/lkml/2010/11/19/505I, which clearly states why this 
need not be done.

What skb modifications require that truesize be adjusted? The driver never 
resets skb->len or skb->data_len for any buffers, other than setting skb->len to 
zero.

Thanks,

Larry


  reply	other threads:[~2012-08-23 20:57 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22  4:07 Regression associated with commit c8628155ece3 - "tcp: reduce out_of_order memory use" Larry Finger
2012-08-22  4:26 ` David Miller
2012-08-22  5:15 ` Eric Dumazet
2012-08-22 16:00   ` Larry Finger
2012-08-22 21:33   ` Larry Finger
2012-08-23  4:03     ` Eric Dumazet
2012-08-23 20:57       ` Larry Finger [this message]
2012-08-23 21:26         ` Eric Dumazet
2012-08-24 14:09           ` Larry Finger
2012-08-24 14:55             ` Eric Dumazet
2012-08-24 15:49               ` Larry Finger
2012-08-24 16:01                 ` Eric Dumazet
2012-08-24 16:29                   ` Larry Finger
2012-08-24 15:19             ` David Miller
2012-08-24 15:58               ` Larry Finger
2012-08-24 16:18                 ` Eric Dumazet
2012-08-24 16:23                   ` Eric Dumazet
2012-08-24 16:58                     ` Larry Finger
2012-08-24 17:47                       ` Eric Dumazet
2012-08-27 17:55                         ` Larry Finger
2012-08-27 18:21                           ` Eric Dumazet
2012-08-27 20:39                             ` Larry Finger
2012-09-10  8:39                           ` Eric Dumazet
2012-09-10  8:39                             ` Eric Dumazet
2012-09-10 14:53                             ` Larry Finger
2012-09-10 15:04                               ` Eric Dumazet
2012-09-10 15:04                                 ` Eric Dumazet
2012-09-10 17:55                                 ` [PATCH] staging: r8712u: fix bug in r8712_recv_indicatepkt() Eric Dumazet
2012-09-10 18:34                                   ` Larry Finger
2012-09-10 18:34                                     ` Larry Finger

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