From: Andrew Gallatin <gallatin@myri•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Jon Mason <mason@myri•com>, David Miller <davem@davemloft•net>,
netdev <netdev@vger•kernel.org>
Subject: Re: [PATCH net-next] myri10ge: fix truesize underestimation
Date: Thu, 20 Oct 2011 17:04:11 -0400 [thread overview]
Message-ID: <4EA08CCB.8030207@myri.com> (raw)
In-Reply-To: <1319144356.2854.36.camel@edumazet-laptop>
On 10/20/11 16:59, Eric Dumazet wrote:
> Le jeudi 20 octobre 2011 à 16:45 -0400, Andrew Gallatin a écrit :
>> On 10/20/11 16:44, Eric Dumazet wrote:
>>> Le jeudi 20 octobre 2011 à 15:33 -0500, Jon Mason a écrit :
>>>> On Thu, Oct 20, 2011 at 3:10 PM, Eric Dumazet<eric.dumazet@gmail•com> wrote:
>>>>> skb->truesize must account for allocated memory, not the used part of
>>>>> it. Doing this work is important to avoid unexpected OOM situations.
>>>>>
>>>>> Signed-off-by: Eric Dumazet<eric.dumazet@gmail•com>
>>>>
>>>> Acked-by: Jon Mason<mason@myri•com>
>>>
>>> Thanks for reviewing Jon !
>>>
>>>
>>
>> Please wait a second.. I think the patch is incorrect.
>>
>> There is already code in myri10ge_rx_skb_build() which
>> attempts to set the truesize. However, it sets it to
>> the used, rather than the allocated size so it is apparently
>> incorrect.
>>
>> I'd prefer we fix that code.
>
> Well, I believe I did exactly that :)
>
> truesize of initial skb is fine.
>
> Then for everay frag added, you must add to skb-truesize the allocated
> memory for this frag.
>
> You add frags of a given size (small or big)
>
> In the end, its truesize += bytes * number_of_frags
>
> (bytes being small_size or big_size)
>
>
OK, I'm feeling foolish. I somehow missed the first hunk
of your patch (some local change made it not apply cleanly, and
I did not notice that).
Yes, your patch is correct. Sorry for the hassle!
Acked-by: Andrew Gallatin <gallatin@myri•com>
next prev parent reply other threads:[~2011-10-20 21:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-20 20:10 [PATCH net-next] myri10ge: fix truesize underestimation Eric Dumazet
2011-10-20 20:33 ` Jon Mason
2011-10-20 20:44 ` Eric Dumazet
2011-10-20 20:45 ` Andrew Gallatin
2011-10-20 20:59 ` Eric Dumazet
2011-10-20 21:03 ` David Miller
2011-10-20 21:04 ` Andrew Gallatin [this message]
2011-10-20 21:06 ` Eric Dumazet
2011-10-20 21:42 ` David Miller
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