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Date:   Thu, 24 Aug 2023 15:02:27 +0200
From:   Sabrina Dubroca <sd@queasysnail.net>
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     linux@weissschuh.net, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Robert Marko <robimarko@gmail.com>
Subject: Re: [PATCH net-next] net: generalize calculation of skb extensions
 length
Message-ID: <ZOdU432SDOykeDso@hog>
References: <20230822-skb_ext-simplify-v1-1-9dd047340ab5@weissschuh.net>
 <20230822184644.18966d0f@kernel.org>
 <1e1dde74-edc6-4306-9b1b-0a1b5a658b67@weissschuh.net>
 <20230823075318.4860cebc@kernel.org>
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2023-08-23, 07:53:18 -0700, Jakub Kicinski wrote:
> On Wed, 23 Aug 2023 10:14:48 +0200 (GMT+02:00) linux@weissschuh.net
> wrote:
> > > Could you include more info about the compiler versions you tried
> > > and maybe some objdump? We'll have to take your word for it getting
> > > optimized out, would be great if we had more proof in the commit msg.
> > > --
> > > pw-bot: cr  
> > 
> > Thanks for the feedback.
> > I'll send a v2 with more background soon.
> > 
> > On the other hand this function is only ever
> > executed once, so even if it is slightly inefficient
> > it shouldn't matter.
> 
> Oh you're right, somehow I thought it was for every alloc.
> You can mention it's only run at init in the commit msg if 
> that's easier.

We could also add __init annotations to skb_ext_total_length and
skb_extensions_init to make that clearer.

-- 
Sabrina