From: Oliver Neukum <oneukum@suse.com>
To: "David Laight" <David.Laight@ACULAB.COM>, "'Bjørn Mork'" <bjorn@mork.no>
Cc: "'Jim Baxter'" <jim_baxter@mentor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [RFC V1 1/1] net: cdc_ncm: Reduce memory use when kernel memory low
Date: Mon, 22 May 2017 15:27:17 +0200 [thread overview]
Message-ID: <1495459637.11462.19.camel@suse.com> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DCFFFAC2B@AcuExch.aculab.com>
Am Freitag, den 19.05.2017, 14:46 +0000 schrieb David Laight:
> For XHCI it isn't too bad because it will do arbitrary scatter-gather
> (apart from the ring end).
> But I believe the earlier controllers only support fragments that
> end on usb packet boundaries.
>
> I looked at the usbnet code a few years ago, I'm sure it ought to
> be possible to shortcut most of the code that uses URB and directly
> write to the xhci (in particular) ring descriptors.
Hi,
we cannot break the layering. URBs can support scatter/gather and
that infrastructure must be used. And usbnet will work with sg used
in skbs. What you should honor in general is not splitting packets.
So 512 byte chunks.
Regards
Oliver
prev parent reply other threads:[~2017-05-22 13:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 17:41 [RFC V1 0/1] Reduce cdc_ncm memory use when kernel memory low Jim Baxter
2017-05-16 17:41 ` [RFC V1 1/1] net: cdc_ncm: Reduce " Jim Baxter
2017-05-16 18:24 ` Bjørn Mork
2017-05-17 7:44 ` Oliver Neukum
2017-05-17 10:56 ` Baxter, Jim
2017-05-17 18:18 ` David Miller
2017-05-18 10:01 ` Oliver Neukum
2017-05-22 15:45 ` Baxter, Jim
2017-05-22 15:54 ` David Miller
2017-05-23 8:42 ` Oliver Neukum
2017-05-23 15:26 ` David Miller
2017-05-23 19:06 ` Baxter, Jim
[not found] ` <1497263047.15677.13.camel@suse.com>
2017-06-12 12:32 ` Baxter, Jim
2017-05-19 11:10 ` David Laight
2017-05-19 13:55 ` Bjørn Mork
2017-05-19 14:46 ` David Laight
2017-05-22 13:27 ` Oliver Neukum [this message]
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