From: David Miller <davem@davemloft.net>
To: jeffrey.t.kirsher@intel.com
Cc: dnelson@redhat.com, netdev@vger.kernel.org, andy@greyhouse.net
Subject: Re: [PATCH net-next-2.6] e1000: save skb counts in TX to avoid cache misses
Date: Fri, 26 Aug 2011 12:55:29 -0400 (EDT) [thread overview]
Message-ID: <20110826.125529.1284864994760116940.davem@davemloft.net> (raw)
In-Reply-To: <1314330760.2097.39.camel@jtkirshe-mobl>
From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Date: Thu, 25 Aug 2011 20:52:39 -0700
> On Thu, 2011-08-25 at 17:39 -0700, Dean Nelson wrote:
>> Virtual Machines with emulated e1000 network adapter running on
>> Parallels'
>> server were seeing kernel panics due to the e1000 driver dereferencing
>> an
>> unexpected NULL pointer retrieved from buffer_info->skb.
>>
>> The problem has been addressed for the e1000e driver, but not for the
>> e1000.
>> Since the two drivers share similar code in the affected area, a port
>> of the
>> following e1000e driver commit solves the issue for the e1000 driver:
>>
>> commit 9ed318d546a29d7a591dbe648fd1a2efe3be1180
>> Author: Tom Herbert <therbert@google.com>
>> Date: Wed May 5 14:02:27 2010 +0000
>>
>> e1000e: save skb counts in TX to avoid cache misses
>>
>> In e1000_tx_map, precompute number of segements and bytecounts
>> which
>> are derived from fields in skb; these are stored in buffer_info.
>> When
>> cleaning tx in e1000_clean_tx_irq use the values in the associated
>> buffer_info for statistics counting, this eliminates cache misses
>> on skb fields.
>>
>>
>> Signed-off-by: Dean Nelson <dnelson@redhat.com>
>
> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Applied, thanks.
prev parent reply other threads:[~2011-08-26 16:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-26 0:39 [PATCH net-next-2.6] e1000: save skb counts in TX to avoid cache misses Dean Nelson
2011-08-26 3:52 ` Jeff Kirsher
2011-08-26 16:55 ` David Miller [this message]
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