From: Eric Dumazet <eric.dumazet@gmail.com>
To: Andrew Gallatin <gallatin@myri.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 22:59:16 +0200 [thread overview]
Message-ID: <1319144356.2854.36.camel@edumazet-laptop> (raw)
In-Reply-To: <4EA0885A.9010009@myri.com>
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)
next prev parent reply other threads:[~2011-10-20 20:59 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 [this message]
2011-10-20 21:03 ` David Miller
2011-10-20 21:04 ` Andrew Gallatin
2011-10-20 21:06 ` Eric Dumazet
2011-10-20 21:42 ` David Miller
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