From: Eric Dumazet <eric.dumazet@gmail.com>
To: Tony Lindgren <tony@atomide.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-omap@vger.kernel.org
Subject: Re: [PATCH] net: Add back alignment for size for __alloc_skb
Date: Thu, 03 Nov 2011 00:20:59 +0100 [thread overview]
Message-ID: <4EB1D05B.6020605@gmail.com> (raw)
In-Reply-To: <20111102231917.GN31337@atomide.com>
On 03/11/2011 00:19, Tony Lindgren wrote:
> * David Miller <davem@davemloft.net> [111102 15:42]:
>> c>
>>> The issue is calculation of skb->end, which is based upon calculated
>>> 'size' variable.
>>>
>>> skb->end determines alignment of skb_shared_info, which is where the
>>> alignment problem is occuring for Tony.
>>
>> Right, and SMP_CACHE_BYTES setting should save us in any case.
>>
>> For ARM, SMP_CACHE_BYTES seems to be set to L1_CACHE_BYTES which in
>> turn is set via ARM_L1_CACHE_SHIFT which can be set seemingly to any
>> value but the defaults are 5 and 6 which should be OK.
>>
>> So unless Tony is using a non-standard setting of ARM_L1_CACHE_SHIFT,
>> this report is a bit mysterious.
>
> This is happening at least with omap1_defconfig. In that case we have
> ARM_L1_CACHE_SHIFT=5.
>
> Regards,
>
> Tony
Do you use SLOB, SLUB or SLAB ?
Thanks
next prev parent reply other threads:[~2011-11-02 23:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-02 22:43 [PATCH] net: Add back alignment for size for __alloc_skb Tony Lindgren
2011-11-02 22:55 ` Eric Dumazet
2011-11-02 23:09 ` David Miller
2011-11-02 23:13 ` David Miller
2011-11-02 23:14 ` Eric Dumazet
2011-11-02 23:17 ` David Miller
2011-11-02 23:19 ` Tony Lindgren
2011-11-02 23:20 ` Eric Dumazet [this message]
2011-11-02 23:24 ` Tony Lindgren
2011-11-02 23:31 ` Eric Dumazet
2011-11-02 23:40 ` Tony Lindgren
2011-11-03 22:09 ` David Miller
2011-11-02 23:22 ` David Miller
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