linux-kernel - RE: [PATCH RESEND net-next 1/2] dpaa2-eth: send a scatter-gather FD instead of realloc-ing

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Message-ID: <c4e033fe17674685b64a60055c68704e@AcuMS.aculab.com>
Date:   Fri, 11 Dec 2020 09:30:43 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Daniel Thompson' <daniel.thompson@...aro.org>,
        Ioana Ciornei <ioana.ciornei@....com>
CC:     "linux-netdev@...r.kernel.org" <linux-netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH RESEND net-next 1/2] dpaa2-eth: send a scatter-gather FD
 instead of realloc-ing

From: Daniel Thompson
> Sent: 10 December 2020 17:32
> 
> On Mon, Jun 29, 2020 at 06:47:11PM +0000, Ioana Ciornei wrote:
> > Instead of realloc-ing the skb on the Tx path when the provided headroom
> > is smaller than the HW requirements, create a Scatter/Gather frame
> > descriptor with only one entry.

Is it worth simplifying the code by permanently allocating (and dma-mapping)
the extra structure for every ring entry.
It is (probably) only one page and 1 iommu entry.

	David

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